• Title/Summary/Keyword: Useful life

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Various Perspectives to Read the Micro-History of Korean Housing after the Period of Opening the Port (근대 이후 한국주거의 미시사를 보는 다양한 관점)

  • Hong Hyung-Ock
    • Journal of Families and Better Life
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    • 제23권5호
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    • pp.79-92
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    • 2005
  • The purpose of this study was to explore the various perspectives to read micro-history of Korean housing after the period of Opening the Port for foreigners. This study were designed to adapt original theory for exploring the unique housing perspectives without using strict basic assumption which were already developed in the area of sociology, history, anthropology and philosophy. Research method applied was literature review. Each perspective might give useful insight to read the micro-history of Korean housing on the way of change after the Period of Opening the Port in Korea. Adapted perspectives to housing history were critical theory perspective, microsociological perspective, everyday life perspective(phenomenology tradition, symbolic interaction tradition, Marxist tradition), discourse perspective, exchange theory perspective, conflict theory perspective, and life course perspective. Conclusively, each perspective must be adapted multi-supportively to read the housing phenomena, because housing change derived from complex causes and factors. The fruit of this study was to ensure the adaptable viewpoint to housing were useful to read the micro-history of housing change.

A study on Accelerated Life Prediction of Gas Welded joint of STS301L (1. Plug and Ring type) (STS301L 가스용접이음재의 가속수명에측에 관한 연구 (1. Plug and Ring type))

  • Baek, Seung-Yeb;Bae, Dong-Ho
    • Proceedings of the KSME Conference
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    • 대한기계학회 2008년도 추계학술대회A
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    • pp.1355-1360
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    • 2008
  • Stainless steel sheets are widely used as the structure material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. Gas welding is very important and useful technology in fabrication of an railroad car and vehicles structure. However fatigue strength of the gas welded joints is considerably lower than parent metal due to stress concentration at the weldment, fatigue strength evaluation of gas welded joints are very important to evaluate the reliability and durability of railroad cars and to establish a criterion of long life fatigue design. In this paper, ${\Delta}P-N_f$ curve were obtained by fatigue tests. Using these results, the accelerated life test (ALT) is conducted. From the experimental results, an acceleration model is derived and acceleration factors are estimated. So it is intended to obtain the useful information for the fatigue lifetime of plug and ring gas welded joints and data analysis by statistic reliability method, to save time and cost, and to develop optimum accelerated life prediction plans.

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Reliability Assessment and Accelerated Life Prediction of Gas Welded Joint in the Rail Road Car Body (1. Plug and Ring Type) (철도차량 차체 가스용접 이음재의 가속수명예측과 신뢰도 평가)

  • Baek, Seung-Yeb
    • Journal of Welding and Joining
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    • 제28권1호
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    • pp.77-85
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    • 2010
  • Stainless steel sheets are widely used as the structure material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. Gas welding is very important and useful technology in fabrication of a railroad car and vehicles structure.However fatigue strength of the gas welded joints is considerably lower than parent metal due to stress concentration at the weld, fatigue strength evaluation of gas welded joints are very important to evaluate the reliability and durability of railroad cars and to establish a criterion of long life fatigue design. In this paper, $({\Delta}{\sigma}_a)_R-N_f$ curve were obtained by fatigue tests. Using these results, the accelerated life test(ALT) was conducted. From the experimental results, an acceleration model was derived and acceleration factors are estimated. So it is intended to obtain the useful information for the fatigue lifetime of plug and ring gas welded joints and data analysis by statistic reliability method, to save time and cost, and to develop optimum accelerated life prediction plans.

A Study on Accelerated Life Prediction Automation of Gas Welded Joint of STS301L (Plug and Ring Type) (STS301L 가스용접이음재의 가속수명예측 자동화에 관한 연구 (Plug and Ring Type))

  • Baek, Seung-Yeb;Sohn, Il-Seon
    • Transactions of the Korean Society of Automotive Engineers
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    • 제19권3호
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    • pp.1-8
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    • 2011
  • Stainless steel sheets are widely used as the structure material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. Gas welding is very important and useful technology in fabrication of an railroad car and vehicles structure. However fatigue strength of the gas welded joints is considerably lower than parent metal due to stress concentration at the weldment, fatigue strength evaluation of gas welded joints are very important to evaluate the reliability and durability of railroad cars and to establish a criterion of long life fatigue design. In this paper, ${\Delta}-N_f$ curve were obtained by fatigue tests. Using these results, the accelerated life test (ALT) is conducted. From the experimental results, an acceleration model is derived and acceleration factors are estimated. So it is intended to obtain the useful information for the fatigue lifetime of plug and ring gas welded joints and data analysis by statistical reliability method, to save time and cost, and to develop optimum accelerated life prediction plans.

Lifetime Prediction of Rubber Pad for High Speed Railway Vehicle (고속철도용 레일패드 노후화 정량화 방안 연구)

  • Woo, Chang-Su;Choe, Byeong-Ik;Park, Hyun-Sung;Yang, Shin-Chu;Jang, Sung-Yep;Kim, Eun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • 제33권8호
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    • pp.739-744
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    • 2009
  • Rail-pad is an important and readily replaceable component of a railway track, as it is the elastic layer between the rail and the sleeper. Characteristics and useful lifetime prediction of rail-pad was very important in design procedure to assure the safety and reliability. In this paper, the degradation of rail pad properties as a function of their in-service life is studied with a view of developing a technique for predicting the optimum period of track maintenance with regard to pad replacement. In order to investigate the useful lifetime, the accelerate test were carried out. Accelerated test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the acceleration test, several useful lifetime prediction for rail-pads were proposed.

