• Journal of the Korean Institute of Gas
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• v.19 no.3
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• pp.32-37
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• 2015

The boil-off-gases(BOG) in cryogenic LNG storage tanks are generating continuously due to the heat leakage and need to be re-liquefied by the effective way. As the present method to reliquefy BOG is using LNG cold energy to be supplied after low pressure primary pump, the demand of LNG flow rate should be over 10 times of BOG produced rate to reliquefy it. This research invented new effective re-liquefaction system having only 3~4 times of LNG flow rate against unit BOG, that the pre-liquefaction process of NGL and the use of high pressure LNG cold energy after secondary pump. By the analysis, it could be high efficient reliquefying system for all amount of BOG treatment even during the summer time, and improvement of operation safety and efficiency of LNG terminal.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.391-392
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• 2003

한전 원자력 환경기술원에서는 중ㆍ저준위 방사성폐기물 유리화 기술의 상용화 가능성을 입증하기 위한 유리화 실증설비를 건설하여 시험 중에 있으며 이 유리화 기술은 유도 가열식 저온로(Cold Crucible Melter, CCM)에 폐기물을 투입하는 기술로서 폐기물의 부피 축소 효과와 더불어 최종 고화물로 생성되는 폐기물의 침출율이 매우 낮은 장점을 지닌다. 이와 같은 유리화 공정은 기존의 소각처리에서와 같이 폐기물의 열적 산화과정에 의해 유해오염가스와 입자성 물질이 발생된다. 따라서 이를 처리하기 위해배기체 처리공정(Off Gas Treatment System, OGTS)을 설치하여 환경 배출기준(SO$_2$300ppm, NO$_2$ 200ppm, CO 600ppm, HCI 50ppm, 분진 100mg/Nm$^3$ 등)을 만족하도록 하였고 특히 입자성 물질은 후단 OGTS나 배관내 침적으로 인한 방사성 오염을 막기 위해 CCM 후단에서 효율적으로 제거되어야만 한다. (중략)

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.3
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• pp.221-227
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• 2010

The solidification methods for powder wastes dried at CWDS(Concentrate Waste Drying System) in PWR have been studied in a variety of ways both at home and abroad. The solidification for these wastes has been performed using stabilization agents such as cement, paraffin and polymer. The applicability studies to maximize the reduction ratio of wastes and operational effectiveness for wastes treatment have been carried out, recently. It is necessary to pretreat the powder wastes before feeding wastes to vitrification facility because the fines flying brings about clogging of feeding pipes and off-gas treatment system or workers' exposure to radiation during maintenance. This paper describes an effective method for treatment of powder wastes to improve safety and stability of vitrification facilities.

• Korean Journal of Environmental Agriculture
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• v.27 no.3
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• pp.279-284
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• 2008

We investigated whether carboxylate exudation of Brassica pekinensis Rupr. was affected by nitrate deposition from simulated acid rain. A gas chromatographic (GC) analysis was employed for the determination of low molecular weight organic acids (LOA) in rhizosphere soils, bulk soil, roots and leaves of Brassica pekinensis Rupr.. Rhizosphere soils were collected after 8 weeks of plant growth by first removing the bulk soil from the root system and then by mechanical move off the rhizosphere soil that adhered to the root surface with soft brush. Soil and plant materials were simultaneously extracted with the mixture of methanol and sulfuric acid (100:7, v/v). Seven organic acids, oxalic, malonic, fumaric, succinic, maleic, L-malic and citric acid were identified and quantified by GC equipped with FID. Oxalic, L-malic, and citric acids were found in both the bulk and rhizosphere soils, while most LOAs were not detected in the control treatment. On the contrary, except maleic acid, all other organic acids were detected in the leaves and roots of cabbages treated with nitrate deposition.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.347-350
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• 2002

The petrochemical products can cause soil and groundwater contamination during their transportation and the use of the products, and while being contained in underground storage tanks(USTs) throughout the leakage. To treat the contaminated soil, the bioventing method is suitable for the remediation of semi-volatile compounds, such as diesel and kerosene. Biofiltration is one of possible method to treat the off-gas produced in the process of the bioventing. This study is related to the usage, effectiveness of treatment, and feasibility of two types of biofilter system made of ceramic-compost and polymer respectively to treat diesel VOCs at constant retention time of 20 sec. Compost biofilter showed the average removal efficiency of 73 % when the inlet concentration increased to 20 ppmv. Increased the inlet concentration decreased the microbial activities as well as the removal efficiency. On the contrary, the removal efficiency of the polyurethane biofilter was maintained at 88 % at the inlet concentration of 13 ppmv during ten days and was obtained to 80 % at the inlet concentration of 30 ppmv in spite of the drop of the efficiency in the sudden increase of the inlet concentration. At the beginning of the experiment it showed low removal efficiency at low inlet concentration due to the low microbial activity, however, as experiments proceed the removal efficiency could be obtained more than 80% at high inlet concentration.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.1027-1031
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• 2006

