• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.164-167
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• 2003

In generally, Gas fill & drain valve is used in filling Gases to tank on high pressure in launcher The valve is quick coupling type and is separated by manual or remote control. In KSR-III, He gas fill & drain valve separated by remote control is used. In this paper, that are explained about the design specification, the test procedure, the autonomous test result and the flight test result.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.338-341
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• 2006

본 연구에서는 지하수내 TCE 농도가 높은 2개 지역을 선정하여 3회에 걸쳐 공기탈기법 시험을 실시하였다. 2개 지역의 지하수내 TCE 배경 농도는 각각 0.360, 0.317 mg/L이며 반응조에 주입된 공기는 각각 17.14, 44.78, 76.51 L/min의 비율로 주입하였다. 또한 반응조에서 배출되는 기체내의 TCE의 농도를 측정하기위해 PID(photo-ionization detector)를 장착하여 측정하였다. PID를 이용하여 배출되는 기체를 측정한 결과, TCE 농도는 $6{\sim}8$분만에 최고 농도로 배출되었고 시간이 지날수록 천천히 감소하는 형태를 나타내었다. 반응조내의 TCE 농도 변화는 공기 유입 속도에 따라 매우 큰 변화를 나타내었다. TCE가 17.14 L/min의 공기유입속도에서 160분 동안 64%, 44.78 L/min에서 135분 동안 93%, 76.51 L/min에서 120분 동안 95.3%가 제거되었다. 따라서 TCE를 제거하기 위한 DAS 기법은 공기의 주입비율에 따라 제거 속도의 큰 변화를 보였다.

• The Journal of Engineering Geology
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• v.28 no.1
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• pp.81-99
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• 2018

Excessive groundwater discharge by tunneling and tunnel operation can lead to groundwater exhaustion and ground subsidence. Therefore, it is very important to evaluate environmental impact and to establish mitigation measures of the impact related to tunnel excavation based on hydrogeological and modeling approaches. This study examined the depletion of surface reservoirs and valley water due to tunnel excavation through field survey, water quality analysis, tracer test, and groundwater modeling. As a result of field water quality test, the concentration of chemical constituents in groundwater discharge into the tunnel is slightly higher than that of valley water. By the result of laboratory water analysis, both valley water and the groundwater belong to $Ca^{2+}+HCO_3{^-}$ type. Tracer test that was conducted between the valley at the injection point and the tunnel, indicates valley water infiltration into the ground and flowing out to the tunnel, with maximum electrical conductance changes of $70{\mu}S/cm$ in the first test and of $40{\mu}S/cm$ in the second test. By groundwater modeling, the groundwater discharge rate into the tunnel during tunnel construction is estimated as $4,942m^3/day$ and groundwater level recovers in 3 years from the tunnel completion. As a result of particle tracking modeling, the nearest particle reaches the tunnel after 6 hours and the farthest particle reaches the tunnel after 9 hours, similarly to the case of the field trace test.

• Journal of the Korean GEO-environmental Society
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• v.9 no.2
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• pp.31-37
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• 2008

Diffused Aeration System (DAS) is one of the remediation methods used for removing contaminants in groundwater and this method brings air bubbles in contact with contaminated water, afterwards transferring contaminants in liquid phase into air phase. In this study, three applicability tests using DAS were conducted in two highly contaminated sites. For these tests, diffused air bubbles are generated with a in-flow rate of 17.1, 44.8 and 76.5 (1/min), respectively. The concentrations of TCE in grounwater and air phase were measured during the tests. The measured results showed that TCE concentration hit the highest value after 6~8 min and afterwards decreased gradually. Also, it was observed that the TCE concentration in air phase changed depending on the rate of diffused aeration. In addition, $K_La$ values from liquid to air phase were calculated based on the test results and those of three tests (test 1, 2 3) were 0.444, 1.158 and 1.836(1/hr), respectively. From the comparison of $K_La$ values, the faster air in-flow rate is, the higher the efficiency of the DAS is.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.115-127
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• 2019

The low-flow grouting injection technique, the target construction method for this study, is a method of pouring mortar into the ground by non-emission replacement principle, which can be expected to increase the density of the ground, and, in some cases, be used as a base file using the strength of the high injection solids, along with low noise, low pollution, and high durability. To verify that the dynamic characteristics of the ground are improved by the low-flow injection technique, the test work was conducted on the site and physical tests were performed, and the quality of the improvement formed in the ground was verified through the indoor test on the core and core recovery rate was analyzed. The density logs test layer calculated the volume density of the ground layer by using the Compton scattering of gamma-rays, and the sonic logs was tested on the ground around the drill hole using a detector consisting of sonar and receiver devices inside the drill hole. As a result of the measurement of the change in physical properties (density and sonic logs) before and after grouting, both properties were basically increased after infusion of grout agent. However, the variation in density increase was greater than the increase in speed after grouting, and the ground density measurement method was thought to be effective in measuring the fill effect of the filler. Strength and core recovery rates were measured from specimens taken after the age of 28 days, and the results of the test results of the diffusion and strength test of the improved products were verified to satisfy the design criteria, thereby satisfying the seismic performance reinforcement.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.225-231
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• 2001

