• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.4
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• pp.54-61
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• 2014

Effects of artificial thermal aging on color variations of various commercial papers (fine paper, coated paper, newsprint and filter paper) were investigated. With thermal aging at $105^{\circ}C$, most of papers showed a special trend in $a^*-b^*$ plane: the $a^*$ (red-green) values of the samples were initially reduced (heading to - $a^*$ side) and after a turning point they increased to +$a^*$ side while the $b^*$(blue-yellow) values were kept increased to +$b^*$ side (yellowing of paper). Different papers had different turning points for $a^*$ value. The filter paper consisted of a pure chemical pulp and the copy paper with OBA (optical brightening agent) showed the latest turing points. In addition, the papers without OBA showed less reduction in brightness compared with that with OBA, suggesting that OBA could adversely influence the brightness stability during thermal aging.

• Journal of the Korea Concrete Institute
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• v.12 no.6
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• pp.23-34
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• 2000

This paper reports the effects of curing temperature and aging on the strength and the modulus of elasticity. In oder to determine the strength and the modulus of elasticity with curing temperature and aging, experimental and analytical methods are adopted. The tests of 480 cylinders are carried out for type I, V and V with 15 percent replacement of fly ash cement concretes, which are cured at isothermal conditions of 10, 23, 35 and 5$0^{\circ}C$. and the concrete cylinders are tested at the ages of 1, 3, 7 and 28 days. According to the experimental results, the concrete subjected to high temperature at early ages attaines higher early-age compressive and splitting tensile strength but eventually attaines lower later-age compressive and splitting tensile strength. Even if modulus of elasticity has the same tendency, the variation of modulus of elasticity with curing temperature is smaller than that of compressive strength. Based on these experimental results, the relationships among compressive strength, modulus of elasticity and splitting tensile strength are proposed considering the effects of curing temperature, aging and cement type.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.66-72
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• 2015

This study was conducted to investigate the effects of optical brightening agents (OBA) on the chemical degradation characteristics of paper cellulose during humid heating aging. Three different types of OBAs were applied to a filter paper by dipping it in OBA solutions whose concentrations were controlled to 1% and 2%. The filter papers with an OBA were artificially aged at $80^{\circ}C$ and 65% RH, and the changes in pH of paper and viscosity of cellulose were evaluated. Their functional groups were also analyzed by ATR-FTIR (at-tenuated total reflectance fourier transform infrared spectroscopy). It was found that OBAs influenced the chemical degradation of paper cellulose during humid heating aging. Higher concentration of OBA solutions accelerated the degradation of paper cellulose. Especially, after aging for 12 days, the paper cellulose treated with the tetra-type OBA were the most significantly aged among the three types of OBAs. It was assumed that pH of OBA solutions affected the aging characteristics.

• Earthquakes and Structures
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• v.3 no.5
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• pp.649-673
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• 2012

Recent studies have highlighted the importance of accounting for aging and deterioration of bridges when estimating their seismic vulnerability. Effects of structural degradation of multiple bridge components, variations in bridge geometry, and comparison of different environmental exposure conditions have traditionally been ignored in the development of seismic fragility curves for aging concrete highway bridges. This study focuses on the degradation of multiple bridge components of a geometrically varying bridge class, as opposed to a single bridge sample, to arrive at time-dependent seismic bridge fragility curves. The effects of different exposure conditions are also explored to assess the impact of severity of the environment on bridge seismic vulnerability. The proposed methodology is demonstrated on a representative class of aging multi-span reinforced concrete girder bridges typical of the Central and Southeastern United States. The results reveal the importance of considering multiple deterioration mechanisms, including the significance of degrading elastomeric bearings along with the corroding reinforced concrete columns, in fragility modeling of aging bridge classes. Additionally, assessment of the relative severity of exposure to marine atmospheric, marine sea-splash and deicing salts, and shows 5%, 9% and 44% reduction, respectively, in the median value bridge fragility for the complete damage state relative to the as-built pristine structure.

