• 펄프종이기술
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• 제38권3호
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• pp.23-28
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• 2006

Xylan in hemicellulose has been reported as one of the reasons of the yellowing of chemical pulp and paper. But little relevant information is available in literature. In this study, we examined into the influence that glucuronoxylan or glucomannan and metallic ion($Cu^{2+},\;Fe^{2+},\;Fe^{3+},\;Mn^{2+}$) residued in pulp get each or when mixed at yellowing. Filter paper was treated with each metallic ion, glucuronoxylan and the mixture of glucuronoxylan and metal ions, and brightness and CIE $L^*a^*b^*$ was measured after accelerated aging. As the results of measurements, the filter paper processed by 10% glucuronoxylan was dropped $2{\sim}3%$ on the brightness after accelerated aging for 24 hours. Also, the filter paper treated with glucuronoxylan and $Fe^{2+}$ was dropped 7% on the brightness.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.86-89
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• 2004

Recently polymer arresters are being used widely but we don't have appropriate long term characteristics test methods. Therefore we need to develop special test facility to evaluate long term reliability of polymer arresters. It's polymeric housing can be degraded by environmental stress and the interface between housing and inner module can be affected by moisture absorption. This moisture absorption can cause leakage current and tracking in the interface. We developed multi stress accelerated ageing test facility to simulate field conditions including UV, temperature, humidity, voltage, salt fog and rain. In addition, we carried out field exposure test at the outdoor test yard and characteristics analysis of field operated specimens to evaluate accelerating factor of this accelerated aging test.

• 한국추진공학회지
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• 제23권3호
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• pp.51-57
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• 2019

HTPB 고체 추진제 기계적 물성의 후경화 효과에 대하여 시편 시험을 통하여 평가하였다. 후경화 반응 완료 후 시편 가속노화 시험을 실시하여 Arrhenius 식의 계수를 획득하였다. 확인을 위하여 원통형 모사 충전체를 설계, 제작하여 가속노화 시험을 수행하였으며, 시험 후 추진제 표면 부위, 중앙 부위, 접착 부위에 대하여 시편을 채취하여 노화 물성을 평가하였다. 측정된 결과에 대하여, 획득된 가속노화 식으로 예측하여 비교하였다. 그 결과 JANNAF 시편 시험을 통한 가속노화 식은 추진제 재료의 노화를 잘 예측하였으나 접착 부위에서는 실제 측정 결과와 차이를 나타내었다. 따라서 실기형 추진기관에서 노화 시료를 채취하는 경우 시험 목적에 부합하도록 시편 채취 부위를 선정해야 한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.402-403
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• 2009

Accelerated aging tests were conducted under laboratory conditions on two generator stator bars. Electrical stress is applied in No. 1 model stator bar. Electrical and thermal stresses are applied in No. 2 model stator bar. As aging times increased from 0 to 11460h, dissipation factor($tan{\delta}$) test was performed on No. 1 and No.2 model stator bars. The ${\Delta}tan{\delta}$ of No. 1 and No. 2 stator bars increased with increased in aging time.

• 전기학회논문지
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• 제58권7호
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• pp.1375-1379
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• 2009

Insulation tests have been performed on two generator stator bars under accelerated aging under a laboratory environment. Electrical stress was applied to stator bar No.1, and electrical and thermal stresses were applied to stator bar No.2. Nondestructive stator insulation tests including the ac current, dissipation factor($tan{\delta}$), and partial discharge tests have been performed on both bars as the bars were aged for 11460 hours. Experimental test results show that ${\Delta}I$, ${\Delta}tan{\delta}$, and partial discharge of No. 1 and No.2 stator bars increased with increased in aging time. It has been concluded from the test that the stator insulation of the two generators are in good condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1343-1344
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• 2006

There have been numerous accelerated aging laboratory tests for evaluating suitability of polymeric materials and devices. Aging test for materials and its full scale device has been conducted. Service experience plays a key role in the utility section of composite insulators. A meaningful and reliable accelerated aging test is needed for evaluating composite insulator. During the service these insulators are subjected to aging stress such as humidity, pollution, and electrical field, and erosion and tracking of the weathershed occurs. This paper presents the criteria of reliability evaluation and evaluation facilities for 22.9 kV suspension composite insulator. We adopt the criteria of reliability evaluation consist of two test methods. One is CEA tracking wheel test for examining the tracking and erosion performance of composite insulator. The other is multi-stress aging test for examining effects of environmental factors such as UV, temperature, humidity, etc on composite insulator.

