• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.285-292
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• 2010

Recently, it is difficult to find a good soil ground due to the shortage of land for new construction site. Because of this situation, the geosynthetics are commonly used for reinforcing the substructure of the soil ground, and hence improving the bearing capacity and reducing the settlement. The geocell is one of geosynthetics and is the advanced system of geogrid. It is the way to increase earth strength and bearing capacity by using three dimension type of geocomposite. In this paper, the Horizontal permeability was determined with considering various geocell shapes. The permeability test was performed by following method of ASTM D4716(87) and potential filling material for geocell was used. The bearing capacity mechanism which enhances the soil ground with evenly maintaining the degree of the compaction was also analyzed for geocell reinforced ground.

• Food Science of Animal Resources
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• v.37 no.1
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• pp.98-104
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• 2017

The objective of this study was to determine the effects of short-term presalting on pink color and pigment characteristics in ground chicken breasts after cooking. Four salt levels (0%, 1%, 2%, and 3%) were presalted and stored for 0 and 3 d prior to cooking. Cooking yield was increased as salt level was increased. However, no significant differences in pH values or oxidation reduction potential (ORP) of cooked chicken breasts were observed. Cooked products with more than 2% of salt level had less redder (lower CIE $a^*$ value) on day 3 than on those on day 0. As salt level was increased to 2%, myoglobin was denatured greatly. Myoglobin denaturation was leveled off when samples had 3% of salt. With increasing salt levels, residual nitrite contents were increased while nitrosyl hemochrome contents were decreased. These results demonstrate that salt addition to a level of more than 2% to ground meat may reduce the redness of cooked products and that presalting storage longer than 3 d should be employed to develop a natural pink color of ground chicken products when less than 1% salt is added to ground chicken meat.

• Journal of the Korean GEO-environmental Society
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• v.22 no.7
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• pp.5-12
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• 2021

The reliable seismic stability evaluation of the natural slopes and geotechnical structures has become a critical factor of the design. Pseudo-static or permanent displacement methods are typically employed to evaluate the seismic slope performance. In both methods, the effect of input ground motion on the sliding surface is ignored, and failure surface from the limit equilibrium method is used. For the assessment of the seismic sensitivity of failure surface, two-dimensional non-linear finite element analyses are performed. The performance of the finite element model was validated against centrifuge measurements. A parametric study with a range of input ground motion was performed, and numerical results were used to assess the influence of ground motion characteristics on the sliding surface. Based on the results, it is demonstrated that the characteristics of input ground motion have a significant influence on the location of the seismically induce failure surface. In addition to dynamic analysis, pseudo-static analyses were performed to evaluate the discrepancy. It is observed that sliding surfaces developed from pseudo-static and dynamic analyses are different. The location of the failure surface change with the amplitude and T_m of motion. Therefore, it is recommended to determine failure surfaces from dynamic analysis

• Journal of the speleological society of Korea
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• no.5
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• pp.25-36
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• 1997

The inside of Woldum cave has a complicated configuration with many dynamic aspects. The number of configurations and natural features of the ground discovered up to now is about 20. When we discuss the value of the potential tourism that the cave has, Woldun cave is a lime cave with resourceful value and tourism value, considering the size of cave and excellency of the spectacular sight. In addition, the large stalagmite's file lining in the inside of the cave is a magnificent spectacle. Therefore the Woldun cave, as a lime cave, is very important for tourism level as well as academic ones.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.7_spc
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• pp.435-441
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• 2016

The Korean peninsula has known as a minor-to-moderate seismic region. However, some recent studies had shown that the maximum possible earthquake magnitude in the region is approximately 6.3-6.5. Therefore, a seismic vulnerability assessment of the existing infrastructures considering ground motions in Korea is necessary. In this study, we developed seismic fragility curves for a continuous steel box girder bridge and two typical transmission towers, in which a set of seven artificial and natural ground motions recorded in South Korea is used. A finite element simulation framework, OpenSees, is utilized to perform nonlinear time history analyses of the bridge and a commercial software, SAP2000, is used to perform time history analyses of the transmission towers. The fragility curves based on Korean ground motions were then compared with the fragility curves generated using worldwide ground motions to evaluate the effect of the two ground motion groups on the seismic fragility curves of the structures. The results show that both non-isolated and base-isolated bridges are less vulnerable to the Korean ground motions than to worldwide earthquakes. Similarly to the bridge case, the transmission towers are safer during Korean motions than that under worldwide earthquakes in terms of fragility functions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1164-1169
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• 2014

Overturning of concrete poles are occurred annually due to natural disaster such as a typhoon. The present code for the resisting moment and the safety on overturning of concrete poles in inclined ground is inadequate. In this study, the concept of the code for those in flat ground is applied to calculate the resisting moment in inclined ground using general analysis program L-Pile Plus13.8. According to the analytical results, the resisting moment in inclined ground is rapidly decrease as increasing the slope angle although the embedded depth are added by the additional embedded depth on the code. It is revealed that the capacity in inclined ground is equivalent to that in flat ground if additional embedded depth is increased from 1.5 to 3 times.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.45-56
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• 2014

Frozen ground in cold region consists of an upper active layer and lower permafrost which is permanently frozen land. During the summer season, the air temperature is high enough to make the frozen ground melt, which causes the reduction of soil strength and thaw settlement. These phenomena result in structural instability, so it is necessary to apply frozen ground stability techniques. Thermosyphon is a closed natural two-phase convection device to maintain the ground temperature below $0^{\circ}C$ by extracting heat from the ground and discharges it into the atmosphere. Experimental and numerical investigation has been performed to estimate the effect of the refrigerant filling ratio in thermosyphon using R-134a refrigerant and the thermal conductance of the thermosyphon.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.9
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• pp.2280-2285
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• 1993

Many items, as internal pressure, thrust, temperature, strain, etc. are measured in Ground Firing Test (GFT) of rocket motors. But these items are influenced by various phenomena occurred during propellant combustion. In this study, natural frequencies of motor itself and system(motor+loadcell) on Stand were measured. Also motor responses were measured during burning and analyzed so that the vibration characteristics occurred during GFT and the causes and characteristics of vibration signal appearing on thrust curve were identified.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.541-546
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• 1998

The objective of this research is to observe the actual response of low-rise nonseismic moment-resisting infilled reinforced concrete frame subjected to varied levels of earthquake ground motions. First of all, the reduction scale for the model was determined as 1 : 5 considering the capacity of the shaking table to be used. This model was, then, subjected to the shaking table motions simulating Taft N21E component earthquake ground motions, whose peak ground accelerations(PGA`s) were modified to 0.12g, 0.2g, 0.3g, and 0.4g. The global behavior and failure mode were observed. The lateral accelerations and displacements at each story and local deformations at the critical portions of structure were measured. Before and after each earthquake simulation test, free vibration tests were performed to find the changes in the natural period of the model.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.427-432
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• 1998

The objective of this research is to observe the actual response of low-rise nonseismic moment-resisting reinforced frame subjected to varied levels of earthquake ground motions. First of all, the reduction scale for the model was determined as 1 : 5 considering the capacity of the shaking table to be used. This model was, then, subjected to the shaking table motions simulating Taft N21E component earthquake ground motions, whose peak ground accelerations(PGA's) were modified to 0.12g, 0.2g, 0.3g, and 0.4g. The global behavior and failure mode were observed. The lateral accelerations and displacements at each story and local deformations at the critical portions of structure were measured. The base shear was measured by using specially made load cells. Before and after each earthquake simulation test, free vibration tests were performed to find the changes in the natural period and damping ratio of the model.