• Economic and Environmental Geology
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• v.50 no.4
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• pp.303-311
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• 2017

The laboratory scale experiment was performed to evaluate the sealing capacity of the capping rock such as tuff and mudstone, measuring the intial supercritical $CO_2$ ($scCO_2$) injection pressure and the $scCO_2$-water-rock reaction for 90 days. The drilling cores sampled from 800 m in depth around the Janggi basin, Korea were used for the experiment. The mineralogical changes of mudstone and tuff were measured to evaluate the geochemical stability during the $scCO_2$-water-rock reaction at $CO_2$ storage condition (100 bar and $50^{\circ}C$). The rock core was fixed in the high pressurized stainless steel cell and was saturated with distilled water at 100 bar of pore water pressure. The effluent of the cell was connected to the large tank filled with 3 L of water and 2 L of $scCO_2$ at 100 bar, simulating the subsurface injection condition. The $scCO_2$ injection pressure, which was higher than 100 bar, was controlled at the influent port of the cell until the $scCO_2$ begin to penetrate into the rock and the initial injection pressure (> 100 bar) of $scCO_2$ into the rock was measured for each rock. The mineralogical compositions of mudstones after 90 days reaction were similar to those before the reaction, suggesting that the mudstone in the Janggi basin has remained relatively stable for the $scCO_2$ involved geochemical reaction. The initial $scCO_2$ injection pressure (${\Delta}P$) of a tuff in the Janggi basin was 15 bar and the continuous $scCO_2$ injection into the tuff core occurred at higher than 20 bar of injection pressure. For the mudstone in the Janggi basin, the initial $scCO_2$ injection pressure was higher than 150 bar (10 times higher than that of the tuff). From the results, the mudstone in Janggi basin was more suitable than the tuff to shield the $scCO_2$ leakage from the reservoir rock at subsurface.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.947-954
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• 1997

Selected physical properties of cornmeal extrudates fortified with dairy products and extrusion process by $CO_2$ gas injection were analysed. Dairy products including whole milk powder, whey protein concentrate non-fat dry milk, and sodium caseinate were tested at the addition of 10% and 20%, based on cornmeal weight. $CO_2$ gas was injected to the barrel at the pressure of 0.7 and 1.4 MPa. Specific mechanical energy (SME) input was decreased by the addition of dairy products. Sodium caseinate had a little effect on decreasing the SME input, however whole milk powder tremendously reduced SME input when the concentration increased. An increase in milk product content resulted in increasing the piece density at the injection pressure of 0.7 MPa. At both 10% and 20% milk product content, the piece density was lowest at the injection pressure of 0.7 MPa. The sectional expansion index was highest at the injection pressure of 0.7 MPa. However, the specific length was constantly increased with the increase in $CO_2$ injection pressure. Water absorption index was decreased and water solubility index was increased by the addition of milk products. The injection pressure of $CO_2$ was optimum at 0.7 MPa. The addition of whole milk powder limited to puff the melt, but the other milk products tested resulted in puffing with $CO_2$ injection to 1.4 MPa.

• Tunnel and Underground Space
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• v.26 no.4
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• pp.327-337
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• 2016

In this study, laboratory hydraulic fracturing tests are carried out to evaluate the effects of the cleavage anisotropy of Pocheon granite. Breakdown pressure is smaller when cracks are generated to the direction of rift plane in constant pressurization rate condition because of higher microcracks density. Besides not only injection rate changes but also the amount of injection pressure for fracture initiation and crack expansion is detected while testing due to internal deformation. Pressurization rate is higher while hydraulic fracture testing with constant injection rate condition in case of the specimen which has rift plane perpendicular to borehole because there are much flow paths to penetrate compared to the specimen which has hardway plane perpendicular to borehole. Observation by X-ray CT scanning shows that almost all of cracks due to hydraulic fracturing are generated to the direction of plane which has higher microcrack density that is rift plane or grain plane.

• Journal of Energy Engineering
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• v.26 no.3
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• pp.71-77
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• 2017

In the event of loss of coolant accident (LOCA) and station black out (SBO) in the primary system of a nuclear reactor, the coolant water should be injected to reactor coolant system (RCS) without any intervention of operators or active components. To satisfy the requirements, hybrid safety injection tank (Hybrid SIT) was suggested by Korea Atomic Energy Research Institute (KAERI). The pressure equalizing time of Hybrid SIT is an important parameter to determine the timing of coolant injection. To predict the pressure equalizing time of the Hybrid SIT, a separate effect test facility was constructed and sensitivity tests were conducted in various conditions. The main parameter determining the pressure equalizing time was obtained from separate effect test (SET) results. The wall of condensation on the inner wall of SIT and direct contact condensation on the water surface affected to the pressure equalizing time very much. In this study, the effect of each condensation phenomena on pressure equalizing time was quantitatively analyzed from results of SET and a prediction method of pressure equalizing time was proposed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.35-38
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• 2004

