• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.121-129
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• 2012

The edge area with burn severity is known as significant factor that has great effects on the ecosystem recovery. However, there is little study on the edge area and its effects in the South Korea. Thus, this study aimed to analyze immediate responses of vegetation following forest fires due to combined effect of burn severity and edge-interior effect. Burn Severity (BS), or ${\Delta}NBR$ values were computed using satellite images of pre and post-forest fire in Samcheock areas. The burn forest was classified 231 $1-km^2$ girds and these grids were further reclassified into 4 groups by BS type (low BS and high BS areas) and forest areas (edge areas and interior areas). These four groups of grids including low BS-interior (group A), low BS-edge (group B), high BS-interior (group C) and high BS-edge (group D). Post-fire vegetation responses measured with (${\Delta}NDVI$) among four groups were then compared and tested by T-test. The results indicated that group C (${\Delta}NDVI$=0.047) and D (${\Delta}NDVI$ = 0.059) showed considerably greater vegetation regeneration than those of low BS areas including group A (${\Delta}NDVI$ = -0.039) and group B (${\Delta}NDVI$ = -0.036). It was also observed that edges areas showed greater vegetation regeneration than interior areas when BS is the same. Group B (${\Delta}NDVI$ = -0.036) showed greater (${\Delta}NDVI$) values than group A (${\Delta}NDVI$ = -0.039) in low BS condition. Similar relationship is observed between group C and group D in high BS condition. Thus adequate restoration practices for burned areas might need to pay close attention to interior areas with low BS to minimize the secondary damages and to rehabilitate the burned forests.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.620-625
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• 2015

In an effort to reduce the onset of global warming, the International Maritime Organization Marine Environment Protection Committee (IMO MEPC) proposed the reduction in ship speeds as a way of lowering the proportion of carbon dioxide ($CO_2$) in the Green House Gas emissions from ships. To minimize fuel costs, shipping companies have already been performing slow steaming for their own fleets. Specifically, the slow steaming approach has been adopted for most ocean-going container lines. In addition, because of the increased marine fuel cost that is required to enable increased capacity, there is an urgent need for more advanced fuel-saving technologies. Therefore, in this present study, we propose a fuel-cost reduction method that can improve the performance of diesel engines. We introduce a predetermined amount (0.025% of the amount of fuel used) of fuel additive (oil-soluble calcium-based organometallic compound). For improved experimental accuracy, as the test subjects, we utilize a large two-stroke diesel engine installed in land plants. The loads of the test engine were classified as low, medium, and high (50, 75, and 100%, respectively). We compare the engine performance parameters (power output, fuel consumption rate, p-max, and exhaust temperature) before and after the addition of fuel additives. Our experimental results, confirmed that we can realize fuel-cost savings of at least 2% by adding the fuel additive in low load conditions (50%). Likewise, the maximum combustion pressure was found to have increased. On the other hand, we observed that there was a reduction in the exhaust temperature.

• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.129-133
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• 1982

This study was conducted to find out the resistance of rice varieties to ozone gas. Thirty eight rice varieties were exposed to 0.3 ppm $O_3$ gas for 3 hours. Damage symptom, percentage of destroyed leaf and chlorophyll contents were observed after $O_3$ fumigation. The results obtained are as follows. 1) Typical symptom of $O_3$ damage appeared to greyish subtle spots in Japonica type and redish brown subtle spots in Indica-Japonica hybrid type within rice leaf vein. 2) Resistant varieties to $O_3$ gas were Palgwangbyeo, Seokwangbyeo and Milyang 30, while sensitive ones were Gwanakbyeo, Jinjubyeo and Hankangchalbyeo. 3) Chlorophyll damage of rice leaves were higher in Nongbaeck, Dobongbyeo, Palgeum, Jinjubyeo than in Milyang 21, Podgwangbyeo, Josaeongtongil, Honamjosaeng, Hwanggeumbyeo. 4) The amount of chlorophyll damage showed highly significant positive correlation with that of leaf destruction.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.1
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• pp.87-93
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• 2006

Inventories, and characteristics such as dimension, fuel rod array, weight, $^{235}U$ enrichment, and discharge burnup of spent nuclear fuel (SNF) generated from existing and planed nuclear power plants based on National 2nd Basic Plan for Electric Power Demand and Supply were investigated and projected to support geological disposal system design. The historical and projected inventory by the end 2057 is expected to be 20,500 and 14,800MTU for PWR and CANDU spent nuclear fuel, respectively. The quantity of SNF with initial $^{235}U$ enrichment of 4.5 wt.% and below was shown to be 96.5% in total. Average burnup of SNF revealed $\sim36$ GWD/MTU and $\sim40$ GWD/MTU for the period of 1994-1999 and 2000-2003, respectively. It is expected that the average burnup of SNF will be $\sim45$ GWD/MTU at the end of 2000's. From the comprehensive study, it was concluded that the imaginary SNF with $16\times16$ Korean Standard Fuel Assembly, cross section of $21.4cm\times21.4cm$, length of 453cm, mass of 672 kg, initial $^{235}U$ enrichment of 4.5 wt.%, discharge burnup of 55 GWD/MTU could cover almost all SNFs to be produced by 2057.

