• Title, Summary, Keyword: Accelerated aging

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Longterm Aging Characteristics of Distribution Polymer Housed Surge Arresters by Multistress Accelerated Aging (복합 가속열화를 통한 배전용 고분자 피뢰기의 장기 열화특성 예측)

  • Kim, Ju-Yong;Kwon, Tae-Ho;Park, Chul-Bae;Kim, Joon-Eel
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.8
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    • pp.691-696
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    • 2007
  • In this study accelerated aging test equipment was developed to simulate domestic weather condition for accelerated aging test of polymer housed distribution surge arresters. Polymer arresters were aged for 3,000 hours by this test equipment and chemical and electrical characteristics analysis of surge arresters were conducted after aging test. In addition, performance assessment of outdoor installed arresters for 3 years was conducted to compare aging effect between accelerated aging test and natural aging. Through this experiment it is verified that the capability of the proposed aging test for simulating natural aging and the housing material and disconnector of domestic polymer arresters can be deteriorated by the long time field operation.

THE COLOR STABILITY OF AESTHETIC RESTORATIVE MATERIALS RESULTING FROM ACCELERATED AGING

  • Lee, Jeong-Seon;Suh, Kyu-Won;Ryu, Jae-Jun
    • The Journal of Korean Academy of Prosthodontics
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    • v.46 no.6
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    • pp.577-585
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    • 2008
  • STATEMENT OF PROBLEM: The discoloration of anterior teeth restoration is one of the material problems demanding retreatment. OBJECTIVES: To evaluate the color stability and affecting factors on esthetic restorative materials when subjected to accelerated aging. MATERIAL AND METHODS: This study was conducted using porcelain disks (IPS Empress 2-glazed, IPS Empress 2-polished), direct restorative resin disks (SYNERGY Duo) and indirect restorative resin disks (Sinfony, TESCERA ATL). Accelerated aging was done by precipitating the specimens in 38.C distilled water and irradiating with xenon light, and the total irradiation was 397.98 KJ/mm. Color and microhardness change of the specimens were measured before accelerated aging and after 100 hours, 200 hours and 300 hours of accelerated aging, and Surface of the specimens were examined with SEM before and after 300 hours of accelerated aging. RESULTS: 1. After 300 hours' accelerated aging, a ${\Delta}E$ value was 3.3 or lower in IPS Empress 2-glazed, IPS Empress 2-polished and Sinfony. 2. After 300 hours' accelerated aging, gloss was lost and surface changes including microcracks were observed in TESCERA ATL and SYNERGY Duo, and color changes of them ranged between 3.58 and 6.40 ${\Delta}E$ units. 3. During 300 hours' accelerated aging, the microhardness of surface was increased by 3.21 - 19.64% in all kinds of composites resin. CONCLUSION: After 300 hours' accelerated aging, SEM images IPS Empress 2-glazed, IPS Empress 2-polished and Sinfony showed little morphological change and their color changes were considered to be clinically acceptable. And there was significant correlation between microhardness changes and color changes of composites (P < .05).

Accelerated Thermal Aging Measurement and Analysis of CSPE Cable for Condition Monitoring (CSPE 케이블의 상태감시를 위한 가속열화 측정 분석)

  • Park, Joung-Ho;Cha, Wang-Cheol;Lee, Jung-Hoon;Cho, Uk-Rae;Kim, Jae-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.3
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    • pp.88-95
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    • 2015
  • The accelerated thermal aging of CSPE(Chloro Sulfonate Polyethylene) was carried out for 40.41, 121.22, 202.04 days, 16.82, 50.45, 84.09 days and 7.32, 21.96, 36.59 days at 100, 110, and $120^{\circ}C$, respectively, which are equivalent to 20, 60, 100 years of aging at $50^{\circ}C$. The permittivities and the apparent densities of the accelerated thermally aged CSPE samples are increased with accelerated thermal aging year but EAB(Elongation at Break) is decreased with that. The dielectric strength and the electric breakdown of the non-accelerated and accelerated thermally aged CSPE samples do not depend on accelerated thermal aging year and applied voltage rising time. density and EAB measures.

