• Journal of the Korean Solar Energy Society
• /
• v.37 no.5
• /
• pp.65-75
• /
• 2017

In this study, the change of heat loss due to the degree of deterioration of the XPS insulation in KEPCO's office buildings is analyzed. The acceleration aging test of the XPS insulation was carried out according to the test method A of KS M ISO 11561: 2009. The performance of the insulation was analyzed by applying it to the three - dimensional steady state heat transfer analysis program. The acceleration aging test of the XPS insulation, show that the thermal resistance performance decreased by 1.44% at the A regional headquarters, 0.85% at the B regional headquarters, 6.41% at the C branch office, 7.76% at the D regional headquarters, 8.51% at the E branch office, and by 8.54% at the F branch office respectively. Using simulation, we determined that the thermal resistance value of E branch office decreased by 8.04%, while its heat loss increased by 8.52%. At A regional headquarters, the thermal resistance decreased by 1.38%, and the heat loss increased by 1.51%. At D regional headquarters, these value are 6.82% and 7.17%, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.7
• /
• pp.645-649
• /
• 2007

Partial discharge(PD) test for simulated insulation defects of used hydro generator stator winding was conducted to analyze the PD Parameters. Simulated insulation defects are classified by 5 types corona, slot, internal, multi and aging defect. Phase resolved partial discharge, statistical parameter (skewness, kurtosis), PD magnitude as a function of the test voltage(Q-V curve) and PD magnitude change under test voltage for 2 minutes are used as PD parameters. The analysis of PD parameters by 4 types are proved to be useful methods. In particular, PD parameter characteristics of aging defect could help to assess the aging condition of stator winding because aging defect has more weak insulation strength than other insulation defects : PD distribution is wide and flat, PD rises rapidly near $0^{\circ}\;and\;180^{\circ}$ and Q-V curve rises sharply and then gently drops.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.05a
• /
• pp.471-474
• /
• 2005

This study investigates the nano/microstructure, the aging response, and the mechanical/tribological properties of the eutectic regions in rheoformed A356 alloy-T5 parts using nano/micro-indentation and mechanical scratching, combined with optical microscopy and atomic force microscope (AFM). Most eutectic Si crystals in the A356 alloy showed a modified morphology as fine-fibers. The loading curve for the eutectic region was more irregular than that of the primary Al region due to the presence of various particles of varying strength. The aging responses of the eutectic regions in the rheoformed A356 alloys aged at $150^{\circ}C$ for different times (0, 2, 4, 8, 10, 16, 24, 36, and 72 h) were investigated. Both Victors hardness $(H_v)$ and indentation $(H_{IT})$ test results showed a similar trend of aging curves, and the peak was obtained at the same aging time of 10 h. A remarkable size-dependence of the tests was found.

• Journal of Home Health Care Nursing
• /
• v.26 no.3
• /
• pp.278-287
• /
• 2019

Purpose: This study aims to examine the relationship between ego resilience, family resilience, and the perception of successful aging in nursing students; additionally, specific factors relating to the perception of successful aging were identified. Methods: The participants comprised 154 nursing students. Data were collected through the administration of self-reported questionnaires. Data analysis was then performed utilizing a t-test, an ANOVA, Pearson's correlation coefficients, and a multiple regression analysis. Results: Family resilience differed significantly based on the type of residence (p=.020) (i.e., living with grandparents (p=.048)). Perception of successful aging differed significantly based on grade (p<.001). The perception of successful aging showed a positive correlation relative to mode of communication and organizational pattern. The mode of communication accounted for 4.7% of perception of successful aging. Conclusion: The significance of the study on the importance of mode of communication was confirmed by identifying the effects of the perception of successful aging. Nursing students may actively cope with crises through communication; thus, successfully recognizing aging in order to lead a healthy life. Furthermore, having a high perception of successful aging while treating an increasing number of elderly patients at the clinical practice is believed to have a positive effect on patient care.

• Journal of the Korean Geosynthetics Society
• /
• v.20 no.2
• /
• pp.1-11
• /
• 2021

In this study, a study related to laboratory and pilot test were performed to use an environmental soil stabilizer developed to induce a hardening reaction similar to that of Ordinary Portland Cement (OPC) by using industrial by-products of blast furnace slag and the combustion ash of a circulating fluidized bed boiler as the main material. For this, specimens were prepared using liquid A of sodium silicate and silica sol, and liquid B of an environmental soil stabilizer (or OPC), and laboratory tests were performed to analyze the strength and environmental characteristics. And pilot test was performed on the aging reservoir, field permeability test and electrical resistivity survey were performed in the field to analyze the applicability. As a result of the laboratory test, the homo-gel compressive strength of the chemical injection material using the environmental soil stabilizer as liquid B was about 2.88 to 3.23 times greater than that of OPC. In addition, the elution amount of most heavy metals was lower than that of OPC, and the survival rate in the fish, acute toxicity test was 100%. Therefore, when judged based on the results of the laboratory test, it was analyzed to be superior to OPC in terms of strength and environment. In the results of the pilot test in the aging reservoir, when the environmental soil stabilizer was reinforced with liquid B of the chemical injection material, the coefficient of permeability in the aging reservoir decreased to 1/50 level. In addition, as a result of the electrical resistivity survey, it was analyzed that the electrical resistivity inside the aging reservoir increased as time passed, the saturation zone disappeared, and the overall reinforcement.