This study was conducted to find out the optimal aeration rates for minimizing odor emission and for increasing biological activities during composting of livestock manure in the enclosed bench-scale reactor system. It was treated with the mixture of poultry manure and sawdust controlled the initial water content of 60%, then aerated continuously at four different aeration rates (0.1, 0.2, 0.4 and 0.6 L/min/kg dry-solids). The average emitted concentration of ammonia in 0.6 L/min/kg dry-solids during composting reached the level of 40% in comparison with that of 0.2 L/min/kg dry-solids. In cases of sulfur compounds such as hydrogen sulfide, methylmercaptan and ethylmercaptan, their concentrations decreased with increasing aeration rates and the emission time was shortened. But they didn't detect in the treatment of 0.6 L/min/kg dry-solids. The biological activity for composting showed a trend of increasing as aeration rates increased. The treatment of 0.6 L/min/kg dry-solids gave the highest biological activity and the best compost quality.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.539-539
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• 2012

전북대학교 고온플라즈마 응용연구센터는 교육과학기술부 기초연구사업 중 고가연구장비 구축사업의 일환으로, 고 엔탈피, 초음속 유동 환경을 모사하여, 항공우주, 군사기기, 핵융합 분야 등의 고온 재료 개발을 위한 기초 연구 장치로써, 0.4MW급 플라즈마 풍동 장치를 구축하고 있다. 0.4MW 플라즈마 풍동 장치의 플라즈마 발생부는 DC 전원 공급장치와 디스크 형태의 양극과 음극 사이에 동일 형태의 간극을 삽입한 0.4MW급 분절형 아크 플라즈마 토치로 구성되었으며, 토치에서 발생된 아크 플라즈마는 노즐을 통과하며 마하 2~4의 초음속을 나타내도록 설계 제작되었다. 시험 챔버는 노즐에서 나온 초음속 플라즈마의 특성 및 재료 시험을 위한 3차원 이송식 기판이 장착되어 있으며, 고 엔탈피 유동을 관측하기 위한 광학창을 구비하였다. 시험 챔버 하류에는 유동 안정을 위한 디퓨저(diffuser)가 설치되어 있으며, 디퓨저(diffuser)로부터 배출되는 고온가스는 열교환기를 통해 냉각된 후 진공펌프를 통해 대기로 배출되게 된다. 장치의 압력조절을 위하여 $1,000m^3/min$의 용량의 진공펌프 시스템이 설치될 예정이며 가스공급장치, 냉각수 공급장치, 디퓨져, 열교환기는 1MW급 용량으로 설계 제작되었다. 본 장치는 400kW의 전원 공급, 15 g/s의 공기유량 주입 시 약 13 MJ/kg의 고엔탈피를 가진, mach 2~4의 초음속 유동을 나타내는 것을 특징으로 한다.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.279-289
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• 2013

The most critical factor in developing coalbed methane(CBM) reservoir is absolute permeability. Both productivity and economics of the CBM depend on the absolute permeability. The methods to estimate it are core analysis and well test. However, absolute permeability determined by core analysis cannot be a good representative of CBM reservoir. Therefore, it is generally estimated by well test. In this study, well test methods applicable of CBM reservoir were classified with their characteristics. Merits and demerits of each well tests were also analyzed. Based on those parameters, design considerations and procedures of well test were derived. After each well tests was performed, the procedure of well test interpretations to estimate reservoir properties such as absolute permeability and skin factor was presented.

• Economic and Environmental Geology
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• v.49 no.6
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• pp.445-458
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• 2016

Most of water curtain cultivation (WCC) area in Korea has been inveterately suffering from the gradual draw-down of groundwater level and related shortage of water resources at the late stage of WCC peak time. To solve this problem, artificial recharge techniques has been recently applied to some WCC area. This study introduces infiltration gallery, which is one of the artificial recharge methods, and tentatively examined the effectiveness of three galleries installed at Sangdae-ri WCC area of Cheongju City. Seven galleries are set up at each empty space between eight vinyl houses in this area and its dimension is designed as 50 cm in each width and height and 300 cm in each length. Installation process was including bed excavation, backfill with gravels and silica sands, and completion of gallery by equipment of piezometer and covering with non-woven cloth. For each B, C, D gallery, 3 types of test including preliminary, four step and one long-term injection were performed. The first preliminary test showed the rough relations between injection rates and water level rise as follows; 20 cm and 30 cm level rise for $33.29{\sim}33.84m^3/d$ and $45.60{\sim}46.99m^3/d$ in B gallery; 0 cm, 16 cm and 33 cm level rise for $21.1m^3/d$, $33.98m^3/d$ and $41.69m^3/d$ in C gallery; 29 cm and 42 cm level rise for $48.10m^3/d$ and $52.23m^3/d$ in D gallery. Afterwards, more quantitative results estimating effectiveness of artificial recharge were reasoned out through stepped and long-term injection tests, which is expected to be employed for estimating water quantity re-injected into the aquifer through these galleries by natural injection over the period of WCC peak time.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.207-215
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• 2018

Almost all countries of the world have recently made great efforts to reduce green-house gases to alleviate the global warming threatening human survival, because a huge amount of carbon dioxide as one of the main green-house gases has been emitted from the combustion processes of fossil fuels such as coal and oil. $CO_2$ capture and storage (CCS) technology is a representative method to diminish the green-house gases, and actively investigated by many countries. This study focuses on the design and construction of a high pressure $CO_2$ injection facility to store it to underground, which is the first $CO_2$ injection in Korea following the steps of the $CO_2$ capture from large $CO_2$ emission sources and transportation to the sea. Injection tests of $CO_2$ on the platform on the sea were carried out in Yeongil Bay of Pohang city in the early 2017. Thus, we were able to perceive the necessary operating conditions of the injection facility, injection characteristic, and knowhow of the injection facility. The results obtained from the injection test shall be utilized for facility upgrades and scale-ups.