• Journal of Technology Innovation
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• v.22 no.4
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• pp.145-164
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• 2014

Nuclear fusion is one of the most promising options for generating large amounts of carbon-free energy in the future. Major countries such as China, EU, and Japan have established a national plan for DEMO construction and they are implementing it. Korea has started a nuclear fusion research and development by the KSTAR project started in 1995. There are matured needs for a full-scale research and development initiatives to ensure competition with the major countries for DEMO as well as achieve the final goal to commercialize fusion energy. In this paper, we apply the TRL and AHP methods in order to identify the key technologies to conduct DEMO R&D. We propose the priorities of future R&D on DEMO by deriving a core technology in the field. At first, we review the scientific theory of fusion and trend of progress of DEMO activities in major countries. For previous studies, we review TRL and AHP methods to examine the technology classification system of DEMO and identify key technologies. We apply TRL method to identify readiness level of DEMO technologies and AHP to compensate shortcoming of TRL. The key technologies of DEMO to be secured from a synthesis result of the TRL and AHP are burning plasma, plasma facing material, structural material, high frequency heating, neutral particle beam, safety, plasma diagnostic, and simulation technologies.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.347-354
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• 2014

Economic evaluation of the manufacturing technology of high-value chemicals through the carbonation reaction of carbon dioxide contained in the flue gas was performed, and analysis of the IRR (Internal Rate of Return) and whole profit along the production plan of the final product was conducted. Through a carbonation reaction with sodium hydroxide that is generated from electrolysis and by using carbon dioxide in the combustion gas that is generated in the power plant, it is possible to get a high value products such as sodium bicarbonate compound and also to reduce the carbon dioxide emission simultaneously. The IRR (Internal Rate of Return) and NPV (Net Present Value) methods were used for the economic evaluation of the process which could handle carbon dioxide of 100 tons per day in the period of the 20 years of plant operation. The results of economic evaluation showed that the IRR of baseline case of technology was 67.2% and the profit that obtained during the whole operation period (20 years) was 346,922 million won based on NPV value. When considering ETS due to the emissions trading enforcement that will be activated in 2015, the NPV was improved to a 6,000 million won. Based on this results, it could be concluded that this $CO_2$ carbonation technology is an cost-effective technology option for the reduction of greenhouse gas.

• Journal of the Mineralogical Society of Korea
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• v.22 no.2
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• pp.153-162
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• 2009

The main compositions of "Seokganju", a Korean traditional red mineral pigment, are iron oxides. To investigate its mineralogical and functional properties, we had got its ore from Juto cave in Ulreoung island, which was a famous field of it in Korean documents. The ore occurs as a paleosol between the olivine basalt and amphibole trachyte in discontinuously. It is reddish brown and yellowish brown and consists mainly of clay minerals with minor debris. Its reddish and yellowish brown color are due to the hematite and ferrihydrate, respectively. These iron oxides are precipitated as ferrihydrate from the ferrous water in the paleosol and partly changed to hematite. The color reproduced in timber by using seokganju pigment with traditional tools and methods is similar to that in heritage building. The moistureproofing and fire resistance of Ulreungdo seokganju is far better than that of artificial seokganju. Moreover, the combustion tests show that the artificial seokganju promote the ignition and combustion of the timber. Ulreungdo seokganju is regarded as a pigment with fungicidal efficacy because growth of two wood decay fungi (cov. and typ.) are inhibited in solid medium with it.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.376-377
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• 2011

