• Title/Summary/Keyword: Life testing

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A Study on the Curing of Positive Plate and Grid to Improve the Capacity of the Lead-Acid Batteries (납축전지의 성능 향상을 위한 양극판의 숙성과 그리드에 관한 연구)

  • Ku, Bon-Keun;Jeong, Soon-Wook
    • Journal of the Korean Applied Science and Technology
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    • v.25 no.1
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    • pp.41-47
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    • 2008
  • This study was conducted to made a grid alloy (Pb-Ca-Sn-Al) which has a temporary composition ratio in order to improve the efficiency of lead acid batteries. The positive activity material made a 3BS(tri-basic lead sulfate; $3PbO{\cdot}PbSO_4{\cdot}H_2O$) by a low temperature curing and it evaluates the plate efficiency through the life cycle testing. The initial current capacity of low temperature curing plate was excellent but the life cycle was not good (S1). As for the S2 plate, however, the initial current capacity and the life cycle were superior.

Life Prediction of High Pressure Hydraulic Hose Assemblies by the Impulse Test

  • KIM, Hyoung-Eui;LEE, Yong-Bum;Kwon, Young-Il
    • Corrosion Science and Technology
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    • v.3 no.5
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    • pp.209-215
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    • 2004
  • Flexible hydraulic hose assembly that consists of hose and joints is used widely on various construction heavy equipments, agricultural machines, motor vehicles, and industrial heavy machines that require flexibility on hydraulic pipelines. It is classified by the maximum usage pressure which is determined by the winding layers of coiling steel wire and the inner diameter of the hoses. In this paper, we designed and performed an accelerated life test for assessing the reliability of a flexible hydraulic hose assembly. In the proposed accelerated life test, typical impulse pressure testing method is applied with the half omega flexing operation to simulate the practical flexing motion of the hose assembly.

Development of the Meaning in Life Scale for Older Adults (노인의 삶의 의미 측정 도구 개발)

  • Lee, Si Eun;Hong, Gwi-Ryung Son
    • Journal of Korean Academy of Nursing
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    • v.47 no.1
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    • pp.86-97
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    • 2017
  • Purpose: The purpose of this study was to develop and test the psychometric properties of the newly developed instrument, Meaning in Life, for elderly Korean people. Methods: Ten older adults participated in the qualitative research used to develop the initial items. Participants for the psychometric testing were 371 community-dwelling older adults. Validity and reliability analyses included content, construct, and criterion-related validities, internal consistency, and test-retest reliability. Results: The Meaning in Life Scale consisted of 12 items with three distinct factors; value of life, source of life, and will to live, which explained 86.7% of the total variance. A three-factor structure was validated by confirmatory factor analysis. Criterion-related validity was supported by comparison with the Purpose in Life Test (r=.74). Reliabilities were secured with test-retest reliability of Intra-class Correlation Coefficient (ICC) .85 and the Cronbach's alpha coefficient .90. Conclusion: The results of this study indicate that this instrument is useful to measure meaning in life in Korean elders.

An Accelerated Life Test for Burnout of Tungsten Filament of Incandescent Lamp (텅스텐 백열전구의 필라멘트 단선에 대한 가속수명시험)

  • Kim Jin-Woo;Shin Jae-Chul;Kim Myung-Soo;Lee Jae-Kook
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.7 s.238
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    • pp.921-929
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    • 2005
  • This paper presents an accelerated life test for burnout of tungsten filament of incandescent lamp. From failure analyses of field samples, it is shown that their root causes are local heating or hot spots in the filament caused by tungsten evaporation and wire sag. Finite element analysis is performed to evaluate the effect of vibration and impact for burnout, but any points of stress concentration or structural weakness are not found in the sample. To estimate the burnout life of lamp, an accelerated life test is planned by using quality function deployment and fractional factorial design, where voltage, vibration, and temperature are selected as accelerating variables. We assumed that Weibull lifetime distribution and a generalized linear model of life-stress relationship hold through goodness of fit test and test for common shape parameter of the distribution. Using accelerated life testing software, we estimated the common shape parameter of Weibull distribution, life-stress relationship, and accelerating factor.

The Effect of Self-Esteem between Leisure Activity and Life Satisfaction of the Elderly (노인의 여가활동과 생활만족도가 자아존중감에 미치는 영향)

  • Kim, Young-Gil
    • Journal of East-West Nursing Research
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    • v.14 no.1
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    • pp.44-55
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    • 2008
  • Purpose: This research concludes the 110 male and female elderlies who are over 60 years old in C welfare center of G city to examine the effect of self-esteem between leisure activity and life satisfaction. Method: The types of participation leisure consist of 20 questions in five different categories. To measure the value of life satisfaction, the scale of life satisfaction for the elderly which is developed by Choi (1986) is used. The self-esteem was measured by the scale developed by Rosenberg (1965) and translated by Jeon (1974). The data were analyzed by SPSS including frequency, ANOVA, Duncan, Pearson correlation coefficient and multiple regression. Result: There was significant relationship among leisure activity and life satisfaction (r= .410, p= .000), leisure activity and self-esteem (r= .432, p= .000) and life satisfaction and self-esteem (r= .765, p= .000). After testing how leisure activity has effect on the self-esteem, it appears to be 17.9% and after adding life satisfaction it increases to be 59.5%. Conclusion: Synthesizing all following results, there were needed to bepersonal and global effort in many ways to satisfy the economical need of the elderly, and more supports onincreasing participation of the elderly in leisure.

