• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.45-45
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• 2017

The Indian meal moth, Plodia interpunctella, is one of the most important pests of stored food in the food processing industry worldwide. To control the Indian meal moth, methyl bromide, phosphine, high carbon dioxide, sulfuryl fluoride and plant essential oil fumigation have been considered. However, these treatments have disadvantages. For example, depleting the ozone layer, showing resistance in insect, low control efficacy or need high cost for treatment. Chlorine dioxide ($ClO_2$) is strong disinfectant and insecticide. The gas caused a malfunction in enzymes. The oxidative stress induced by $ClO_2$ gas treatment damaged to a physiological system and all life stages of P. interpunctella. The gaseous $ClO_2$ is a convincing alternative to methyl bromide for controlling P. interpunctella. The gaseous $ClO_2$ was generated by a chlorine dioxide generator (PurgoFarm Co., Ltd., Hwasung, Korea). It generated highly pure $ClO_2$ gas and the gas blown out through a vent into a test chamber. Gas entry to the chamber was automatically controlled and monitored by a PortaSene II gas leak detector (Analytical Technology, Collegeville, PA, USA). The properly prepared eggs, larvae, pupae, and adults of P. interpunctella were used in this experiment. Data were analyzed using SAS 9.4. Percentage data were statistically analyzed after arcsine-root transformation. Analysis of variance was performed using general linear model, and means were separated by the least significant difference test at P < 0.05. Fumigation is an effective management technique for controlling all stages of P. interpunctella. We found that $ClO_2$ gas treatment directly effects on egg, larvae, pupae and adults of P. interpunctella. The gas treatment with proper concentration for over a day achieved 100 % mortality in all stages of P. interpunctella and short time treatment or low concentration gas treatment results showed that the egg hatchability, pupation rate, and adult emergency rate were lowered compare with untreated control. Also, abnormal pupae or adult rate were increased. Gaseous $ClO_2$ treatment induced insecticidal reactive oxygen species (ROS), and it resulted in fatal oxidative stress in P. interpunctella. Taken together, these results showed that exposure proper concentration and time of the gas control all stages of P. interpunctella by inducing fatal oxidative stress. Further studies will be required to apply the gas treatment under real-world condition and to understanding physiological reaction in P. interpunctella caused by oxidative stress.

• Journal of the Korean Institute of Gas
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• v.22 no.2
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• pp.90-96
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• 2018

Design techniques for minimizing the damage caused by leakage of $H_2S$ gas, contained in natural gas and petroleum, have been widely studied abroad in chemical plants that purify and process natural gas and petroleum. However, there is no domestic engineering practice and regulation of $H_2S$. In accordance with the circumstances, this study proposes the quantitative criteria of process equipment to install $H_2S$ toxic gas detector as 500 ppm and explains the valid basis. The $H_2S$ gas dispersion radius up to IDLH 100 ppm is calculated by ALOHA under previous $H_2S$ gas leak accident scenario. The weather conditions of modeling include the conditions of Ulsan, Yeosu and Daesan, the three major petrochemical complexes in Korea. The long radius up to 100 ppm was derived in order of Ulsan, Daesan, Yeosu. For emergency safety the dispersion radius up to 100 ppm of the $H_2S$ gas obtained in this study should be extended to apply the additional $H_2S$ toxic gas detector, and local climate conditions should be considered.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.2
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• pp.48-55
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• 1999

Performance analysis of a 50KW turbo-generator gas turbine engine with a recuperator was studied. Recuperated cycle has been employed to meet maximum fuel economy and ultra low emissions especially for military and vehicular engines. From thermodynamic stand point, it is known that recuperative cycle can contribute most to enhance thermal cycle efficiency for the Pressure ratios under 10 and of comparatively low turbine inlet temperature. Efficiency of a simple cycle with a recuperator increases relatively about 30% than without one at effectiveness of 0.5. Pressure losses in the heat exchanger less than 5.2% is considered in the design process. A tubular type heat exchanger is selected for this particular engine because it can provide simple construction as well as structural sturdiness and excellent leak tightness.

• Journal of the Korean Institute of Gas
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• v.12 no.4
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• pp.8-13
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• 2008

The stray current interference problem could induce the corrosion of near-by structure and rail itself. Many efforts has been concentrated on the reduction of the interference. In this work the influences of separation distance, soil resistivity, pipe coating resistance, leak resistance of rail were studied using the numerical analysis methods. These analysis could be used to estimate the sensitivity of each variables in the study of the mitigation method and their numerical analysis.