Highly Specific Detection of Five Exotic Quarantine Plant Viruses using RT-PCR

  • Choi, Hoseong;Cho, Won Kyong;Yu, Jisuk;Lee, Jong-Seung;Kim, Kook-Hyung
    • The Plant Pathology Journal
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    • 제29권1호
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    • pp.99-104
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    • 2013
  • To detect five plant viruses (Beet black scorch virus, Beet necrotic yellow vein virus, Eggplant mottled dwarf virus, Pelargonium zonate spot virus, and Rice yellow mottle virus) for quarantine purposes, we designed 15 RT-PCR primer sets. Primer design was based on the nucleotide sequence of the coat protein gene, which is highly conserved within species. All but one primer set successfully amplified the targets, and gradient PCRs indicated that the optimal temperature for the 14 useful primer sets was $51.9^{\circ}C$. Some primer sets worked well regardless of annealing temperature while others required a very specific annealing temperature. A primer specificity test using plant total RNAs and cDNAs of other plant virus-infected samples demonstrated that the designed primer sets were highly specific and generated reproducible results. The newly developed RT-PCR primer sets would be useful for quarantine inspections aimed at preventing the entry of exotic plant viruses into Korea.

A Study of the Relationships Between Daily Life Stress, Self-efficacy and University Student Life Adjustment

  • Lee Young Whee;Lee Young Ja
    • Journal of Korean Academy of Nursing
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    • 제35권4호
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    • pp.664-671
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    • 2005
  • Purpose. This correlation study was undertaken to examine the relationships between daily life stress, self-efficacy and university student life adjustment and to analyze the self-efficacy affecting that university student life adjustment. Methods. 265 university students were recruited from several participating required undergraduate classes. They were surveyed as the subject of this study. Data collection was conducted through the use of questionnaires. Results. The university life adjustment level showed a maximum score of 9 with the mean score 5.22. A negative correlation was found between daily life stress and university life adjustment. Also, there was positively correlation between self-efficacy and university life adjustment. Self-efficacy and daily life stress accounted for $23\%$ of the variance in university student life adjustment. Conclusion. According to the results, self-efficacy is a useful concept in helping overall university life adjustment. Therefore, university student consultation office or nurse should consider the program based on self-efficacy in order to help university students to better adapt to university life.

A Qualitative Study on the Remarried Elderly's Stress and Adaptation to Stepfamily Life (노년기의 재혼가족생활 스트레스에 대한 경험적 연구 - 재혼노인 및 그 배우자를 중심으로 -)

  • 박경난
    • Journal of Families and Better Life
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    • 제15권4호
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    • pp.183-200
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    • 1997
  • The purpose of this study was to identify the stress of remarried elderly in their remarried life. There were 10 remarried elderly respondents. The data was collected by in-depth personal interview. Focusing on the situation of remarried family life the remarried elderly perceived various stress. Those were the stress from the status of remarried person and the stress from relations with their own children/ new spouse/ new spouse's children/ ex-spouse and ex-kin/ sibling and relatives and friends. The results of this study could be a useful material for elderly's remarriage preparation program.

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Useful lifetime prediction of rail-pad by using the accelerated heat aging test (가속 열노화시험을 통한 레일패드 사용수명예측)

  • Woo, Chang-Su;Park, Hyun-Sung;Choi, Byung-Ik;Yang, Sin-Chu;Jang, Sung-Yep;Kim, Eun
    • Proceedings of the KSR Conference
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    • 한국철도학회 2009년도 춘계학술대회 논문집
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    • pp.1010-1015
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    • 2009
  • Rail-pad is an important and readily replaceable component of a railway track, as it is the elastic layer between the rail and the sleeper. Characteristics and useful lifetime prediction of rail-pad was very important in design procedure to assure the safety and reliability. In order to investigate the useful lifetime, the accelerate test were carried out. Accelerated test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the acceleration test, several useful lifetime prediction for rail-pads were proposed.

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Strain elastography of palatal tumors in conjunction with intraoral ultrasonography, computed tomography, and magnetic resonance imaging: 2 case reports

  • Ogura, Ichiro;Toshima, Hiroo;Akashiba, Tohru;Ono, Junya;Okada, Yasuo
    • Imaging Science in Dentistry
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    • 제50권1호
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    • pp.73-79
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    • 2020
  • Computed tomography (CT) and magnetic resonance imaging (MRI) can be useful for the evaluation of palatal lesions, and strain elastography (performed together with intraoral ultrasonography) is a relatively new sonographic imaging modality. This report describes 2 clinical cases in which strain elastography was used to assess palatal tumors in conjunction with intraoral ultrasonography, CT, and MRI. In the first case, diagnosed as a myoepithelioma, the strain was determined to be 0.000% (strain of normal tissue, 0.556%). In the second case, diagnosed as an adenoid cystic carcinoma, the determined strain was 0.000% (strain of normal tissue, 1.077%). Therefore, we conclude that intraoral strain elastography can be useful for evaluating palatal lesions.