• Journal of Korean Society of Environmental Engineers
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• v.33 no.4
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• pp.251-257
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• 2011

In the present study, a 3-dimensional (3D) numerical model was developed to mimic the micro porous structure of a geological $CO_2$ storage reservoir. Especially, 3D modeling technique assigning random pore size to a 3D micro porous structure was devised. Numerical method using CFD (computational fluid dynamics) was applied for the 3D micro porous structure to calculate supercritical $CO_2$ flow field. The three different configurations of 3D micro porous model were designed and their flow fields were calculated. For the physical conditions of $CO_2$ flow, temperature and pressure were set up equivalent to geological underground condition where $CO_2$ fluid was stored. From the results, the characteristics of the supercritical $CO_2$ flow fields were scrutinized and the influence of the micro pore configuration on the flow field was investigated. In particular, the pressure difference and consequent $CO_2$ permeability were calculated and compared with increasing $CO_2$ flow rate.

• Structural Engineering and Mechanics
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• v.83 no.5
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• pp.627-644
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• 2022

In past major earthquakes (1994 Northridge, 1995 Kobe, Chi-Chi 1999, Kocaeli 1999), significant damages occurred in the liquid storage tanks. The basic failure patterns were observed to be the buckling of the tank wall and uplift of the anchorage system. The damages in the industrial facilities and nuclear power plants have caused the spread of toxic substances to the environment and significant fires. Seismic isolation can be used in liquid storage tanks to decouple the structure and decrease the structural demand in the superstructure in case of ground shaking. Previous studies on the use of seismic isolation systems on liquid storage tanks show that an isolation system reduces the impulsive response but might slightly increase the convective one. There is still a lack of understanding of the seismic response of seismically isolated liquid storage tanks considering the fluid-structure interaction. In this study, one broad tank, one medium tank, and one slender tank are selected and designed. Two- and three-dimensional elastomeric bearings are used as seismic isolation systems. The seismic performance of the tanks is then investigated through nonlinear dynamic time-history analyses. The effectiveness of each seismic isolation system on tanks' performance was investigated. Isolator tension forces, modal analysis results, hydrodynamic stresses, strains, sloshing heights and base shear forces of the tanks are compared. The results show that the total base shear is lower in 3D-isolators compared to 2D-isolators. Even though the tank wall stresses, and strains are slightly higher in 3D-isolators, they are more efficient to prevent the tension problem.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.7-14
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• 2019

The type III vessel, which is used to store high-pressure hydrogen gas, is made by wrapping the vessel's liner with carbon fiber composite materials for strength performance and lightening. The liner seals the internal gas and the composite resists the internal pressure. The properties of the fiber composite material depends on the angle and thickness of the fiber. Thus, engineers should consider these various design variables. However, it significantly increases the design cost due to the trial and error under designing based on experience or experiments. And, for aluminum liners, fatigue loads due to using and charging could give a huge impact on the performance of the structure. However, fatigue failure does not necessarily occur in the position under the highest load in use. Therefore, for hydrogen storage vessel, fatigue evaluation according to design patterns is essential because stress distribution varies depend on composite layer patterns. This study performed an optimization analysis and evaluated a high-pressure hydrogen storage vessel to minimize these trial and error and improve the reliability of the structure, while simultaneously conducting fatigue assessment of all patterns derived from the optimization analysis process. The results of this study are thought to be useful in the strength improvement and life design of composite reinforced high-pressure storage vessels.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1218-1231
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• 2008

Recently the energy dependence of LNG resource is being increased. So the enlargement of LNG storage is constructed in the coastal area. Most of LNG tanks are constructed below the ground level, and thus the hydraulic uplift pressure could be a problem against the weight of tank structure. Specifically, the settlement of foundation soil in the LNG tank is also important in the aspect of safety. The low temperature around LNG tank is induced the ground freezing and hence increasing the soil volume and earth pressure. The additional lateral earth pressure due to ground freezing could be applied to the LNG tank. In this study, the stability of LNG storage tank was evaluated with consideration of freezing earth pressure by using computer program TEMP-W.