Reliability Assessment of Polymer Insulators by Accelerated Aging Test (가속열화시험에 의한 폴리머애자의 신뢰성 평가)

  • Han, Jae-Hong;Lee, Byung-Sung;Jung, Jong-Wook
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.10-14
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    • 2001
  • In order to assess the long-tenn reliability of polymer insulators for distribution power systems, we have developed the accelerated aging test method which can simulate the operation conditions. In this study, 3000 hours aging test for 4 kinds of polymer insulators has been completed by the developed accelerated aging test. After 3000 hours aging test, visual inspection and electrical tests were carried for identifying a change of characteristics. Some specimens showed the surface erosion and the manufacturing defect. In the electrical tests, the wet flashover voltage was significant1y decreased by the accelerated aging test. In comparison with the field-aged polymer insulators, it can be concluded that the developed test method can evaluate the long-tenn reliability within short time and screen the manufacturing defect.

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Early Germination Response of Soybean Seed to Accelerated Aging and Low Dose Gamma Irradiation

  • Hwangbo, Jun-Kwon;Kim, Jae-Sung;Lim, Ji-Hyeok;Baek, Myung-Hwa;Chung, Byung-Yeoup;Kim, Jin-Hong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.49 no.1
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    • pp.25-29
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    • 2004
  • The responses of soybean seeds were evaluated to accelerated aging and gamma irradiation with regard to germination, seed leakage, seed leachate component and dry weight of hypocotyl and primary root of the germinating seed. Accelerated aging significantly reduced the final germination rate while gamma irradiation increased the final germination rate. Furthermore, the interactive effects occurred that the final germination rate of 5-day aged seeds increased considerably in response to 4 Gy of gamma irradiation. The extent to which the electrolyte was leaked from the seeds (conductivity) was significantly affected by accelerated aging and showed a close negative correlation with the germination rate. Gamma irradiation, however, did not significantly affect the electrical conductivity of seed leachate. The accelerated aging significantly increased the concentrations of the particular electrolytes leaked from the seeds while the gamma irradiation did not affect those concentrations. Of the electrolytes leaked from the seeds, Ca and Mg showed relatively lower concentrations while K showed greater concentrations than others. Moreover, N and P showed similar responses to aging treatment. Aging treatment significantly affected dry weight (DW) of hypocotyls and primary root. Also, gamma irradiation decreased DW of hypocotyls and primary root, particularly for 8 Gy associated with 5 days aging treatment. The data were discussed in terms of the relationships of seed vigor with aging treatment and gamma irradiation.

Analysis of Influence for High Frequency voltage Accelerated Aging of XLPE Cable (고주파 전압이 XLPE cable의 가속열화에 미치는 영향 분석)

  • Kim, We-Young;Hu, Jong-Chul;Yun, Dae-Hyuk;Park, Tae-Gone
    • Proceedings of the KIEE Conference
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    • pp.1670-1672
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    • 2004
  • XLPE compound have used for insulation of 22.9kV power cable. XLPE insulation is aged for use long time in distribution line. The cause of aging is water tree is happening and growth. Accelerated water tree test method are Accelerated volatge aging method and high frequency aging method. In this paper, high frequency accelerated water tree was performed. And the result was analysed AC breakdown voltage and size and number of water trees.

