• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.53-59
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• 2022

Static seals are used to seal high temperature gas and cryogenic fluid under high pressure, at interfaces between liquid rocket engine components such as combustion chamber, turbopump, gas generator, valves, etc. As thermal expansion and contraction at assembly interfaces cause undesirable leakage under cryogenic and high temperature environments, static seals applied for sealing of joint interfaces without relative motion should be designed properly. The additional function of rotation at the sealing face is also required for static seals, when the spherical flange is used for improvement of assembly at misalignment interfaces. In this study, structural analysis and leak tightness test of simulating test rig for several important interfaces are performed, to verify structural integrity of static seals.

• Journal of the Korean Society of Safety
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• v.38 no.3
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• pp.43-50
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• 2023

Silicone tetrachloride (SiCl₄) leak accidents cause enormous human and environmental damage because it is highly toxic. Some handling facilities use water curtains to reduce the impact range of SiCl₄. Although the water curtain is known as one of the most efficient technologies for post-release mitigation, its effect on reducing SiCl₄ concentration needs to be investigated scientifically and quantitatively. In this study, three-dimensional computational fluid dynamics (CFD) was used to investigate the physical and chemical effects of water curtains as a release-mitigation system for SiCl₄. SiCl₄ is released and dispersed five seconds prior to the operation of the water curtain. Once the water curtain works, the SiCl₄ reacts chemically with the water and its concentration decreases rapidly; it reaches an emergency response planning guidelines level 2 (ERPG-2) of 5 parts per million (ppm) at about 570 m. We observed, however, that the physical effect of water curtains on reducing SiCl₄ concentration is insignificant when the chemical effect is eliminated. These results are crucial since they can be a scientific and quantitative basis for the 'technical guidelines for estimating the accident affected range'. In order to protect the public from chemical accidents, more toxic gas mitigation technologies need to be developed.

• Journal of the Korean Institute of Gas
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• v.27 no.2
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• pp.32-38
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• 2023

In a chemical plant, while supplying corrosive fluid to a storage tank with a pump, an accident occurred where the corrosive fluid leaked through the upper exhaust vent because the level indicator was not accurately determined. There are various causes of leakage accidents, but we focused on the sticking of the level indicator of the level gauge, which is the direct cause. As a result of the analysis, the level indicator used in the workplace where the accident occurred was randomly replaced, and in the summer when the accident occurred, the tubular type level gauge was found to be more likely to stick than other types because thermal expansion easily occurs. In addition, there were difficulties in reviewing the proper installation because the installation standards for measuring instruments installed in storage tanks were not clear in Korea. Therefore, in this study, based on accident cases and overseas standards, we are going to find out about precautions when installing storage tank instrumentation.

• Journal of Wetlands Research
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• v.17 no.1
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• pp.45-52
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• 2015

We obtained the following results from investigation on vegetation damage from 5 to 6 August, 2013, about one year after an accident that hydrofluoric acid leaked from a chemical maker, Hube Globe in Gumi. Pinus densiflora and Pinus strobus showed very severe damage. Ginko biloba, Quercus acutissima, Pinus rigida, Salix glandulosa, Hibiscus syriacus, and Lagerstroemia indica showed severe damage. Quercus variabilis, Lespedeza cyrtobotrya, and Miscanthus sinensis showed moderate damage. Quercus aliena, Smilax china, Arundidinella hirta, Ailanthus altissima, Robinia pseudoacacia, and Paulowinia coreana showed slight damage. We did not find any plants without leaf damage around there. This result means that fluoride damage still persists in this area as was known that fluoride remains for a long time in air, soil and water and exerts negative effects at all levels of an ecosystem. In addition, fluoride content contained in plant leaf depended on the distance from a fertilizer producing factory and vegetation damage tended to proportionate to the concentration in the Yeocheon industrial complex. In these respects, a measure for removal or detoxification of the remaining fluoride is urgently required around the hydrofluoric acid leak spot. Fertilizing of dolomite containing Ca and Mg, which can trap fluoride, was prepared as one of the restoration plans. In addition, phosphate fertilizing was added in order to enhance soil ameliorating effects. Furthermore, we recommend the introduction of tolerant plants as the second measure to mitigate fluoride damage. As the tolerant plants to make a new forest by replacing trees died due to hydrofluoric acid gas damage, we recommended Q. aliena and S. china, A. hirta, etc. were recommended as plant species to add mantle vegetation to the forest margin to ensure stable interior environment of the forest.

