• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.79-83
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• 2005

In the reinforced concrete structure, Even if speak that water leakage occurrence is no problem to material, there is a lot of reasons construction factor, material damage by behavior structure, properties of matter change by years and water leakage part by environment condition. so, waterproofing technological consideration should be gone ahead. In this research, we will study about stick performance, concrete surface adhesive, damage and blow. we will check all things and test it. The stick expansion type complex of flexible material passed on result of standard. It is conducive to concrete of durability by waterproofing layer performance demobilitation technology on the water leakage structure for solution of problem and repair

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1436-1438
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• 2000

It is one of the most effective methods for improving the performance of electric railway vehicles to make better the wheel-rail adhesion characteristics. To study adhesion characteristic is to develop the equivalent reduction machine to experiment on the adhesion system. The experiment system makes it possible to change the wheel-rail adhesion force with various adhesion parameters, and therewith to test the adhesion control system with the reduction machine in a laboratory. In this paper, for improving adhesion performance shows actually control methods.

• Journal of the Korean Geosynthetics Society
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• v.15 no.2
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• pp.25-33
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• 2016

This study was a basic research to obtain the knowledge of physical properties of the upper sedimented sandy soil in the Nakdong river delta area. The characteristics of shear strength and permeability with fine content and relative density were also investigated. The upper sedimented sandy soil near paddy and lower soft clay layers showed high percentage of fine content, and the rest parts had about 5% of fine content. The specific gravity regardless of depth and location was almost constant. The upper sedimented sandy soil mostly had particle size about 0.1 ~ 0.4mm regardless of sedimentation environment and has illite, a clay mineral, in the entire soil samples. The results of direct shear tests on remolded specimens of the upper sedimented sandy soil revealed that the friction angle and cohesion increased with relative density, but its effect was not significant. The fine content was significant, that as increasing it, the friction angle decreased and cohesion increased linearly. The permeability decreased with relative density and fine content, and the permeability of soil containing more than 15% of fine content was independent on the relative density.

• Journal of the Korean GEO-environmental Society
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• v.11 no.6
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• pp.47-55
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• 2010

The recycled fine aggregates were mixed with weathered granite soils typically used for fill materials and tested engineering properties, physical properties, and compaction characteristics according to the mixing ratio of the mixed soils. The results of this study were as follows. For the results of A-type compaction test, the recycled fine aggregates showed low effects compared to the weathered soils, but the mixed soils which were mixed with the weathered granite soils and the recycled fine aggregates showed good compaction effects. Especially, the mixing ratio of 70:30 by weight showed for maximum compaction result. From the results of the direct shear test, the cohesion was ince csed according to proportion of the weathered granite soils. The weathered granite soils neared the optimum moisture content showed for maximum shear strength paramcoers, while the cohesion of the mixed soil was relatively ince csed in the wet side of the optimum moisture content. This trend was seemed to remained cence composition in the recycled fine aggregates. The internal friction angle of the recycled fine aggregates and the mixed soils showed maximum value near dry side of the optimum moisture contents. And the internal friction angles of the mixed soils were increased according to higher proportion of the recycled fine aggregates.

• Journal of the Korean Geotechnical Society
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• v.32 no.11
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• pp.43-50
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• 2016

A reinforcement is required to ensure the structural safety in case of railway embankment excavation under railway load. A large diameter soil nailing with concrete wall is applied as the reinforcement method instead of the conventional soil nailing system. In this study, a series of 3 dimensional numerical analyses are performed to investigate the optimum reinforcement considering 15 different conditions based on the length, lateral spacing, diameter, and inclination of the reinforcement. The interface between soil nail and perimetric grout is considered by means of cohesion, stiffness and perimeter of the grout. 0.3 m of reinforcement diameter is assessed as the most appropriate based on the economical viewpoint though ground displacement decreases with the increase of diameter, however the difference of displacement is negligible between 0.4 m and 0.3 m of diameter. Surface settlement, lateral displacement of wall, and stress of reinforcement are calculated and economic viewpoint to reinforce embankment considered. Consequently, the optimum reinforcement conditions considering those factors are evaluated as 3 m in length, 0.3 m in diameter, 1.5 m in lateral spacing, and 10 degree of inclination angle in the case of 3 m of excavation depth. Additionally, inclined potential failure surface occurs with approximately 60 degrees from the end of nails and the surface settlement and wall lateral displacement are restrained successfully by the large diameter soil nailing, based on the result of shear strain rate.