Recently, mobile-type analysis system when emergency patient can check his blood condition in the transportation or vessel has being required. Under the present system, it takes lots off-time to know the blood analysis result of patient, so, it may lead to a dangerous situation. But, in this study, analysis time makes to fall down to $1{\sim}min$. to emergency treatment patient more quickly, and you can check the information by wireless PC through Bluetooth base. It is able to measure in about 7minutes from 25minutes of warming-up time in existing facilities by testing temperature peculiarity curve, to operate system without error even minute temperature change by adoption DUAL heating. And Bluetooth base was adopted to reduce power consumption and be able to hospital networking by keeping and sending analyzed data when it needs.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.1
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• pp.61-66
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• 2006

The combined ADEPT(Anaerobic Digestion Elutriated Phased Treatment)-SHARON(Single reactor system for High Ammonium Removal Over nitrite)-ANAMMOX(Anaerobic ammonium oxidation) processes were operated for resources recovery and nitrogen removal from slurry-type piggery waste. The ADEPT process operated at an acidogenic loading rates of 3.95 gSCOD/L-day, the SCOD elutriation rate and acid production rate were 5.3 gSCOD/L-day and 3.3 gVFAs(as COD)/L-day, respectively. VS reduction and SCOD reduction by the hydrolysis were 13% and 0.19 $gSCOD_{prod.}/gVS_{feeding}$, respcetively. Also, the acid production rate was 0.80 $gVFAs/gSCOD_{prod}$. In methanogenic reactor, the gas production rate and methane content were 2.8 L/day($0.3m^3CH_4/kgCOD_{removal}@STP$) and 77%, respectively. With these operating condition, the removals of nitrogen and phosphorus were 94.1% as $NH_4-N$(86.5% as TKN) and 87.3% as T-P respectively.

• Membrane Journal
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• v.27 no.4
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• pp.367-373
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• 2017

Pressurized membrane module systems, including hollow fiber type of Microfiltration (MF) and Ultrafiltration (UF) membranes are being increasingly used in drinking water treatment due to their high removal efficiency of pathogen. However, when fibers are damaged in pressurized membrane system, the pathogen will be able to penetrate the membrane. Therefore, it is essential to guarantee the regulatory requirements for water quality by an effective on-line or off-line condition integrity monitoring methods. Recently, pressure decay test (PDT) which is one of membrane integrity tests has been reflected to drinking water treatment plants using pressurized membrane module. In this paper, three different method were used to perform PDT and three different sensitivity values were analyzed through experiments. Three types of direct integrity test methods were applied to pressure feed side, filtrate side and bidirectional pressure decay test. The results of these experiments show that the sensitivity was increasing when the volume of pressurized gas was decreasing. The sensitivity is inversely proportional to the gas volume. Furthermore, it is desirable to increase pressure difference between feed side and permeate side in order to achieve higher sensitivity in the PDT by membrane damage.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.65-73
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• 2008

Because main barley straw management is changing these days from off-fields to burning that may relate to air quality concerning the global warming, this study was conducted to investigate the effects of barley-straw management practices on greenhouse gas emissions during rice cultivation in rice-barley double cropping system. The treatments were barley straw burning, off-field usage of barley straw and incorporation of barley straw in paddy fields. Laboratory experiment showed that burning of barley straw at the rate of $4.5Mg\;ha^{-1}$ emitted GHGs in the amounts of 4,607, 19.5, and $0.9kg\;ha^{-1}$ of $CO_2$, $CH_4$, and $N_2O$, respectively. During the rice cultivation of the rice-barley double cropping system, the highest GHG emission by evaluated close-static chamber method was observed from the soil incorporation of barley straw with 387 and $1.0kg\;ha^{-1}$ of $CH_4$ and $N_2O$, respectively. The GHGs emissions from the barley straw burning and off-field usage treatments were 233 and $160kg\;ha^{-1}$ for $CH_4$ and 0.80 and $0.79kg\;ha^{-1}$ for $N_2O$, respectively. The barley straw burning treatment showed the greatest GHGs emission among barley straw management practices in rice-barley double cropping system when considering GHGs emissions both during burning and from paddy fields during the cropping seasons. As a result, the GHGs emissions recorded in the barley straw incorporation to soil and off-field usage treatments were 22.4 and 66.8%, respectively, less than sum of GHGs emissions from the burning of barley straw and from paddy fields during rice cultivation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1370-1374
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• 2018

A heterojunction $SnS_2/p-Si$ photodetector was fabricated by RF magnetron sputtering system. $SnS_2$ was formed with 2-inch $SnS_2$ target. Al was applied as the front and the back metal contacts. Rapid thermal process was conducted at $500^{\circ}C$ to enhance the contact quality. 2D material such as $SnS_2$, MoS2 is very attractive in various fields such as field effect transistors (FET), photovoltaic fields such as photovoltaic devices, optical sensors and gas sensors. 2D material can play a significant role in the development of high performance sensors, especially due to the advantages of large surface area, nanoscale thickness and easy surface treatment. Especially, $SnS_2$ has a indirect bandgap in the single and bulk states and its value is 2 eV-2.6 eV which is considerably larger than that of the other 2D material. The large bandgap of $SnS_2$ offers the advantage for the large on-off current ratio and low leakage current. The $SnS_2/p-Si$ photodetector clearly shows the current rectification when the thickness of $SnS_2$ is 80 nm compared to when it is 135 nm. The highest photocurrent is $19.73{\mu}A$ at the wavelength of 740 nm with $SnS_2$ thickness of 80 nm. The combination of 2D materials with Si may enhance the Si photoelectric device performance with controlling the thickness of 2D layer.