• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.11a
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• pp.159-164
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• 2004

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2011.10a
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• pp.189-190
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• 2011

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.05a
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• pp.149-150
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• 2012

• Journal of Energy Engineering
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• v.14 no.4 s.44
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• pp.268-276
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• 2005

Vacuum Residue (VR) combustion tests were carried out with a 20 kg/hr (fuel feed rate) small scale reactor. The nozzle used was a steam atomized, internal mixing type. Compared to heavy oil, vacuum residue used in this work is extremely high viscous and contains high percentages of sulfur, carbon residue and heavy metals. To ignite atomized VR particles, it was necessary to preheat the reactor, and it has been done with LP gas. The axial and radial gas temperature, major species concentrations and solid sample were analyzed when varying the fuel feed rate. The main reaction zone of atomized VR-air flame in a reactor was anticipated within about 1 m from the burner tip by considering the profiles oi gas temperature, species concentration and particle size measured along with the reactor. At downstream, the thermally, fully developed temperature distribution was obtained. SEM photographs revealed that VR carbon particles collected from the reactor are porous and have many blow-holes on the particle surface.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.601-608
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• 2014

An offshore plant is vulnerable to fire because of the isolated environment. In particular, the damage to an offshore plant is increased when a hydrant reducing valve, which is a main piece of equipment in an offshore plant, is damaged in a fire. In this study, we conducted a fire safety test for a hydrant reducing valve and proved the validity of our analysis by comparing the results of the test and analysis. Therefore, we here suggest an analysis method for a fire safety test. FSI(fluid structure interaction) was considered in the fire safety test. The reliability of the analysis method was verified by comparing the temperature distributions of the test and analysis. In addition, we verified the problems that were caused in the fire safety test by conducting a structure analysis. At a result, the main problem was found to be deformation of the valve seat.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.4
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• pp.303-309
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• 2010

For the pyrochemical process of spent nuclear fuels, recovery of LiCl-KCl eutectic salts is needed to reduce radioactive waste volume and to recycle resource materials. This paper is about recovery of residual LiCl-KCl eutectic salts in radioactive rare earth precipitates (rare earth oxychlorides or oxides) by using a vacuum distillation process. In the vacuum distillation test apparatus, the salts in the rare earth precipitates were vaporized and were separated effectively. The separated salts were deposited in three positions of the vacuum distillation test apparatus or were collected in the filter and it is difficult to recover them. To resolve the problem, a vacuum distillation and condensation system, which is subjected to the force of a temperature gradient at a reduced pressure, was developed. In a preliminary test of the vacuum distillation/condensation recovery system, it was confirmed that it was possible to condense the vaporized salts only in the salt collector and to recover the condensed salts from the salt collector easily.

• Tunnel and Underground Space
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• v.24 no.2
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• pp.143-154
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• 2014

In this study, we simulated both dissociation of gas hydrate and mechanical deformation of hydrate-bearing sedimentary formation using geomechanical model. The geomechanical model analysis consists of two distinct codes of TOUGH+Hydrate and FLAC3D. The model is characterized by the fact that changes of temperature, pressure, saturation and their influence on the consequent evolution of effective stress, stiffness and strength of hydrate-bearing sediments during gas production could be well simulated. We compared the results of simulation for two different production methods, and showed that combination of depressurization and thermal stimulation results in the enhancement of production rate especially at early stage. We also presented that the hydrate dissociation-induced geomechanical deformation in unconsolidated clay is much larger than that in sandstone.

• Journal of Korea Water Resources Association
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• v.33 no.3
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• pp.289-298
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• 2000

In order to minimize the impact of water hammer In a pipeline, a determination of optimum position of hydraulic structures with best operation of pressure relief valve was explored at the Seobyun pumping station. Method of characteristics is used to simulate a surge impact originating from abrupt stop of pumping operation in a pipeline. Genetic algorithm shows a powerful capability in searching a global solution, especially for a nonlinear problem The application results suggests that the maximum positive pressure can be relaxed by decreasing the opening time of pressure relief valve, meanwhile the maximum negative pressure can be relaxed by increasing the opening time of pressure relief valve. This study shows that the integration of a genetic algorithm with a transient analysis technique such as method of characteristic can improve the design of hydraulic structure in a pipe network.

• Elastomers and Composites
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• v.49 no.3
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• pp.199-203
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• 2014

Terpolymer syrups were photopolymerized from 2-ethylhexyl acrylate, 2-hydroxylethyl acrylate and isobornyl acrylate to prepare acrylic pressure sensitive adhesives (PSAs). After polymerization, various crosslinkers as 1,6-hexanediol diacrylate (HDDA), poly (ethylene glycol) diacrylate (PEGDA, Mn = 250, 575, and 700) were added and then UV-irradiated to prepare the semi-IPN type PSAs. Their adhesion performance and storage modulus (G') were strongly dependent on their chemical structure and molecular weight of the crosslinkers. Optical properties such as transmittance (> 92.5 %), haze (< 1.0 %) and color-difference (< 0.3) of PSAs samples were not affected by crosslinker types used in this study.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.393-395
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• 1996

This study was conducted to investigate the effect of infusion of pectinesterase (PE) along with preheating treatment in $CaCI_2$ solution on softening Kimchi tissue. Preheating treatment showed preventive effect on softening of Kimchi tissue. Especially, the preheating in the presence of P was more effective in preserving firmness of both stem and leaf. As for of effect of PE infusion by vacuum treatment, a maximum crispness was obtained from the vacuum-treated stems in 0.05 M $CaCI_2$ solution containing PE. The crispness of all the samples decreased during fermentation and the PE-infused samples by vacuum treatment showed higher crispness than the control until the fourth day of fermentation.