• Structural Engineering and Mechanics
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• 제84권3호
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• pp.337-344
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• 2022

Due to corrosion defects on the surface of the oil pipe, the sealing performance of the annular blowout preventer (BOP) decreases, and the leakage of toxic and harmful gases such as H₂S and SO₂ will threaten the safety of operators on the well. Therefore, this paper establishes the FE model for evaluating the sealing performance of BOP-oil pipe corrosion defects, which is based on the rubber large deformation theory and rubber core sealing mechanism, and designs the experiment of BOP sealing performance to verify the accuracy of the FE model. The sealing performance of BOP sealing oil pipe with corrosion defects is studied. The research results show that the sealing performance of BOP is more sensitive to the axial size of corrosion defects. With the increase of oil pipe outer diameter, the critical size of defects increases continuously. The sensitivity of radial and depth dimensions is low, When for 88.9 mm outer diameter oil pipe, the axial critical size of corrosion defect is 20 mm, the radial critical size is 16 mm and the critical depth is 2 mm. Fit the formula between the outer diameter of oil pipe and the piston increment. According to the formula, the operator can calculate the piston stroke increment required by the BOP to complete the sealing when the oil pipe is corroded.

• 한국응급구조학회지
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• 제22권1호
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• pp.73-82
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• 2018

Purpose: The purpose of this study was to compare the tidal volumes and airway pressures of 3 mask-sealing methods (one hand C-E, two hands C-E, and one hand O-E) for ventilation treatment. Methods: The study subjects were 45 paramedic students. Tidal volume was measured for the three sealing methods by setting a ventilator, connecting it to the masks for 2 minutes, and using Respi-trainer software. Results: Regarding general characteristics, the group of men, in upper grades, and with practical training experience and experience and experience in the implementation of bag-valve-mask ventilation provided higher tidal volumes. Regarding physical characteristics, larger hands and greater grip strength correlated with higher tidal volume. Two hands C-E generated the highest tidal volume of $483.78{\pm}34.14mL$, one hand O-E generated $449.59{\pm}51.09mL$ and one hand C-E generated $394.31{\pm}68.95mL$. Conclusion: Means of tidal volumes were statistically significantly different based on mask sealing methods (p<.001). Two hand C-E was performed by the two-persons task and was suggested as the most effective method. For the one-person task, one hand O-E was the more effective method compared to the previous one hand C-E.

• Advances in aircraft and spacecraft science
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• 제5권3호
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• pp.319-334
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• 2018

In this study, the failure mode and energy absorption capabilities of a composite shock absorber device, during an emergency landing are evaluated. The prototype has been installed and tested in laboratory simulating an emergency landing test condition. The crash absorber presents an innovative configuration able to reduce the loads transmitted to a helicopter fuselage during an emergency landing. It consists of a composite tailored tube installed on the landing gear strut. During an emergency landing this crash absorber system should be able to absorb energy through a pre-designed deformation. This solution, compared to an oleo-pneumatic shock absorber, avoids sealing checks, very high values of the shock absorber pressure, and results to be lighter, easy in maintenance, inspect and use. The activities reported in this paper have become an attractive research field both from the scientific viewpoint and the prospect of industrial applications, because they offer benefits in terms of energy absorbing, weight savings, increasing the safety levels, and finally reducing the costs in a global sense.

• 한국응급구조학회지
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• 제21권3호
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• pp.7-16
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• 2017

Purpose: The purpose of the study was to investigate the effects of laryngeal mask airway (LMA) insertion from different positions, using different methods, on the quality of the insertion, for identifying a more convenient and effective insertion method. Methods: In a model ambulance, 30 paramedic students performed the LMA insertion procedure, in four different settings, combinations of the rescuer's position (at the head end of the patient, at the side of the patient), and insertion technique (index finger insertion, thumb insertion), in a randomized order. Quality of insertion index and convenience of use were measured. Results: The quality of insertion index (tidal volume, gastric insufflation, airway pressure, airway sealing pressure, midline positions, insertion success grade, and insertion time) were not significantly different among four different settings. However LMA insertion from the anterior (head) end, using the index finger method compared to the thumb method was found to be significantly more convenient. Conclusion: We recommend using the more convenient and familiar LMA insertion method, between index finger insertion and thumb insertion, regardless of rescuer's position.

• 한국응급구조학회지
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• 제26권3호
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• pp.37-46
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• 2022

Purpose: TThe experiment was designed to compare the efficiency of ventilation between conventional BVM ventilation and a newly devised A-BVM ventilation method with Tidal volume, total ventilation rate, average Ventilation speed, and average Ventilation volume. Methods: 40 Paramedical students who agreed to participate in the study were analyzed. Values were measured using IMB PASS after 2 minutes of Brayden Pro manikin with BVM and A-BVM ventilation. The difference in general characteristics was assessed by t-test and ANOVA and the difference in ventilation methods was analyzed by IBM SPSS. Results: A significant difference was found between the two ventilation methods in terms of tidal volume (t=-11.203, p<.001), ventilation time (t=-3.834, p<.001), and optimum ventilation probability (t=10.770, p<.001). A-BVM ventilation method, rather than BVM ventilation method, showed a value close to the appropriate amount recommended by Korean Advanced Life Support (500~600mL) in tidal volume, and higher in optimum ventilation probability. Conclusion: We could identify the a better mode of ventilation. Further studies on the efficacy of existing BVM ventilation methods as compared to device augmented BVM ventilation methods should be carried out to ensure that adequate ventilation is available to patients in clinical practice.

