• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.264-271
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• 2005

Sand pile method, such as sand drain method and sand compaction pile method, has been popularly used as an improvement method for soft clay grounds. The effect of accelerating consolidation of soft clay grounds has been evaluated with Barron's solution. By the way, the consolidation behavior of soft clay ground with sand piles strongly depends on both the nonlinear mechanical interaction between sand piles and surrounding clays and the degradation permeability of clays. In this paper, the method for determining consolidation parameters of soft clay ground with sand drains by using Barron's solution was proposed, through a series of numerical simulations. Through the method, the change in both volume compressibility and permeability during consolidation was reasonably evaluated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 제2회 학술대회 논문집 일렉트렛트 및 응용기술전문연구회
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• pp.73-76
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• 2000

Traction motors that is one of the rotating machines for urban transit EMU have been subjected to increased demand for higher operating temperature, more demanding duty cycles, higher starting current, frequent voltage transients and severe environmental exposure. With the advent of PWM drives using power IGBTs in addition to the thermal considerations, it is important to take into account the impact of the dielectric stress upon the winding insulation system life. In analyzing the life of the stator winding, which is the heart of the motor, the majority of all winding failures are usually caused by a combination of various stresses acting on the insulation materials and system. In this paper, to evaluate the expected life of traction motor for urban transit E.M.U. it is proposed a new test method of complex accelerating degradation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.69-70
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• 2017

In Korea, silicone type sealant is widely used for construction site. Before the silicone type, urethane type is one of the main type sealants. However, the weathering property is less than the silicone type, the urethane type is replace by the silicone one. Still the urethane type is used for the inside of the buildings for the perimeter of the window. The silicone type sealants are better in weathering property than those of the urethane type sealants. Except the weathering property urethane type sealant has its own advantage like movement property, low cost and so forth. There are many research results for the outdoor weathering of the sealants, but in Korea there are no results for the outdoor weathering for construction sealants. This research is focused on the outdoor weathering of the urethane sealants, how to measure the degradation, and compare the products which used in Korea. The outdoor weathering test is usually time consuming, thus we designed specialized device for accelerating the result.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
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• pp.217-220
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• 2001

Fractal mathematics is being highlighted as a research method for classification of image. But the application of Fractal dimension(FD) has been required the complicated calculation method because of its complex repetition progressing. In this paper, it has been applied the new approach method to express FD for aging level calculation and investigated the relative degradation processing in outdoor EPDM insulator. As a result after testing, new proposed method has a capability to estimate in case of the field operated EPDM and accelerating test. Therefore, we find the differency of operated EPDM according to field condition.

• Preventive Nutrition and Food Science
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• 제4권2호
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• pp.103-106
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• 1999

Fish sauce is a liquid form of salt-fermented fish and has played an important role in Korean dietary life. Fish sauce was manufactured by utilizing Alaska pollack scrap from Himedara(seasoned and dried Alaska pollack tail) processing . In addition, the effects of squid viscera as a fermentation enhancer were also evaluate.Ph of Alaska plllack scrap sauce with squid viscera was lower than that of control over the entire fermentation process. Squid viscera acceleraged the production of amino-nitrogen, VBN , TBA and free amino acids, and the degradation of IMP and Inosine. The addition of squid viscera and koji at 5% concentration, respectively , also accelerated the digestion of Alaska pollack scrap and was similar to the results of squid viscera at 10% concentration.

• 유기물자원화
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• 제18권2호
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• pp.62-70
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• 2010

하수슬러지에 전자빔(3kGy)을 조사하여 퇴비화를 촉진하기위한 타당성연구가 수행되었다. 전자빔을 조사한 하수슬러지 탈수케익에 수분조절 및 탄소공급원으로 건조한 나뭇잎을 첨가하고 목편을 혼합한 퇴비단과 전자빔을 조사하지 않은 퇴비단(Control) 과의 시간에 따른 온도변화, 유기물 및 영양염류변화 그리고 미생물 활동도 차이 등을 비교평가하였다. 그 결과 전자빔조사한 하수슬러지퇴비단은 1일이내에 $60^{\circ}C$이상 온도가 상승하였고 Control 퇴비단에 비해 고온기간이 5일 이상 더 지속되었다. 또한 초기 5일 이내에 주발효기간 20일 동안 분해된 전체 유기물양의 70%가 분해되는 등 신속한 퇴비화가 진행되었으며, 퇴비화기간 내내 Control 퇴비단에 비해 DHAe-INT로 측정한 미생물 활동도가 높게 유지되어 전자빔 전처리에 의해 하수슬러지 탈수케익의 퇴비부숙이 신속하고, 효율적으로 이루어짐을 알 수 있었다.