• Polymer(Korea)
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• v.24 no.1
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• pp.82-89
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• 2000

The blood compatibilities of PU/PVA polymer blends with different mixing ratios were evaluated using various methods, such as fibrinogen adsorption, plasma recalcification time, platelet adhesion, whole blood clotting time, and complement activation. In addition, PVA on the surface of the polymer blends was crosslinked by glutaraldehyde to restrain the mobility of PVA molecules for characterizing the effect of PVA in the polymer blends on blood compatibility. The fibrinogen adsorption on the polymer blends decreased with the increase of PVA amount in the polymer blends. The plasma recalcification times of the polymer blends with 10-50 wt% PVA were longer than those of PU, PVA, and polymer blends with higher amount of PVA. The morphological changes and adhesion of platelets on the polymer blends with 30-50 wt% PVA were less than those on the other materials. The blood clotting times and complement activation on the polymer blends with 30-50 wt% PVA were reduced, compared to the other materials. On the other hand, the blood compatibility of the crosslinked polymer blends was relatively decreased, compared to the non-crosslinked ones. According to these experimental results, the blood compatibility of the polymer blends with 30-50 wt% PVA was better than that of the other materials and such a blood compatibility of the polymer blends might be related to the mobility of PVA molecules on the surface.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.369-377
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• 2021

Mass trapping of the western flower thrips, Frankliniella occidentalis, has been considered as an option to control this pest. This study applied the commercial lures to the hot pepper-cultivating greenhouses and assessed the enhancement of the attracting efficiency by adding to sticky traps. There was no color difference in the attracting efficiency between blue and yellow sticky traps. However, the installation position of the traps was crucial in the greenhouses. The more thrips were captured within host cropping area than outside areas of the crop. In vertical trap position, it was the most optimal to install the traps at the crop crown. Using these installation parameters, the yellow sticky traps captured approximately 1% population of the thrips. To enhance the trapping efficiency, the commercial lures containing aggregation pheromone or 4-methoxybenzaldehyde were added to the yellow sticky traps. However, these commercial lures did not significantly enhance the trapping efficiency compared to the yellow sticky trap alone. In contrast, Y-tube olfactometry assays confirmed the high efficiency of the aggregation pheromone or another plant volatile (methyl isonicotinate) to attract the thrips. Interestingly, these lure components had lower attracting efficiencies compared to the hot pepper flowers. The high attractive efficiency of the flowers was supported by the observation that the commercial lure was effective to enhance the trapping efficiency of the yellow sticky trap against F. occidentalis in Welsh onion (Allium fistulosum) field without any flowers. This study indicates the limitation of the commercial lures in application to hot pepper fields for the mass trapping of F. occidentalis. It also suggests active volatile component(s) from hot pepper flowers to attract F. occidentalis.

• Food Engineering Progress
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• v.23 no.1
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• pp.62-68
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• 2019

In this study, the physical and sensorial properties of the meat analog were studied for the purpose of improving sensory preference and mimicking animal meat. The meat analog was made with different types of liquid materials such as oil, water, lecithin, polysorbate 80, or the emulsion of these components. At the aspect of density, the sample mixed with oil was higher than the sample mixed with water. Cooking loss value was higher at the sample with water than the sample with oil and this was the result opposite to the liquid holding capacity analysis. Also, texture profile analysis result showed that the samples with medium chain triglycerides (MCT) oil only showed the highest values in all attributes except for adhesiveness. Principal component analysis was carried out to analyze sensorial properties and it showed that the overall acceptance was high when the juiciness and softness increased. This result was highly related with the addition of emulsion. Therefore, emulsion technology can be a good candidate for improving the quality of meat analog and for mimicking the taste of animal meat.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.4
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• pp.349-360
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• 2003

A practical modeling approach has been proposed in this study to better understand the behavior of penetration grouting which is normally applied to the jointed rock masses to increase the bearing capacity and to reduce the ground water flow into the tunnel. Based on Bingham model together with a steady-state flow of the grout, penetration model is simulated in the commercial package called UDEC and, injection pressure as well as joint thickness are found to be the main parameters to determine the range of grout spread. Another numerical model on fracturing grouting is also suggested and, in this case, the tensile strength as well as cohesion of the rock masses are proven to be the major factors to decide the fracturing mechanism of the rock masses. The reinforcement effect of the grout-reinforced rock masses is calculated from the suggested algorithm on orthotropic material model and it is found that the directional stiffness of reinforced rock masses is increased up to 3 to 4 times compared with original jointed rock masses. Future work will be concentrated on the water control around the tunnel by the grout injection and a model test will also be performed to verify the suggested methods developed in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.207-217
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• 1992

In this study, isolated and cultured nitrogen fixed microbes were seeded in the three-phase fluidized bed in which gas, solid and liquid were contacted directly. Input velocity was varied from 8.12 cm/hr to 16.32 cm/hr. And upflow gas pressure was fixed to 80 psi. Return ratios were from 0.2 to 0.6 with the each experimental condition. According to these condition, movement of media, growth of biofilm and removal efficiency were measured. As the results, in case of briquette ash, biofilm was developed to $170{\mu}m$ when velocity was 8.12 cm/hr and return ratio was 0.6. In this condition, COD removal efficiency was 97% and $NH_4$-N removal efficiency was 83%. At the same condition, biofilm thickness of glass bead was $17.59{\mu}m$ and its COD and $NH_4$-N removal efficiency was 83% and 72%. Nitrogen fixed microbes have following characters: it formed dark-brownish sludge, excellent adhesive force, easy solid-liquid separation and low oxygen uptake ratio, but sensitive to DO concentration. Not only it endured shock loading, but required short time to steady state.