• Journal of the Korean Society for Railway
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• v.8 no.2
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• pp.188-194
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• 2005

Aging characteristics of glass fabric/phenolic composites for tilting train subjected to combined environmental aging factors were investigated. A 2.5KW accelerated aging tester with a xenon-arc lamp was used to provide environmental aging factors such as temperature, moisture, and ultraviolet. A series of aging tests were conducted up to 3000 hours and several types of specimens were prepared along the warp direction and the fill direction. Mechanical degradations for tensile, flexural, and shear properties were evaluated as a function of exposure times through a material testing system. Thermal analysis properties such as storage shear modulus, loss shear modulus, and tan 3 were measured through a dynamic mechanical analyzer. Finally exposed surfaces of the composites were examined using a scanning electron microscope. According to the experimental results, mechanical properties and thermal analysis properties of glass fabric/phenolic composites were found to be slightly degraded as a function of exposure times due to combined environmental effects.

• Food Science of Animal Resources
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• v.39 no.3
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• pp.379-387
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• 2019

The effects of dry-aging on changes in taste compounds and electronic taste sensing traits of pork were investigated. Ten pork belly and shoulder blade cuts were divided into wet-aging and dry-aging treatments and stored for 21 days at $2^{\circ}C$. The contents of nucleotides and free amino acids, and electronic tongue analysis were investigated at different aging periods (1, 7, 14, and 21 days). The contents of inosine and hypoxanthine of dry-aged pork cuts increased more rapidly, and they were significantly (p<0.05) higher than wet-aged pork cuts. Total free amino acids of dry-aged pork cuts were also significantly (p<0.05) higher than those of wet-aged pork cuts after 21 days of aging. Consequently, umami intensity of dry-aged pork cuts increased more rapidly and the values were significantly (p<0.05) higher than those of wet-aged pork during 21 days of aging. Results suggested that the better palatability of dry-aged pork cuts might be due to higher umami intensity in relation to higher contents of inosine, hypoxanthine, and free amino acids.

• Journal of East-West Nursing Research
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• v.29 no.1
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• pp.6-14
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• 2023

Purpose: The purpose of this study was to determine effects of posttraumatic growth, aging anxiety, and spirituality on successful aging in late middle-aged women. Methods: Participants were 128 late middle-aged women. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients and hierarchical multiple regression with SPSS WIN 23.0 program. Results: Results showed that significant factors influencing successful aging were spirituality and monthly income. This regression model explained 21.4% of the variance in successful aging. Conclusion: These results provided the basic data for establishing an intervention strategy to increase the level of successful aging of middle-aged women. In addition, the results suggested that development of a nursing intervention program is in need.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.203-206
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• 2008

Transformation of austenite to martensite during cold rolling has been widely used to strengthen metastable austenitic stainless steel grades. Aging treatment of cold worked metastable austenitic stainless steels, including ${\alpha}'$-martensite phase, results in the further increase of strength, when aging is performed in $200^{\circ}C$ to $450^{\circ}C$ temperature range. The purpose of the present study was to evaluate the effect of time and temperature on the stress-strain behavior of cold worked austenitic stainless steels. The amount of ${\alpha}'$-martensite during cold working and aging was examined by ferrite scope and X-ray diffraction (XRD). During aging at $450^{\circ}C$ for 1hr, tensile strength dramatically increased by 150MPa. Deformed metastable austenitic steels containing the "body-centered" ${\alpha}'$-martensite are strengthened by the diffusion of interstitial solute atoms during aging at low temperature.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.320-326
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• 2003

Recently several studies have indicated that ubiquinone-l0 (CoQ-10) decrease with aging in various organs of the human body. The decrease of ubiquinone-10 in the aging process suggests the reduction of both energy production in mitochondria and anti-oxidation with aging. Based on these findings, Ubiquinone-10 is being focused at as an anti-aging agent in the cosmetic market.(omitted)

• Journal of the Korean Ceramic Society
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• v.46 no.2
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• pp.219-223
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• 2009

Effects of MgO or $R_2O_3$(R:Dy, Ho, Yb) on the capacitance aging behavior of multilayer ceramic capacitors (MLCCs) based on $BaTiO_3$ dielectrics under DC electrical fields has been studied. At a DC field of 1 $V{/\mu}m$, the capacitance of MLCC specimens dropped immediately in a very short period (<10 s, the first stage) and then decreased continuously with time (the second stage). Mn doping significantly increased the aging rate in the second stage. The addition of MgO or $R_2O_3$ notably decreased the second stage aging rate of Mn-doped specimens. Yb doping gives rise to the lowest aging rate in the second stage, which is due to the larger population of defect dipoles associated with oxygen vacancies.