부틸알데히드로 오염된 대상 부지에 Biosparging 공법의 현장 적용을 위해 적정 공기 주입 압력 조건을 도출한 결과, 주 오염층인 자갈질 모래층에 공기주입 가능 파괴압력(Pe)는 약 300mmAq로 측정되었으며 4,500mmAq 압력 조건에서는 용존 산소농도의 영향 반경이 약 3 m로 나타났다. 위의 조건을 적용하여 약 150일간 운전한 결과, 영양물질을 투입하지 않은 초기 90일 동안 최고농도 대비 약 90%가 저감되었으며 그 이후에 영양물질을 투입하여 초기 최고 농도 대비 96%가 저감되어 복원목표치인 50ppm을 모든 지역에서 만족시켰다. 또한 생분해 반응속도가 k=0.03/day로 나타나 휘발성이 낮고 생분 해도가 뛰어난 부틸알데히드로 오염된 자갈질 모래층에 Biosparging공법이 성공적으로 적용된 사례이다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.399-404
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• 1996

1000MWt 급 가압경수로의 질량 및 에너지 방출량을 감소시키기 위한 방안으로 울진 3,4호기를 기준으로 안전주입계통의 형태 및 용량을 변화시키면서 원자로냉각재펌프 토출관 및 고온관 파단에 대한 질량 및 에너지 방출량 계산과 격납건물 첨두압력 및 온도의 민감도를 분석하여, 후속호기 설계에 활용하고자 한다. 분석한 여러 경우 중에서, 토출관 파단사고시 안전주입탱크 용량은 변화시키지 않고 고압안전주입펌프 용량을 l75%로 증가시키면서 저압안전주입펌프를 제거하였을 경우가 격납건물 첨두압력 및 온도가 61.98 psia (3.32 kg/$\textrm{cm}^2$A), 288.03 ℉ (142.24$^{\circ}C$)로써 가장 낮게 나타났다. 이러한 결과는 격납건물의 설계여유도를 기존보다 더 확보하므로 안전성이 향상 될 뿐만 아니라. 저압안전주입펌프를 안전주입계통에서 제외함으로써 발전소 운전에도 큰 도움이 될 것이다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.471-475
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• 2015

Because of increasing demand, a small portable drug injector that uses osmotic pressure for its operation force is developed, and its performance is evaluated. The osmotic drug injector can be small and lightweight because it does not require heavy batteries and an actuator, unlike previous electromechanical drug injectors. Moreover, its injection pressure can be sustained longer than that of previous elastic drug injectors. The new device is composed of a drug sac, osmotic pressure chamber, semipermeable membrane, and solvent chamber. To evaluate its performance, an in-vitro experiment was designed to measure the outflow and the injection pressure with respect to time. The experimental results show that the new drug infuser can continuously deliver 20 ml drug over a period of 20 h. The maximum injecting pressure was over 400 mmHg. Which prevents backflow caused by changes in the outlet pressure resulting from changes to the position of the device and the patient's posture.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.4
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• pp.286-296
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• 2016

Offshore CCS technology is to transport and inject $CO_2$ which is captured from the power plant into the saline aquifer or depleted oil-gas fields. The more accumulated injected $CO_2$, the higher reservoir pressure increases. The increment of reservoir pressure make a dramatic change of the operating conditions of transport and injection systems. Therefore, it is necessary to carefully analyze the effect of operating condition variations over the injection period in early design phase. The objective of this study is to simulate and analyze the $CO_2$ behavior in the transport and injection systems over the injection period. The storage reservoir is assumed to be gas field in the East Sea continental shelf. The whole systems were consisted of subsea pipeline, riser, topside and wellbore. Modeling and numerical analysis were carried out using OLGA 2014.1. During the 10 years injection period, the change of temperature, pressure and phase of $CO_2$ in subsea pipelines, riser, topside and wellbore were carefully analyzed. Finally, some design guidelines about compressor at inlet of subsea pipeline, heat exchanger on topside and wellhead control were proposed.

• Tunnel and Underground Space
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• v.29 no.3
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• pp.157-171
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• 2019

The fracturing by liquid carbon dioxide ($LCO_2$) as a fracking fluid has been an alternative to mitigate the environmental issues often caused by the conventional hydraulic fracking since it facilitates the fluid permeation owing to its low viscosity. This study presents how $LCO_2$ injection influences the breakdown pressure, acoustic emission, and fracture morphology. Three fracturing fluids such as $LCO_2$, water, and oil are injected with different pressurization rate to the synthetic and porous mortar specimens. Also, the shale which has been a major target formation in conventional fracking practices is also tested to examine the failure characteristics. The results show that $LCO_2$ injection induces more tortuous and undulated fractures, and particularly the larger fractures are developed in cases of shale specimen. On the other hand, the relationship between the fracturing fluids and the breakdown pressure shows opposite tendency in the tests of mortar and shale specimens.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.2
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• pp.61-66
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• 2020

Recently, a variety of electric anesthetics devices have been developed and used in clinical practice to reduce the fatigue of the operator during local anesthesia for dental procedures and to compensate for the disadvantages of manual anesthesia device. In this electric anesthesia injection device, the accurate and constant delivery of pressure for drug infusion is a very important performance factor. In order to evaluate the accuracy of the transfer pressure, a small pressure gauge using a load cell is often used, but since the elastic body inside the load cell may not be able to accommodate a sufficient displacement, an error may occur when evaluating pressure performance. For these reasons, in this study, we proposed and evaluated a silicon-chrome steel (Si-Cr steel) spring jig that can accommodate relatively large displacements that can be used when evaluating the performance of a pressure-controlled pressure application device using a load cell type pressure gauge. As a result of the pressure transmissibility test and repeated measurement results using a commercial dental anesthesia injection device, a more stable result was obtained when using a spring jig, and it was confirmed that the frequency of abnormally high measurement was reduced.