• Journal of Korea Foresty Energy
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• v.21 no.2
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• pp.34-42
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• 2002

This research was carried out to investigate water repellent effectiveness of natural oil treated wood. Linseed oil, castor oil, olive oil, bean oil, perilla oil and sunflower oil were used in this test. For evaluation of water repellent of natural oil treated wood, moisture absorption test, water-drop contact angle test and color difference test of accelerated decomposition by UV and water were used. The moisture absorption amount of natural oil treated wood was less than untreated wood until 3 hours, but it was increased with time, there was no big difference with oil treated wood and untreated wood after 48hours. Oil treated wood and untreated wood showed big difference on contact angle test. It was no big difference by kind and oil concentration. Natural oil treated wood did not showed stability on the weather aging test. Contact angle test could be used on evaluation of wood surface status treated with natural oil.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.2
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• pp.184-189
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• 2014

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.9
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• pp.867-873
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• 2010

The failure of water-cooled generator stator windings as a result of insulation breakdown due to coolant water leaks and water absorption often occurs worldwide. Such failure can cause severe grid-related accidents as well as huge economic losses. More than 50% of domestic generators have been operated for over 15 years, and therefore, they exhibit signs of aging. Leaking and water-absorbing windings are often found during an overhaul. In an existing method for evaluating the integrity of generator stator windings, the drying process of the interior of the windings is ignored and only final leak tests are performed. In this study, it is shown that water leaks and water absorption in stator windings can be detected indirectly through vacuum pattern analysis in the vacuum drying mode, which is the used in the preparation stage of the leak test.

• The Korean Journal of Applied Statistics
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• v.22 no.5
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• pp.961-969
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• 2009

Water absorption in water-cooled generator stator windings can cause serious accidents such as insulation breakdown and it brings a generator to the unexpected sudden outage. Accordingly, it is important to diagnose the water absorption of them in the effective operation of power plant. Especially, the capacitance value which is measured for diagnosis is very small so the special diagnosis methods like stochastic theory are needed. KEPRI developed the water absorption test equipment and diagnosis technology for them. In this paper we propose that water absorption test of generator stator windings using probability distributions. The proposed diagnosis technology is applied to the real system and the results of water absorption test for stator windings are agreed to them of water leak test.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2033_2034
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• 2009

고전압회전기 고정자권선 절연물의 일반적인 운전조건에서 나타나는 열화특성은 많은 연구결과를 바탕으로 발전되어 왔다. 특히 고정자권선 절연물이 습한환경에서 운영되었을 경우 일반적인 절연물의 열화특성과는 다른것을 알 수 있다. 본 논문에서는 이러한 흡습특성에 대해 실제 산업현장에서 운영중인 고전압전동기 권선 절연물에서 나타나는 절연특성을 분석하고자 하였다. 이를위해 습한환경에서 운영중인 전동기를 선정하여 절연특성시험을 실시하였고 직류 및 교류시험전압결과에서 절연물의 흡습상태에 따른 고유의 절연특성결과값을 얻을 수 있었다.

• 열병합발전
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• s.58
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• pp.8-13
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• 2007

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.139-145
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• 2016

In this study, the moisture related hygroscopic characteristics and mechanical properties of epoxy-clay nanocomposites were investigated by experiments as a function of the weight fraction of nanoclay. The hygroscopic and mechanical properties including the moisture saturation amount, moisture diffusivity, adhesive strength, and tensile properties were obtained by moisture absorption test and various tensile tests, respectively. Also, the molecular dynamics (MD) simulation was devised to study of hygroscopic characteristics of nanocomposites and the results were compared to experimental results as a function of the nanoclay content. It was demonstrated that the proposed MD simulation technique can be successfully used for the prediction of the effects of the nanoclay on the moisture diffusion characteristics.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.6
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• pp.107-113
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• 2023

In the field of ammunition, storage performance is recognized as important, and the moisture-proof performance of packaging containers is very important. In the ammunition field, paper cans with a multi-layered structure are mainly used as packaging containers. It is made by layering materials that play various roles. These packaging containers are mainly evaluated for moisture-proof performance according to the Korean Industrial Standard KS T 1314. The moisture permeability is determined through linear regression analysis of the change in weight of the moisture absorbent added inside. In this study, the effect of the amount of desiccant added on the moisture permeability test results of packaging containers was confirmed. It is considered appropriate that the amount of desiccant used in testing ammunition packaging containers be approximately 70% or more of the internal volume.

• Composites Research
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• v.12 no.1
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• pp.19-27
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• 1999

A design development test for carbon/epoxy composite laminates for an aircraft flight control system is performed. The design development test includes moisture absorbing test, tensile, compressive, bearing and lap shear tests. The moisture absorbing behavior for different fiber orientation angles is investigated and the changes in mechanical characteristics are compared. In the in-plane tensile test, the effect of damages such as scratches and impacts is studied. The bearing test is performed for different fastening types. The resulting design allowable stress and environmental load enhancement factor are used for the structural analysis and certification tests for the flight control system.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3059-3066
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• 2008

It is reported that the life of generator stator windings is expected about 30 years and a leak and water absorption phenomena can be progressed by fatigue, vibration, and corrosion. The water-cooled generator stator windings which were operated over 15 years are over 20 units and the mechanical problems such as leak and water absorption were found in the generator stator windings. In this paper, the systematic mechanical integrity evaluation methods which are applied to the water-cooled generator stator windings within the country are introduced.