• International Journal of Automotive Technology
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• 제7권3호
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• pp.245-249
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• 2006

Accelerated aging of engine exhaust system components such as catalytic converters are traditionally performed using an engine/dynamometer test stand. $SwRI^{(R)}'s\;FOCAS^{(R)}$ system reduces or eliminates many of the engine based aging limitations. This paper will describe several studies. These include: 1) replication of engine based catalyst aging cycles with added precision and dependability; 2) catalyst aging with and without lubricating oil effects; 3) effects of lubricant phosphorus on catalyst performance; and 4) the potential to thermally age components beyond the capabilities of engine based systems. The first study includes the development of the SwRI FOCAS system to run programmed aging conditions with or without lubricating oil. A description of the subsystems is given. The second two studies used the SwRI FOCAS system to age catalysts. One study compared thermal-only aging using of the SwRI FOCAS system with equivalent aging on a traditional engine/dynamometer test stand. The other study examined the effect on catalyst performance of two lubricating oils containing different levels of phosphorus, and compared the results to field data generated using the same oils in a fleet of vehicles.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1136-1137
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• 2015

The accelerated thermal aging of chlorosulfonated polyethylene (CSPE) was performed for 0 days, 80.82 days, and 161.63 days at $100^{\circ}C$, which is equivalent to 0y, 40y, and 80y of aging, respectively, at $50^{\circ}C$. The volume electrical resistivity of dried CSPE for 570~630 days after seawater and freshwater soaking, are $1.109{\times}10^{14}{\Omega}{\cdot}cm$, $8.546{\times}10^{13}{\Omega}{\cdot}cm$ and $8.466{\times}10^{13}{\Omega}{\cdot}cm$. The applied voltage rising time of 11~12 second and dielectric breakdown time of 9~11 second of the accelerated thermal aged CSPE is shorter than those of 12~13 and 11~13 second of the non-accelerated thermal aged CSPE, respectively. It is shown that oxidation, fragment and crack are formated at hole of dielectric breakdown in CSPE. The apparent density of dried CSPE for 750 days are $1.555g/cm^3$, $1.595g/cm^3$ 및 $1.597g/cm^3$ according to accelerated thermal aging year, respectively.

• 한국산림과학회지
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• 제99권2호
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• pp.244-250
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• 2010

The aim of this study was to investigate relationship among seed viability and enzymes activities involved in scavenging reactive oxygen species (ROS), especially, superoxide dismutase (SOD), glutathione reductase (GR), and catalase (CAT). In other respects, osmopriming has been demonstrated to reinvigorate aged seeds. Various viabilities of seeds that were ranged from 80 to 100% of germination rate could be produced using osmopriming and accelerated aging treatments. Priming treatment of Pinus thunbergii seeds for 3 days at $15^{\circ}C$ with a polyethylene glycol solution at -1.2 MPa improved their subsequent germination at $25^{\circ}C$. Accelerated aging (3, 6, 9, and 12 days at $41^{\circ}C$ and 100% relative humidity) decreased seed germination percentage depending on aging treatment duration. Electrolyte conductivities of seeds were measured as assay of membrane integrity. The conductivity from electrolyte leakage of P. thunbergii seed was also correlated with seed germinability. Conductivity for control seeds that had 95% of germination percentage was 3.48 ${\mu}S\;g^{-1}$, but jumped as doubled (7.98 ${\mu}S\;g^{-1}$) in 12-day-aged seed that had 80% of germination percentage. Our results demonstrate that aging of P. thunbergii seeds is associated with changes in the electrolyte leakage, lipid peroxidation, and antioxidant defense system. Priming of aged seeds progressively restored the initial germinative ability and resulted in a marked decrease in the levels of MDA and conductivity of seed leachate. These effects of priming were also well recovered of GR and CAT activities in aged seed. The improved seed quality by priming treatment appears at least partly attributable to reduced lipid peroxidation, resulting from enhanced antioxidative enzyme activities that are suggesting the antioxidant defense systems play a key role in seed vigor.

• 한국작물학회지
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• 제48권1호
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• pp.13-16
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• 2003

Seeds of burcucumber were treated with accelerated aging, cold-stratification, and light quality illuminated during desiccation to enhance their germination and seedling emergence. The germination was increased by aging and cold-stratification although the latter treatment showed greater effectiveness than the former one. In the combined treatment of aging 6 days at $45^{\circ}C$ and cold-stratification, the germination was promoted under longer period of cold-stratification to reach nearly 100% in 3 week cold-stratification on the ninth day from sowing. In the sequentially combined treatment of aging, cold-stratification, and light quality during 24 hour desiccation at $35^{\circ}C$, no-stratified seeds showed the highest rate in red light treatment but the lowest in far-red light. This implies that the phytochrome action run during the desiccation of imbibed seeds. The red light exposure during drying for the cold-stratified seeds after aging accelerated the germination even more than the dark treatment and germinated 100% on the next day of sowing. It is concluded that the sequential treatment of aging, cold-stratification, and red light illumination during desiccation can highly promote percentage and speed of burcucumber seed germination.