• Earthquakes and Structures
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• v.2 no.4
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• pp.397-412
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• 2011

In this paper, the seismic response of elevated broad and slender liquid storage tanks isolated by elastomeric or sliding bearings was investigated. The accuracy of predictions of SAP2000 vs. 3D-BASIS-ME programs was examined. A comparative study of the performance of base isolated tanks when isolation bearings are placed at the top or at the bottom of the supporting tower structure was conducted. It was found that base isolation is quite effective in reducing the earthquake response of elevated liquid storage tanks in which high reductions of base shear and shaft displacement were achieved. Modeling the isolated tanks in SAP2000 was very successful in producing results that are nearly identical to those of program 3D-BASIS-ME. Placing the isolators at the top of the shaft in elevated tanks proved to be much better than placing them at the bottom.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.528-537
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• 1996

Qualify changes of microwave-reheated cooked rice aseptic-packaged with different lid materials and oxygen absorbers were determined during storage at $20^{\circ}C,\;30^{\circ}C$ and $40^{\circ}C$. Springiness cohesiveness and adhesiveness increased as storage temperature increased, while gumminess and hardness decreased. Lid materials oxygen absorbers, and storage temperatures showed no significant effect on the textural properties of cooked rice after microwave reheating. Degree of gelatinization was increased as storage temperature increased and was restored after microwave reheating. Scanning electron micrograph showed that the surface of cooked rice became rough and hollowed after microwave reheating for 1.5 min, indicating starch was regelatinized, while there was no difference with respect to lid materials. Photomicrographs of the cross-section of aseptic-Packaged cooked rice showed that a compact and solid structure increased and retrogradation occured in starch as storage temperature decreased, while a compact and solid structure was decreased and starch was regelatinized after microwave reheating.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.352-357
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• 2002

In recent years, the demand of mobile device, such as digital camera, camcoder and PDA, increases remarkably. So, requirements of the mobile information data storage used in the mobile devices increase noticeably also. 1' micro data storage is a kind of mobile storage ,which has a CF type II form factor, and the similar structure of the general 3.5' HDD. In this paper, we performed the vibration analysis of the 1' micro data storage, such as measurement of the NRRO of the disck, and modal analysis.

• Journal of Powder Materials
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• v.15 no.3
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• pp.188-195
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• 2008

Carbon nanotube (CNT)/$Mg_2Ni$ composites were synthesized to enhance the hydrogen storage properties. The emphasis was made on the effect of different shortening methods of CNTs on the open-tip structure and the resulting properties. The use of open CNTs as a starting material resulted in an enhanced hydrogen properties of CNT/$Mg_2Ni$ composites. Among the employed methods for the shortening of CNTs, wet milling using ethanol was the most efficient, while ultrasonic acid treatment or thermal decomposition resulted in a less hydrogen storage capacity.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.3
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• pp.1-16
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• 2006

The purpose of this study is to develop design model of ecological park as stormwater storage facilities. The results are as follows : First, the design model of ecological park as stormwater storage facilities consider ecological and landscape characteristics such as high efficiency of land use, function as disaster prevention, ecological water purification, formation of habitat for flora and fauna. Second, this study demonstrates two types of plane structure and eight types of designed section. They can be combined and designed depending on conditions of each site. The facilities of stormwater storage conduct disaster prevention system and ecological park. Retention pond in stormwater storage facilities for ecological park also should be made for ecological restoration in the site. Third, the ecological park provide the basis for ecological network from in-site to out-site. Therefore its conservation and restoration plan consider the ecosystems of the site. Fourth, the most important factor for maintenance and management for retention pond is keeping water quality. Sustainable Structured wetland Biotop system is suggested for ecological water purification system in the retention pond which is one of the constructed wetland system using multi-celled aquatic plant and pond. This system can also provide habitat for animals and plants, water friendly park for men, and beautiful landscape.

• Journal of Ginseng Research
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• v.22 no.2
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• pp.82-90
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• 1998

In order to stabilize the price of fresh ginseng by extension of seasonal variation and marketing structure, and to reduce the cost of production by works of intensive and short term, studies were carried out. As fresh ginseng of 4 years old by the MA and CA was stored for 12 week at 4$^{\circ}C$, samples were collected after every 1, 2, 3, 4, 6, 8, 12 weeks for processing red ginseng. Color and Sensual characteristics on ginseng steamed red for the quality evaluation are summarized as follows. For the time course of storage with red ginseng, which was processed from fresh one after various treatments, L and b values were decreased, however a value was increased. In particular, absorbance was step-wisely increased. Turbidity was somewhat increased, and non-treatment of preservative were shown 2 times higher of absorbance. Extraction ratio of ethanol-soluble extractives slightly increased by the preservation methods, and as storage period was passed. CA storage and preservative treat merit versus MA and non-preservative treatment gave much stability in ginseng quality. In the sensual characters, sour taste and sweet taste were increased, but fresh taste and rice scorched taste were decreased. Bitter taste was not much changed until end of storage. CA was shown smaller differences than MA in the pH change. Addition of preservative extended the storage time.