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COLOR STABILITY OF CURRENT PROSTHETIC COMPOSITES UNDER ACCELERATED AGING AND IMMERSION IN A COFFEE SOLUTION

  • Kim, Hyo-Jin;Heo, Seong-Joo;Koak, Jai-Young;Chang, Ik-Tae
    • The Journal of Korean Academy of Prosthodontics
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    • v.40 no.3
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    • pp.225-235
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    • 2002
  • The color stability of current prosthetic composites is unknown, even though the quality of composite materials has been improving. This study examined the intrinsic color stability of various current prosthetic resins (ceramic-polymers) after an accelerated aging process and the extrinsic color stability after immersion in a coffee solution. By comparing the amount of discoloration after aging with that without aging, the effect of the accelerated aging process on external discoloration could be evaluated. Three current prosthetic composites (Artglass, Targis, Sculpture), one light polymerized direct composite (Z100) and one dental porcelain control (Ceramco) were assessed. The color changes (${\Delta}$E) of all the specimens were determined using the CIE $L^{*}a^{*}b^{*}$ color order system with a reflected spectrophotometer. The results were as follows: 1. The prosthetic composite materials subjected to the accelerated aging test showed no significant difference in color changes (p >.05). 2. In the coffee solution immersion test after the aging process, the color changes of the Targis and Artglass groups were not different from that of the Z100 group, which showed the highest color change. 3. In the immersion only test, a significantly high color change was observed in the sculpture glazing group. 4. The aging process influenced on the color changes more in the Targis, Artglass and Z100 groups than in the Sculpture and Ceramco groups.

A Study on Validation of Condition Monitering Method of Accelerated Thermal Aging CSPE (가속열화 된 CSPE 상태감시법의 유효성 연구)

  • Shin, Yong-Deok;Goo, Cheol-Soo;Kim, In-Yong;Lee, Jung-Hoon
    • Proceedings of the KIEE Conference
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    • pp.1447-1448
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    • 2011
  • The CSPE cables are used for three years in nuclear power plant. The accelerated thermal aging of chloro sulfonate polyethylene(CSPE) jacket of test cables were carried out for the period equal to 10, 20 and 30 years in air at 90 and $100^{\circ}C$, respectively. The electrical volume resistivity, density, XPS, FE-SEM, EDS and XRF of the accelerated thermal aging of CSPE were measured. The validation of condition monitering method of accelerated thermal aging CSPE was estimated by them. The best validation of condition monitoring method of accelerated aging CSPE is electrical volume resistivity because change thermal of the specimen showed distinction.

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A Study on Suitable Condition of Accelerated Aging Test and Evaluation Criteria of Data Stability for Archival Performance Analysis of BD-R media (BD-R 장기보존 특성 평가를 위한 가속 열화 실험 조건과 안정성 평가 기준에 관한 연구)

  • Lee, Kwan-Yong;Park, Sun-Joo;Kim, Do-Hyun;Jo, Yi-Hyung;Kim, Young-Joo
    • Transactions of the Society of Information Storage Systems
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    • v.10 no.1
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    • pp.7-13
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    • 2014
  • The Blu-ray Disc Recordable(BD-R) is one of strong candidates for archival application among optical media formats, because of its large capability. However, the well-defined accelerated aging test conditions and evaluation criteria have not yet been fully confirmed for BD-R. In this study, the data stability and degradation aspect of BD-R were analyzed by the random-symbol error rate(R-SER) measurement after the accelerated aging test. And a reasonable test condition of accelerated aging for BD-R and the appropriate evaluation criterion using R-SER measurement were discussed.

Dissolved Gas Analysis of Environment-Friendly Vegetable Insulating Oils (친환경 식물성 절연유의 유중가스 분석)

  • Choi, Sun-Ho;Kim, Kwan-Sik;Huh, Chang-Su
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.4
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    • pp.238-243
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    • 2015
  • The vegetable insulating oils are substitute for the mineral oil in power transformer. Vegetable insulating oils has higher flash/fire point and biodegradability than conventional mineral oils. In this paper, we investigated the dissolved gas analysis of vegetable oils. In the experiment, I had to accelerated aging under the same conditions mineral oil and vegetable oils. Accelerated aging proceeded to about 100% of the life of oil-filled transformer. In addition, we performed gas analysis of insulating oil of accelerated aging progress. The experiment results of the five gases was measured with the exception of Hydrogen and Acetylene. The mineral oil and vegetable oils gas is generated in a similar tendency depending on the accelerated aging. As a result, vegetable oils, can be dissolved gas analysis by method such as mineral oil.