• Journal of Advanced Research in Ocean Engineering
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• v.3 no.1
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• pp.1-14
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• 2017

The safety analysis of an earthquake is carried out during the operation of a subsea pipeline and an onshore pipeline. Several cases are proposed for consideration. In the case of a buried pipeline, permanent ground deformation by the earthquake and an increase of internal pressure by the acceleration of the earthquake should be considered. In the case of a subsea pipeline, a bending moment is caused by liquefaction of the backfill material on a trenched seabed, etc., which results in a high bending moment of the buried pipeline. The bending moment causes the collapse of the subsea pipeline or a leak of crude oil or gas, which results in economic loss due to enormous environmental contamination and social economic loss owing to operation functional failure. Thus, in order to prevent economic loss and operation loss, structurally sensitive design with regard to seismic characteristics must be performed in the buried pipeline in advance, and the negative impact on the buried pipeline must be minimized by conducting a thorough analysis on the seabed and backfilling material selection. Moreover, it is proposed to consider the selection of material properties for the buried pipeline. A more economical review is also required for detailed study.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.115-121
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• 2000

As the development of industry water quality of river is going to bad because of waste water of an industrial complex and general home agricultural chemicals exhaust of $SO_3$ and CO gas acid rain and so on. Corrosion damage of boiler factory equipment and so forth occur quickly due to using of the polluted water resulting in increasing leak accident. Especially working life of hot water boiler using the polluted water becomes more short and energy loss increases. The cathodic protection method is the most economical and reliable one to prevent corrosion damage of steel structures. Mg-base alloys galvanic anode protection of cathodic protection method is suitable for than application of hot water boiler using water with high specific resistance such as tap water. This paper is studied on the cathodic protection characteristics of how water boiler. In tap water and 0.001mol/$\ell$ NaCl solution the characteristics of anodic polarization of Mg-base alloys galvanic anode and tube material is investigated the measurement of cathodic protection potential according to the time elaspsed is carried out.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.3
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• pp.39-46
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• 2011

The automotive air conditioning hose is used for connecting the components of air conditioner in a vehicle. The hose is usually manufactured by the swaging process to connect the rubber hose with the metal fitting at the end of the hose. In case that the clamping force is small, the refrigerant gas in the hose can leak locally under the severe operating circumstances. The practical test of clamping force is performed by means of the measurement of separation force. In this study, the swaging process of a hose is simulated with the finite element method, to investigate the effect of friction coefficient on the clamping force. The contact condition is used in consideration of real manufacturing process, and the material properties for the Mooney-Rivlin model is obtained by the experimental results. The result interpretations are focused on the contact forces, which is displayed graphically with respect to friction coefficient, on the surfaces between the hose and the metal fittings.

• 한국가스학회:학술대회논문집
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• 2007.04a
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• pp.180-185
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• 2007

Likelihood analysis was used for the revision of release probability/frequency in chlorine Injection facilities used in chlorine process. Typically these facilities consist of pressure cylinder, vaporizer, pipeline, measuring equipment and safety equipment. This paper described the incident scenarios considered, likelihood analysis procedure and the selection and application of basic events and for failure rates of mechanical components. Human errors were also considered. The major objective of this paper is to estimate the likelihood of each determined incident scenarios. We estimated failure rates of mechanical components based on likelihood analysis procedure. Human errors were also considered. It was estimated to have $5.73{\times}10^{-5}\;Cl_2$ leak per year during the major $Cl_2$ handling process. The probability of failure in scrubber system was $4.11{\times}10^{-2}/demand$.

• IE interfaces
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• v.24 no.3
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• pp.187-195
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• 2011

The automatic radiopharmaceutical module consists of several 2-way valves, couple of syringes, gas supply unit, heating(cooling) unit and sensors to control the chemical reagents as well as to help the chemical reaction. In order to control the actuators of radiopharmaceutical module, the process is tabulated using spread sheet as like excel. Unlike the common program, a trivial error is too critical to allowed in the process because the error can lead to leak the radioactive reagent and to cause the synthesis equipment failure during synthesizing. Hence, the synthesis process has been validated using graphic simulation while the operator checks the whole process visually and undergoes trial and error. The verification of the synthesis process takes a long time and has a difficulty in finding the error. This study presents a methodology to verify the process algebraically while the radiopharmaceutical module is converted to the network model. The proposed method is validated using actual synthesis process.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.643-658
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• 2015

This study presents detailed emission of greenhouse gases of using Clean Energy Agriculture System according to a cradle-to-gate life-cycle assessment, including emission from energy use and leak of Biogas. Calculations were done with the PASS software and the covered gases are $CH_4$, $N_2O$ and $CO_2$, Total GHG fluxes of amount to $1719.03kgCO_2/day$, $39.63kgCO_2/day$ (2.31%) are from facility house process, $0.19kgCO_2/day$ (0.01%) are from transport process, $696.72kgCO_2/day$ (40.53%) are from Anaerobic digestion process, $846.61kgCO_2/day$ (49.25%) are from Heating and cooling system, $135.88kgCO_2/day$ (7.90%) are from Fertigation production process. The results suggest that for effective reduction of GHG emissions from Facility house using clean energy. Reduction targets should address both the production process as defined by IPCC sectors and the consumption process. An LCA assessment as presented here could be a basis for such efforts.