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The Effects of Perceived Ageism and Appearance Satisfaction on Appearance Related Quality of Life among Korean Older Women (노년여성의 연령차별 인식과 외모만족도가 외모관련 삶의 질에 미치는 영향)

  • Yu, Haekyung;Lee, Minsun
    • Journal of the Korean Society of Clothing and Textiles
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    • v.43 no.1
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    • pp.112-124
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    • 2019
  • This study investigated the effects of perceived ageism on appearance related quality of life through appearance satisfaction among older Korean women. Testing the proposed model showed associations among variables and the mediating effects of appearance satisfaction in the relationship between perceived ageism and appearance related psychological and social quality of life. Structural equation modeling analyses upheld the proposed model for 221 women aged 60 and over. The results revealed that older women's perception of ageism negatively influenced appearance satisfaction that subsequently affected perceived levels of both psychological and social quality of life in a negative direction. The direct effects of perceived ageism on both psychological and social quality of life were not found; however, the indirect effects of perceived ageism on these two variables through appearance satisfaction were found significant and negative. This indicated a fully mediating effect of appearance satisfaction in the relationships. The results of this study highlight that perceptions of ageism and its association with body image should be considered to understand the overall quality of life among older women.

The influence of adolescents' life satisfaction, and perceived parental rearing style on adolescents' depression: Verification of mediating effect of resilience (청소년의 삶의 만족도 및 인지된 부모양육방식이 청소년의 우울에 미치는 영향: 자아탄력성의 매개효과 검증)

  • Sim, Jeong Yeon;Yoon, Gyung-Ja
    • Journal of Family Relations
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    • v.22 no.2
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    • pp.27-50
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    • 2017
  • Objectives: This study explored the effect of adolescents' sociodemographic variables, parenting rearing styles, resilience, and life satisfaction on adolescents' depression. The resilience as mediating effects of parental rearing styles and life satisfaction on depression was examined as well. Method: The data were from 2,108 middle school freshmen panel of a national sample at the forth year, Korea Children and Youth Panel Survey(KCYPS). Hierarchical multiple regressions and mediation regression analyses, steps for testing mediation by Baron and Kenny, were conducted. Results: Adolescents' resilience had both direct and mediating significant effects, showing that resilience partially mediated the effects of affective parental rearing style and life satisfaction on depression, respectively. Life satisfaction had the most significant impact on adolescents' depression. Conclusions: While some parental rearing styles were significant, adolescents' personal properties including resilience and life satisfaction revealed the most significant explanatory power of adolescents' depression. Life satisfaction was the most powerful predictor for lessening adolescents' depression.

Numerical Verification of B-WIM System Using Reaction Force Signals

  • Chang, Sung-Jin;Kim, Nam-Sik
    • Journal of the Korean Society for Nondestructive Testing
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    • v.32 no.6
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    • pp.637-647
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    • 2012
  • Bridges are ones of fundamental facilities for roads which become social overhead capital facilities and they are designed to get safety in their life cycles. However as time passes, bridge can be damaged by changes of external force and traffic environments. Therefore, a bridge should be repaired and maintained for extending its life cycle. The working load on a bridge is one of the most important factors for safety, it should be calculated accurately. The most important load among working loads is live load by a vehicle. Thus, the travel characteristics and weight of vehicle can be useful for bridge maintenance if they were estimated with high reliability. In this study, a B-WIM system in which the bridge is used for a scale have been developed for measuring the vehicle loads without the vehicle stop. The vehicle loads can be estimated by the developed B-WIM system with the reaction responses from the supporting points. The algorithm of developed B-WIM system have been verified by numerical analysis.

Evaluation Methods for Flat Crush Resistance of Corrugated Fiberboard with Microflutes

  • Youn, Hye-Jung;Kwon, Hyun-Seung;Lee, Hak-Lae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.41 no.5
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    • pp.8-14
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    • 2009
  • Corrugated fiberboard is a widely used packaging material because of its high compressive strength and stiffness despite light weight. Corrugated fiberboards with microflutes with height $\leq$ 1.5 mm, such as E, F or G, have been developed. As microflutes have a different geometry from other conventional flutes, they may behave differently in testing and require a new testing method. Therefore, we evaluated the flat crush resistance of corrugated fiberboard with microflutes according to the ISO and TAPPI standard test methods. In addition, the effects of specimen area and platen compression rate were examined. The goal of this study was to identify an appropriate method for flat crush test (FCT) of corrugated fiberboard with microflutes. When a test piece with a standard area was subjected to the FCT in accordance with ISO and TAPPI methods, microflute corrugated fiberboard demonstrated a different load-displacement curve. An area of 20 $cm^2$ was determined to be the most appropriate for FCTof microflute corrugated fiberboard.

Spectroscopic Techniques for Nondestructive Detection of Fungi and Mycotoxins in Agricultural Materials: A Review

  • Min, Hyunjung;Cho, Byoung-Kwan
    • Journal of Biosystems Engineering
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    • v.40 no.1
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    • pp.67-77
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    • 2015
  • Purpose: Fungal secondary metabolite (mycotoxin) contamination in foods can pose a serious threat to humans and animals. Spectroscopic techniques have proven to be potential alternative tools for early detection of mycotoxins. Thus, the aim of this review is to provide an overview of the current developments in nondestructive food safety testing techniques, particularly regarding fungal contamination testing in grains, focusing on the application of spectroscopic techniques to this problem. Methods: This review focuses on the use of spectroscopic techniques for the detection of fungi and mycotoxins in agricultural products as reported in the literature. It provides an overview of the characteristics of the main spectroscopic methods and reviews their applications in grain analysis. Results: It was found that spectroscopy has advantages over conventional methods used for fungal contamination detection, particularly when combined with chemometrics. These advantages include the rapidness and nondestructive nature of this approach. Conclusions: While spectroscopy offers many benefits for the detection of mycotoxins in agricultural products, a number of limitations exist, which must be overcome prior to widespread adoption of these techniques.