• 한국해양공학회지
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• 제25권2호
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• pp.127-133
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• 2011

The following Technology Report was written with respect to recent offshore technology development. This report was prepared with the purpose of suggesting recent offshore technology and upcoming visions by describing the principles of an offshore drilling operation, the NL Tensioner Cylinder Package R & D, and the general technology related to three offshore patent areas, as major contents.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3919-3927
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• 2022

This study presents an optimal design of the coolant system of a non-refueling full-life small reactor by analyzing the space-integrated geometrical and electromagnetic variables of an extra vessel electromagnetic pump (EVEMP) for the circulation of a lead-bismuth eutectic (LBE) coolant. The EVEMP is an ideal alternative to the thermal-hydraulic system of non-refueling full-life micro reactors as it possesses no internal structures, such as impellors or sealing structures, for the transportation of LBE. Typically, the LBE passes through the annular flow channel of a reactor, is cooled by the heat exchanger, and then circulates back to the EVEMP flow channel. This thermal-hydraulic flow method is similar to natural circulation, which enhances thermal efficiency, while providing a golden time for cooling cores in the event of an emergency. When the forced circulation technology of the EVEMP was applied, the non-refueling full-life micro reactor achieve an output power of 60 MWt, which is higher than that achievable via the natural circulation method (30 MWt). Accordingly, an optimized EVEMP for Micro URANUS with a flow rate of 4196 kg/s and developed pressure of 73 kPa under a working temperature of 250 ℃ was designed.

• 한국재난정보학회 논문집
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• 제19권3호
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• pp.582-596
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• 2023

연구목적: 본 연구는 원전사고 발생 시 임시 대피시설의 안전성을 강화할 수 있는 방안을 연구하였다. 연구방법: 본 연구에서는 과거의 체르노빌, 후쿠시마, 쓰리마일섬(TMI) 원전사고에 대한 사례연구를 활용하였다. 연구결과: 현재의 방사선 비상 대응 계획은 소개에 중점을 두고 있으며, 실내대피 개념은 단순히 주민 대피를 지원하는 수단으로 활용되고 있다. 그러나 사례연구를 통해 INES-5 이상의 사고의 경우, 소개보다 실내대피를 장려하는 것이 사상자 최소화에 효과적임을 확인하였다. 더 나은 실내대피를 보장하기 위해 아파트를 임시 대피소로 활용할 것을 권장하며, 아파트가 방사선 방호 기술을 갖추도록 개선사항을 제안한다. 결론: 더 나은 실내대피를 보장하기 위해 아파트를 임시 대피소로 활용할 것을 권장하며, 차폐, 양압, 밀폐기술을 이용해서 아파트의 성능을 보완하고자 한다.

• 한국화재소방학회논문지
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• 제34권1호
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• pp.135-141
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• 2020

2015년 바레인에서 귀국한 한국인이 처음으로 메르스 확진 판정을 받으면서 대한민국 메르스 유입이 확인되었다. 최초 메르스 확진 판정 후 감염자가 병원으로 후송 된 후 2차 감염자가 늘어났고 그 이후 대한민국은 메르스 공포에 떨어야 했다. 이 때 격리구급차 도입이 이루어지고 있었으나 들것 이송 중 오염에 대해서는 뾰족한 방법이 없었고 격리구급차 도입이 제한적으로만 이루어지고 있었기에 서울대학교 병원과 서울시립대학교에서는 이송용 격리 이송 장치 및 공기정화장치(양·음압기)를 개발하였다. 하지만 메르스 사태가 발생한지 4년이 지난 현재까지도 격리이송장치 및 공기정화장치에 대한 성능평가 시험법이 미흡한바 본 연구에서는 시뮬레이션 및 시험을 통하여 도출된 차압, 공기의 흐름에 따른 결과를 통하여 소형격리장비 내부와 외부의 차압을 측정하여 바이러스의 외부유출 및 내부밀폐가 가능한 최소 수치를 제안 하였으며, 이를 통하여 소형격리이송장비의 성능평가 및 시험법에 대하여 제안하였다. 해당 소형격리이송장비의 중요 기능을 정의하고 이를 평가항목으로 선정하여 현실과 유사한 상황을 모사하여 성능평가를 수행하였다. 그 결과 격리이송장치 내부의 양압과 음압의 적절한 압력 구성과 헤파필터의 명확한 기준이 명시되어 격리이송장치 및 공기정화장치의 성능기준을 명확하게 규정해야 함을 도출하였다.