• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.576-580
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• 2008

Rubber material properties and useful life evaluation are very important in design procedure to assure the safety and reliability of the rubber components. In this paper, the evaluation of characteristics and useful life prediction of rubber component for elevator cabin were experimentally investigated. The material test and accelerated heat-aging test were carried. Rubber material constants were obtained by curve fittings of simple tension, pure shear and bi-axial tension test data. Heat aging 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 rubber material and component test several useful life prediction equations for rubber component were proposed. Predicted useful life of rubber component for elevator cabin agreed fairly with the experimental lives.

• 한국염색가공학회지
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• 제29권3호
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• pp.155-161
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• 2017

In CPB(Cold-Pad-Batch) dyeing, the rubber of the padder roll is influenced by the heat, chemical and mechanical influences and thus aging of the padder roll rubber occurs. This study presents an accelerated thermal aging test of the CPB padder roll rubber with strong alkali conditions. Using Arrhenius formula of the various property values for the various aging temperatures($80^{\circ}C$, $90^{\circ}C$, $100^{\circ}C$) of the padder roll, the accelerated life predictions could be calculated. The threshold value of the property was set at different values. The hardness was set at the point where 5% degradation occurs based on the actual use conditions, and the tensile strength was set at the point where 50% degradation occurs based on the general life prediction standards. From the results of the different physical properties at differing temperatures, the Arrhenius plot could be obtained. Through the usage of the Arrhenius Equation, significant duration expectation could be predicted, and the chemical aging behavior of the CPB padder roll could be found at the arbitrary and actual temperatures.

• 한국압력기기공학회 논문집
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• 제7권4호
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• pp.12-18
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• 2011

The renewed global interest in nuclear power has arisen from the need to reduce greenhouse gas emissions and to provide sufficient electricity for a growing global population. Many countries with nuclear power plants (NPPs) are still implementing license extensions of 10~20 years, and even consideration is being given to the concept of life-beyond-60, a further period of license extension from 60 to 80 years. To solve the materials aging problem is integral to its success. A foundation for effective aging management of nuclear power plants is that aging is properly taken into account at each stage of a plant's lifetime, i.e. in design, manufacture, construction and operation including long term operation and decommissioning. To evaluate the plant aging phenomena, a lot of background information such as materials and environment of the parts of the reactor and plant systems is needed by the experts. Information on degradation mechanisms is also used. In this paper, a regulation on the integrated materials aging management for nuclear facilities is proposed. The proposed regulation identifies key elements of effective aging management for nuclear power plants and provides the requirements on aging management for nuclear facilities throughout all stages of the lifetime of the plant.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 춘계학술발표회요약집
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• pp.462-462
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• 2001

• KDI Journal of Economic Policy
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• 제26권1호
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• pp.105-140
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• 2004

Korea is entering the class of aging population nations. This paper investigates the extent demographic factors and the aging population affect the saving rate, using an extended life-cycle/permanent-income hypothesis on saving. The results of the tests with Korean household survey data from 1977 to 2002 reveal that real saving rates increase when the duration of lifetime and per household real disposable income rise, and decrease when the growth rate of income and net worth-to-GDP ratio rises. The growth rate of per household real disposable income has negative effects, suggesting that households calculate their life cycle income in a forward looking manner. The elasticities with respect to a change in the lifetime horizon and the growth rate of per household income are 0.58 and -0.03, respectively. A one percent rise in the net worth to GDP ratio reduces the saving rate by 0.3 percent. A one percent rise in per household income increases it by 0.33 percent. The younger-age and the elder-age dependency ratios have insignificant effects on the household saving rate behavior. When Korean life expectancy rises, the private saving rate declines modestly and the government saving rate declines substantially. The economy's real net saving rate declines from 33 percent in 2002 to 30 percent by the year 2030.