최근 Mg, Mg-Al합금, Al은 전자제품의 케이스, 차량의 휠 등의 신소재로서 활용성이 높아 사회적 수요가 급격히 늘고 있다. 이러한 수요 증가와 함께 관련 사업장에서는 취급 과정에서 폭발사고 위험성이 높아지고 있는데, 2010년도에는 국내 사업장에서 금속 분진에 의한 폭발사고가 4건이 발생하여 인명 및 재산피해가 발생하였다. Mg-Al합금의 폭발사고로 사망 1명과 부상 2명이 발생하였으며, Al분진의 폭발사고는 3건이 발생하여 사망 2명과 부상 3명의 인명피해로 이어졌다. 사고조사를 통하여 사업장에서의 금속분진에 대한 위험인식이 매우 낮은 것이 유사 사고가 반복되고 있는 가장 큰 이유로 알려지고 있는데, 이는 금속분진에 대한 부족한 안전기술정보와 밀접한 관련이 있다. 본 연구에서는 Mg, Mg-Al합금, Al등을 취급하는 관련 사업장에서 폭발사고 예방대책을 위하여 활용할 수 있는 폭발특성에 관한 안전기술정보 제공을 목적으로 하고 있다. 보다 구체적으로는 사고 다발 금속분진에 대한 위험성 이해에 도움을 될 수 있도록 동일 입경분포 조건에서의 위험성을 정량적으로 평가하였으며, 이를 위하여 각 금속분진의 동일 입경 조건에서 최대폭발압력, 폭발하한계 등의 폭발위험성 데이터를 실험적으로 조사 하였다. 조사한 시료는 평균입경 200 mesh의 Al, Mg, Mg-Al(60:40 wt%)로서 입도분석기(Beckman Coulter LSI 3320)를 사용하여 측정한 결과 평균입경은 약 $155{\mu}m$로 나타났다. Al분진의 농도변화에 따른 폭발압력을 조사한 결과, 최대폭발압력(Pmax)은 7.9 bar였으며 최대폭발압력상승속도 (dt/dP)max는 농도 $1500[g/m^3]$에서 322 [bar/s]로 최대가 되었으며 폭발 하한계(LEL)는 $70[g/m^3]$가 얻어졌다. 반면에 순수한 Mg의 LEL은 $30[g/m^3]$였으며 Pmax는 6.4 bar, (dP/dt)max는 100 [bar/s]가 얻어졌다. 이러한 결과로부터 LEL이 낮은 Mg는 Al보다 연소성이 큰 것으로 나타났으며, Al은 화염을 유지하는데 필요한 최저 열분해 가스농도를 확보하는데 Mg보다도 고농도의 분진이 필요함을 알 수 있었다. 또한 Mg-Al(60:40 wt%)의 LEL은 $50g/m^3$이었으며 Pmax는 9.4 bar, (dP/dt)max는 472 [bar/s]가 얻어졌다. 이러한 결과로부터 Mg-Al(60:40 wt%)합금의 연소성을 살펴보면 착화하기 쉬운 정도는 Mg와 Al의 성분비에 의해 변화하지만 Mg와 Al의 중간 정도로 나타나는 반면, Pmax는 Mg 또는 Al의 단독 물질 성분보다도 매우 큰 것을 알 수 있었다. 본 연구를 통하여 단일 성분의 Mg와 Al보다도 Mg와 Al이 일정 비율로 구성된 Mg-Al합금의 경우가 화재폭발 위험성이 증가한다는 사실을 알 수 있었으며, 이와 같은 폭발위험특성 자료를 활용하여 분진의 보관, 취급, 폐기 등의 지속적 관리가 필요하며 사업장 특성에 적합한 안전대책을 통한 사고예방대책이 요구된다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.165-174
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• 2004

In order to simultaneously vitrify the ion exchange resin(IER) and combustible dry active waste(DAW) generated from Korean nuclear power plants, a vitrification pilot test was conducted using an induction cold crucible melter(CCM) . The energy necessary for startup of the glass using a Ti-ring was evaluated as about 290 kWh. The power supplied from a high frequency generator to melt the glass properly was ranged from 160 to 190 kW without any interruption. When the mixture of the IER and DAW was fed into the CCM, the concentration of CO was lowered up to 1/40 compared to feeding the IER solely. It may be caused by the DAW which can produce about 1.8 times higher heat compared to the IER. When the swelling phenomenon occurred in the glass melt, the concentration of $NO_2$, oxidizing gas, was higher than NO, reducing gas. Total feed amounts of the IER and DAW were 368 and 751 kg, respectively. And then, about 74 of volume reduction factor was achieved.

• Journal of the Korean Geotechnical Society
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• v.34 no.6
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• pp.17-24
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• 2018

In this study, static load test and dynamic load test were performed to evaluate pile-filling material (ZA-Soil) of soil-cement injected precast pile method which was developed by using the ash of circulating fluidized boiler as a stimulant for alkali activation reaction of blast furnace slag. As a result of the static load test, the allowable bearing capacity of pile was 1,350 kN, which was the same as the result of using ordinary portland cement. And total settlement was 6.97 mm, and net settlement was 1.48 mm. These are similar to the total settlement, 7.825 mm, and net settlement, 2.005 mm of ordinary portland cement. As a result of the dynamic load test and CAPWAP analysis, the skin friction was 375.0 kN, the end bearing capacity was 3,045.9 kN, and the allowable bearing capacity was 1,368.36 kN. These results are similar to the results of using ordinary portland cement as pile-filling material.