• Journal of the Korea Safety Management & Science
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• v.19 no.3
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• pp.1-9
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• 2017

In the industrial field, various type of fuel have been used for product processing facilities. Recent for 10 years, the usage of natural gas (NG) was gradually increased. Because it has many merits; clean fuel, no transportation, storage facility and so on. There are common safety concept that strict explosion protection approaches are needed for facilities where explosive materials such as flammable liquid, vapor and gases exist. But some has an optimistic point of view that the lighter than air gases such as NG disperse rapidly, hence do not form explosion environment upon release into the atmosphere, many parts has a conventional safety point of view that those gases are also inflammable gases, hence can form explosion environment although the extent is limited and present. In this paper, the heating equipments (Hot Oil Heater) was reviewed and some risk management measures were proposed. These measures include hazardous area classification and explosion-proof provisions of electric apparatus, an early gas leak detection and isolation, ventilation system reliability, emergency response plan and training and so on. This study calculates Hazardous Area Classification using the hypothetical volume in the KS C IEC code.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.98-103
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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.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.110-118
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• 2002

During the last ten years, the need has been increase for reducing maintenance cost for aged equipments are ensuring safety, efficiency and profitability of petrochemical and refinery plants. American Petroleum institute(API) developed a code, API 581 for proposing standard procedures of risk based inspection. Even though the API 581 code covers general RBI procedures, there must be some limitations. In this study, a semi-quantitative assessment algorithm for RBI based on the API 581 code was reconstructed for developing an RBI software. The user-friendly realRBI software is developed with a module for evaluation semi-quantitative risk category using the potential consequence factor and the likelihood factor. Also, inspection planning module for inspection time and inspection method for equipments are included.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2880-2886
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• 2020

A small leak occurring on the surface of a fuel rod due to damage exposes UO₂ to a steam atmosphere. During this time, fission gas trapped inside the fuel rod leaks out, and the gas leakage can be increased due to UO₂ oxidation. Numerous studies have focused on the steam oxidation and its thermodynamic calculation in UO₂. However, the thermodynamic calculation of the UO₂ oxidation in a pressurized water reactor (PWR) environment has not been studied extensively. Moreover, the kinetics of the oxidation of UO₂ pellet also has not been investigated. Therefore, in this study, the thermodynamics of UO₂ oxidation under steam injection due to a damaged fuel rod in a PWR environment is studied. In addition, the diminishing radius of the UO₂ pellet with time in the PWR environment was calculated through an experiment simulating the initial time of steam injection at the puncture.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.293-300
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• 2022

During the decommissioning of the nuclear facilities, the radioactive gases in pressure vessels may leak due to the demolition operations. The decommissioning site has large space, slow air circulation, and many large nuclear facilities, which increase the difficulty of workers' inhalation exposure assessment. In order to dynamically evaluate the activity distribution of radionuclides and the committed effective dose from inhalation in nuclear decommissioning environment, an inhalation exposure assessment method based on the modified eddy-diffusion model and the inhaled dose conversion factor is proposed in this paper. The method takes into account the influence of building, facilities, exhaust ducts, etc. on the distribution of radioactive gases, and can evaluate the influence of radioactive gases diffusion on workers during the decommissioning of nuclear facilities.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.3
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• pp.573-580
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• 2024

Recently, the special alloy, for instance, such as Monel and Inconel, is used for valves, bolt/nuts, and fittings in semiconductor facility, FCEV(fuel cell electric vehicle) and hydrogen gas station, to reduce the hydrogen embrittlement. Even though the Monel material has high cost, it is recommended to use for the cases of ultra high pressure, ultra high leak-proof and so on. The purpose of this study is to investigate the characteristics of Monel material within elastic limit through the comparative analysis when Monel material is extruded or drawn. As the results, the deformation of Monel material was increased as the number of pass was increased, further, the deformation of Monel material by drawing was larger than that by extrusion. In the safety factor, the case that load is less than 420kN, the plastic deformation due to drawing could be happened faster than that due to extrusion. However, the case of more than 420kN, it showed that the plastic deformation for extrusion and drawing was almost similar.