• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.5
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• pp.42-46
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• 2008

The papers in preserved books and archives experience aging which was affected by a variety of factors. Thus, the studies concerning impacts of those factors on paper aging are required. In this research, a simulation of a short-time accelerated paper aging was conducted in order to examine the effects of acid and metals (alum, copper (II) sulfate, copper (II) chloride, and iron (III) chloride) on the natural paper aging for a long time. As a result of experiments, it is found that both acid and metals have impacts on paper aging. Alum resulted in the significant decrease of pH, brightness, folding endurance, and viscosity of paper. Both copper (II) chloride and iron (III) chloride also resulted in the decrease of brightness, folding endurance, and viscosity of paper. In more detail, paper aging by iron (III) chloride showed much more significant than that by copper (II) chloride. The paper aging in case of copper (II) sulfate coexisting sulfate ion, where metal absorbed moisture was higher than in case of paper treated only by alum. This result indicated that metal catalyzes paper aging by acid. Based on these results, it was revealed that both alum and metal are the major factors in paper aging. In particular, paper aging was far more accelerated in case when acid and metals existed in paper at the same time.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1832-1838
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• 2010

Aging of transformer insulating material in natural ester insulating oil is compared to that in conventional transformer oil. Aging of insulating paper and insulating oil have been studied by performing accelerated thermal aging test. Sealed aging test vessels containing cooper, laminated core, Kraft paper and insulating oil(natural oil or mineral oil) were aged at $140^{\circ}C$ for 500, 1000, 1500 and 2000 hours. Insulating oils after aging are investigated with total acid number, breakdown voltage and viscosity. Also, degradation of insulating paper after aging is determined using breakdown voltage and mechanical strength. Accelerated aging studies demonstrate a slower aging rate for natural ester insulating oil compared to the rate for conventional mineral oil.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.339-347
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• 2011

This study was carried out in order to manufacture the high quality coated paper. High quality coated paper includes not only present state but also the state of the future. So in this study, acrylic-styrene emulsion which polymerized in laboratory was compared with SB(Styrene-butadiene) latex during thermal aging. The coated paper with three different formulations which controlled the dosage of acrylic-styrene emulsion were prepared. The coated paper were thermally aged at $105^{\circ}C$ for 18days and the optical properties were measured. Brightness, whiteness and CIE L value were higher during thermal aging with increasing amount of acrylic-styrene emulsion. CIE $a^*$ value was higher and CIE $b^*$ value decreased with increasing amount of acrylic-styrene emulsion. These results indicate that high quality coated paper which has anti -thermal aging property can be manufactured with acrylic-styrene emulsion.

• KIEE International Transactions on Power Engineering
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• v.5A no.4
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• pp.322-330
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• 2005

This paper proposes methods to incorporate station related aging failures in composite system reliability assessment. Aging failures of station components, such as circuit breakers and bus bars, are a major concern in composite power system planning and operation as an increasing number of station components approach the wear-out phase. This paper presents probabilistic models for circuit breakers involving aging failures and relevant evaluation techniques to examine the effects of station related aging outages. The technique developed to incorporate station related aging failures are illustrated by application to a small composite test system. The paper illustrates the effects of circuit breaker aging outages on bulk system reliability evaluation and examines the relative effects of variations in component age. System sensitivity analysis is illustrated by varying selected component parameters. The results show the implications of including component aging failure considerations in the overall analysis of a composite system.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1114-1123
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• 2015

Bushing is the key link to connect outer and inner insulating systems and also the essential electric accessory in electric power system, especially in the high voltage engineering (AC 1000kV, DC 800kV). This paper presented the experimental research of thermal aging characteristic of oil-paper insulation used in bushing. A thermally accelerated aging experiment at 90℃ was performed. The bushing models containing five layers of paper were sealed into the aging vessels and further aged for 250 days. Then several important parameters associated with the aging were observed and evaluated. The results showed that the degree of polymerization (DP) of papers gradually decreased. The DP values of outermost layer and middle layer fit well into the second-order kinematic model and first-order kinematic model, respectively. Less deterioration speed of the inter-layer paper than outer layer was confirmed by the variation of DP. Hydrolysis was considered as the main cause to this phenomenon. In addition, the logarithm of the furfural concentrations in insulation oil was found to have good linear relationship with DP of papers. Interestingly, when the aging time is about 250 days and DP is 419, the aging process reaches an inflection point at which the DP approaches the leveling off degree of polymerization (LODP) value. Both tanδ and acid number of oils increased, while surface and volume resistivity of papers decreased. The obtained results demonstrated that thermal aging and moisture absorbed in papers brought great influence to the degradation of insulating paper, leading to rapid decrease of DP and increase of the tanδ. Thus, the bushing should be avoided from damp and real-time monitoring to the variation of tanδ and DP values of paper is an effective way to evaluate the insulation status of bushing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.406-409
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• 2002