• Journal of Digital Convergence
• /
• v.20 no.5
• /
• pp.847-855
• /
• 2022

The purpose of this study is descriptive research to understand the effects of somatic symptoms, aging anxiety, and social support of middle-aged women on depression. Data collection was conducted from March 2020 to May 2020 using a structured questionnaire from a sample of 110 middle-aged women. The collected data were analyzed using descriptive statistics, t-test, ANOVA, Kruskal-Wallis test, Pearson's correlation coefficients and multiple linear regression analysis using SPSS Window 25.0 program. As a result of the study, the influence factors on the depression were confirmed by the somatic symptoms(β=0.42, p<.001), aging anxiety(β=0.35, p<.001) and total explanatory power of the variables was found to be 48.0%. Therefore, based on the result of this study, it suggests that more research is needed a program that considers somatic symptoms and aging anxiety when developing interventions to reduce depression and to verify the effectiveness.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.4
• /
• pp.911-919
• /
• 2013

This paper reports the development of test bed with the energy recovering technique using two-step boost converter. The device is utilized for LDC aging test of Hyundai Motor's LPI AVANTE HEV in mass production. The developed power recycle type test bed is designed as 1.5 kW class to test up to the maximum load power of LDC and is also designed to supply scant power supply up to 500 W after power recycle. The theoretical design analysis and operational characteristics analysis results of test bed are reported, and its practicality and reliability are verified through the test result. Also, the finally developed test bed confirms approximately 79~85 % energy saving effect compared to the usual traditional aging test system.

• Polymer(Korea)
• /
• v.27 no.3
• /
• pp.249-254
• /
• 2003

The variation of chemical structure and physical properties of crosslinked polyethylene (XLPE) during thermal aging process was investigated. The formation of carbonyl functional group resulting from thermal oxidation reaction of XLPE was monitored using X-ray photoelectron spectroscopy and near infrared (NIR) spectroscopy. It was observed that the intensity of carbonyl peak observed at 1715 nm linearly increased with aging time in NIR spectroscopy. The linear relationship between NIR peak absorbance and aging time confirmed that NIR spectroscopy might be used as a proper tool for monitoring the aging process of polymeric materials. Also the formation of crosslinks during the aging process was monitored using thermal mechanical analysis, stress-strain test, and Shore hardness test. The change in the physical properties, such as the increase in the glass transition temperature from 110 to 132$^{\circ}C$, the decrease in the strain from 265 to 110%, as well as the increase in the shore D hardness from 32 to 50, was observed during the aging process.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.9
• /
• pp.91-99
• /
• 2018

This research was conducted to examine successful aging and influencing factors in middle aged women. Data were collected from 189 middle-aged women in two cities. Data were collected from July to August 2017 using structured questionnaires. Data collected were analyzed by descriptive statistics, t-test, ANOVA, Pearson correlations, and multiple regression analysis. The results indicate that the perception of successful aging mean was 128.49 points (range: 33-165). Depression (r=-.20, p=.005) had a significant negative association with perception of successful aging. Family resilience (r=.49, p<.001) and life satisfaction (r=.54, p<.001) were positively correlated with perception of successful aging. The significant predictors of successful aging were age (${\ss}=-.15$, p=.013), family resilience (${\ss}=.24$, p=.002), and life satisfaction (${\ss}=.37$, p<.001), explaining 33.9% of the variance. Based on the study results, we suggest that it is necessary to develop and apply educational strategy to improve perception of successful aging.

• The Journal of the Korea Contents Association
• /
• v.19 no.1
• /
• pp.329-338
• /
• 2019

The purpose of this study was to examine the degree of aging anxiety and subjective well-being, and identify the effect of aging anxiety on subjective well-being among persons with mental disorder. A cross-sectional descriptive study design was used. 107 participants who were diagnosed with schizophrenia or mood disorder were recruited in D and C province. Collected data were analyzed using descriptive statistics, t-test, one-way ANOVA, Pearson correlation and multiple regression with SPSS 23.0 program. Mean score of aging anxiety and subjective well-being were $3.95{\pm}0.80$ and $3.53{\pm}0.73$ respectively. Aging anxiety had significant negative correlation with subjective well-being (r= -.48, p <.001). Aging anxiety, subjective health status, and employment status were significant influencing factors on subjective well-being, and these variables total explained for 31.1%. Therefore, it is necessary to provide a systematic and integrative strategy to cope with the aging anxiety for improving subjective well-being of person with mental disorder.