• 사상체질의학회지
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• 제14권3호
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• pp.7-16
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• 2002

Purpose The goal of this study tried to provide aging and life span in Sasang Constitutional Medicine. Methods It was researched Master Dong-Mu's documentary records about aging and the life span represented by ${\ulcorner}$Dongyi Soose Bowon Sasang Chobongyun${\lrcorner}$ and ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$ published in 1901. Results & conclusion 1. A principal of regimen according to Sasang Constitutional Medicine isn't medicational method but non-medicational method. There are control mind and upright oneself. 2. Dong-Mu's the views of the span of life represented by 'Inherent vitality' that a term means health promoting and forecasting length of the life. He also emphasizied a natural power of recovery from damaged vitality. 3. Greed is reduced one's lifetime. It is originated by bias for 'joy-anger -sorrow-pleasure'. The other example is 'Liquor-Sex-Property- Authority'. 4. The way of prolonging lifetime what managed small visceral intestines through constitutional upright oneself. This is found on pathology, care of health and constitutional 'Knowledge and Deed'.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.1009-1010
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• 2008

This paper presents a real-time aging measurement and feasible compensation system for the prolonged lifetime of OLED panel. The proposed system is composed of four parts, a PC with a man-machine interface, a measurement block, an adaptive amplifier block, and a compensation block. We apply a tree algorithm for less complexity and convenience of measurement on the degree of aging. An adaptive multi-stage differential amplifier is also implemented to deal with a various range of input voltages at the same spot.

• Nuclear Engineering and Technology
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• 제43권3호
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• pp.279-286
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• 2011

The aging degradation and lifetime assessment of a domestic class 1E Ethylene-Propylene-Diene-Monomer (EPDM), which is a popular insulating elastomer for electrical cables in the nuclear power plants, were studied for equipment qualification verification under the Loss of Coolant Accident (LOCA) conditions. The specimens were acceleratively aged, underwent a LOCA environment, as well as tested mechanically, thermo-gravimetrically, and spectroscopically according to the American Society of the Testing of Materials (ASTM) procedures. The tensile test results revealed that the elongation at break gradually decreased with an increasing aging temperature. The lifetime of EPDM aged isothermally at $140^{\circ}C$ was 1,316 hours and reduced to 1,120 hours after experiencing the severe accident test. The activation energies of the elongation reduction were $1.10{\pm}0.196$ eV and $0.93{\pm}0.191$ eV before and after the LOCA condition, respectively. The TGA test results also showed that the activation energy of the aging decomposition decreased from 1.35 eV to 1.02 eV after undergoing the LOCA environment. Although the mechanical property changes were discernibly observed during the aging process, along with the LOCA simulation, the FT-IR analysis showed that the spectroscopic peaks and their intensities did not alter significantly. Therefore, it can be concluded that the degradation of the domestic class 1E EPDM due to aging can be tolerable, even in severe accident conditions such as LOCA, and thus it qualifies as a suitable insulating material for electrical cables in the nuclear power plants.

• 전기학회논문지
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• 제66권8호
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• pp.1278-1284
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• 2017

As of December 2016, there are 608,828 elevators in operation in Korea and 179,790 elevators in more than 15 years. 30.4% of all elevator are aging. Improved maintenance of the elevator and proactive replacement of the parts of the elevator can extend the lifetime of the elevator and ensure safety. An unclean environment reduces the lifetime of elevator parts. If you do not clean the environment and prevent preventive parts replacement, eventually shortening the lifetime of the parts connected to the failed part or causing more damage will result in greater economic loss. Also, the risk of elevator safety accidents due to failures of elevator parts will be increased accordingly. The study of optimum replacement time of elevator parts will contribute to prevention of safety accident of elevator and prolongation of lifetime of elevator through preventive replacement of elevator parts.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1631-1635
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• 2002

In order to be good display, the ac PDP lifetime should be guaranteed over 30000 hours. Therefore, to satisfy these demands, it is need to find out main factors in ac PDP affecting the lifetime. In this paper, the characteristics of lifetime as a parameter of the MgO deposition rate conditions is investigated. MgO protective layers is fabricated by E-beam. Before measuring the lifetime we have carefully peformed high temperature evacuation and aging procedure, which is essential for providing the initial condition of our experiment. If MgO deposition rate increased, MgO film becomes dense and an adhesive power of MgO film gets better and because occurrence rate of the MgO cluster decreases, lifetime of MgO will be improved. As a result, ac PDP lifetime can be improved due to the improvement of MgO by MgO preparation conditions.