The primary insulation system used in an oil-filled transformer is Kraft paper, wood, porcelain and, of course, oil. Modern transformers use paper that is chemically treated to improve its tensile strength properties and resistance to aging caused by immersion in oil. These insulation papers are mainly aged to thermal stress. Over the course of the insulation paper and oil's life it is exposed to high temperatures, oxygen and water. Its interaction with the steel of the tank and core plus the copper and aluminium of the windings will eventually cause the chemical properties of the oil to decay. High temperature have an effect on mechanical strength of cellulous paper using the layer insulation. We made two aging cell in which thermal aging tests of insulation papers and mineral oil are conducted. It is measured dielectric strength, number of acid, moisture, etc. of insulation paper and oil aged in the aging cells.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.4
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• pp.599-614
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• 2017

With the increasing media representation of aging as negative and abnormal, anti-aging products and discourses are spreading to younger generations. This paper analyzes the anti-aging discourse in a fashion magazine targeted towards women in their 20s. It quantitatively analyzes the historical development of the antiaging industry and discourses from 1994 to 2014 in the magazine "$C{\acute{e}}ci$". It also analyzes the patterns of signification associated with aging in the magazine through the use of critical discourse analysis. This paper identifies five major discourses -"segmentation of the definitions of youthful appearance", "scientific and medical discourse", "self-care discourse", "prevention of aging", and "social values of youthful appearances". The paper finds that the construction of anti-aging discourses towards women in their 20s is heavily influenced by the close link between the anti-aging industry and the fashion media. It also confirms the ideology of self-development though a rigorous appearance-management that is strongly imposed on Korean women and subsequently reproduced in an anti-aging discourse towards women in their 20s.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.11-16
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• 2011

This study was carried out in order to elucidate the effect of latex dosage and properties on aging behavior of coated paper. The coated paper with five different coating formulations were prepared and also four different latices were used. The coated paper were thermally aged at $105^{\circ}C$ for 14 days and the optical properties were measured. Increasing latex content increased the magnitude of reduction in brightness and whiteness. In addition, the variations in CIE a$^*b^*$ were larger with increasing latex dosage. Latex which has the lower gel content and the higher Tg showed the higher reduction in brightness and whiteness and much variation in CIE a$^*b^*$. However the particle size of latex didn't affect to thermal behavior of coated paper. These results indicate that latex which has higher Tg and lower gel content is the one of the main factors affecting aging behavior of coated paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.693-699
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• 2010

General transformer's life is known as paper insulation' life. If a transformer is degraded by these aging factors, it is known that electrical, mechanical and chemical characteristics for transformer's oil-paper are changed. When the kraft paper is aged, the cellulose polymer chains break down into shorter lengths. It causes decrease in both tensile strength and degree of polymerization of paper insulation. The paper breakdown is accompanied by an increase in the content of furanic compounds within the dielectric liquid. In this paper it is aimed at analysis on correlation between aging characteristics for insulating diagnosis of thermally aged paper. For investigating the accelerated aging process of oil-paper samples accelerating aging cell was manufactured for estimating variation of paper insulation during 500 hours at $140^{\circ}C$ temperature. To derive the results, it was performed analysis such as tensile strength(TS), depolymerization(DP), dielectric strength(DS), relative permittivity, water content(WC) and furan compound(FC) for aged paper. Also for analyzing correlation between insulating degradation characteristics, we used linear regression method. As as results of linear regression analysis, there was a close correlation between TS and DP. WC, FC. But dielectric strength was a weak correlation with aging time.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.3
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• pp.36-41
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• 2008

It is known that ethanolamines play a critical role for deacidification of paper sized by alum-rosin. However, amines also are effective as a chelating agent of metal. The present work was focused on whether amines could scavenge metals and prevent from the aging of paper. Metals such as alum, copper(II) and iron(III) was added to paper, and the paper treated with amines was aged in a thermo-hygrostat for 3-6 days. In the case of paper added to alum, the amines efficiency against paper aging was good in the oder of triethanolamine, diethanolamine and monoethanolamine attributable to the intensity of basicity and steric effect. Even in the case of paper treated with copper(II) chloride, iron(III) chloride, and copper(II) chloride, the significant preservation efficiency was shown by ethanolamine during accelerated aging. This outcome pinpoints the fact that ethanolamine can prevent paper aging not only from acid by neutralizing acid contained in paper but also from metals by producing of complexes with metals. These consequences above convince that ethanolamine makes it possible for mass deacidification for paper which contains acid and metals. Future studies should be conducted concerning whether, in reality, the treatment of its gas mode, in a single or multiple applications, has significant effect on lessening paper aging.