• 한국미생물·생명공학회지
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• 제39권3호
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• pp.301-307
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• 2011

유류로 오염된 토양을 토양미생물 복원제를 첨가한 후 다양한 조건에서20일 동안의 유류저감효과를 알아보았다. 실험조건은 유류로만 오염된 토양(DS), 토양미생물 복원제를 20%(w/w)가 되도록 첨가한 유류로 오염된 토양(DSP), 토양 미생물 복원제를 넣은 후 pH를 중성으로 보정한 유류로 오염된 토양(DSP-1), 토양미생물 복원제와 촉진제를 넣은 유류로 오염된 토양(DSP-2), 토양미생물 복원제와 촉진제를 넣은 후 pH를 중성으로 보정한 유류로 오염된 토양(DSP-3)을 설정하였다. 실험 결과 pH를 보정한 토양미생물 복원제를 첨가한 유류오염토양은 탈수소 효소 활성과 TPH 저감에서의 효능이 우수하였다. 실험이10일 경과되었을 때 탈수소 효소 활성이 가장 높은 DSP-1 토양이 TPH 역시 가장 활발히 분해했다. 결과적으로 초기 10일의 배양기간 동안 토양미생물 복원제를 첨가한 토양은 대조군에 비해 38% 가량의 TPH 저감상승효과를 볼 수 있다. 토양미생물 복원제의 첨가를 통해 초기 저감속도를 올려줄 수 있으며, 최종적으로도 비 첨가군에 비해 높은 저감효율을 기대할 수 있다. 토양미생물 복원제를 유류오염토양을 복원한다면 초기 오염물질을 빠르게 처리할 수 있지만 미생물 활성은 pH, 온도 등 환경 인자에 많은 영향을 받으므로 토양미생물 복원제의 효율을 최대화하기 위해서는 환경 인자를 분석하여 이를 바탕으로 복원을 진행한다면 오염물질 정화 효율을 향상시킬 수 있을 것이다.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.999-1008
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• 2023

Deformed fuel rods can cause a partial blockage of the flow area in a subchannel. Such flow blockage will influence the core coolant flow and further the core heat transfer during the reflooding phase and subsequent severe accidents. Nevertheless, most of the system analysis codes simulate the accident process based on the assumed flow blockage ratio, resulting in inconsistencies between simulated results and actual conditions. This paper aims to study the influence of flow blockage in severe accident scenario of the CAP1400 reactor. First, the flow blockage model of ISAA code is improved based on the FRTMB module. Then, the ISAA-FRTMB coupling system is adopted to model and calculate the QUENCH-LOCA-0 experiment. The correctness and validity of the flow blockage model are verified by comparing the peak cladding temperature. Finally, the DVI Line-SBLOCA accident is induced to analyze the influence of flow blockage on subsequent CAP1400 reactor core heat transfer and core degradation. From the results of the DVI Line-SBLOCA accident analysis, it can be concluded that the blockage ratio is in the range of 40%-60%, and the position of severe blockage is the same as that of cladding rupture. The blockage reduces the circulation area of the core coolant, which in turn impacts the heat exchange between the core and the coolant, leading to the early failure and collapse of some core assemblies and accelerating the core degradation process.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권5호
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• pp.302-309
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• 2000

The tracking characteristics of silicone rubber degraded by accelerated outdoor exposure employing a weather-o-meter were investigated. The tracking test was performed according to ICE Publ.587 method but the concentration of conductive solution was two times higher than IEC standard in order to accelerate the tracking failure. The number of large effective scintillation and the current of high voltage circuit were measured simultaneously. It was shown that the number of effective scintillation had valuable information of the tracking degradation state of silicone rubber, while the average current between electrodes could not provide information enough for diagnosis. Based upon the experimental results, it could be said that the key factor accelerating tracking failure was not Joule heating by current but pyrolysis by burning of silicone rubber, and that reduction of contact angle was due to chain scission which resulted in the free radicals of low molecules.

• 한국건축시공학회지
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• 제7권4호
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• pp.109-116
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• 2007

Building structures are generally large in size and have a long life, and the construction of such structures requires the investment of a huge amount of money and social infrastructure. Furthermore, building structures are closely related to people's life. Recently, however, the rapid development of society has been worsening air pollution, which is in turn accelerating the degradation of building structures. Thus, the safety of building structure is emerging as a critical issue. To cope with this problem, the government enacted "The Special Act on Safety Control for Infrastructure" but we need engineers' higher concern over the maintenance and reinforcement of existing structures. Recently researches are being made actively on repair mortar using ultra rapid hardening cement for recovering the performance of structures. The present study conducted an experiment on the basic physical properties of ultra rapid hardening mortar for repairing and reinforcing building structures using magnesia cement and mono-ammonium phosphate. In the experiment, we changed the water-cement ratio and carried out replacement at different ratio of MAP/MgO(%). We used retarder to have working life, and made comparative analysis through evaluating working life and fluidity and measuring strength by age.