• Journal of the Korean Geosynthetics Society
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• v.12 no.4
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• pp.67-76
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• 2013

Landfill require special care due to the dangers of nearby surface water and underground water pollution caused by leakage of leachate. The leachate does not leak due to the installation of the geomembrane but sharp wastes or landfill equipment can damage the geomembrane and therefore a means of protecting the geomembrane is required. In Korea, in accordance with the waste control act being modified in 1999, protecting the geosynthetics liner on top of the slope of landfill and installing a drainage layer to fluently drain leachate became mandatory, and technologies are being researched to both protect the geomembrane and quickly drain leachate simultaneously. Therefore, this research has its purpose in studying the drainage functions of leachate and protection functions of the geomembrane in order to examine the application possibilities of Geo-Multicell-Composite (GMC) as a Leachate Collection Removal and Protection System (LCRPs) at the slope on top of the geomembrane of landfill by observing methods of inserting filler with high-quality water permeability at the drainage net. GMC's horizontal permeability coefficient is $8.0{\times}10^{-4}m^2/s$ to legal standards satisfeid. Also crash gravel used as filler respected by vertical permeability is 5.0 cm/s, embroidering puncture strength 140.2 kgf. A result of storm drain using artificial rain in GMC model facility, maxinum flow rate of 1,120 L/hr even spray without surface runoff was about 92~97% penetration. Further study, instead of crash gravel used as a filler, such as using recycled aggregate utilization increases and the resulting construction cost is expected to savings.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.231-240
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• 2017

Recently, there have been frequent occurrences of ground sink in the urban area, which have resulted in human and material damage and are accompanied by economic losses. This is caused by artificial factors such as soil loss, poor compaction, horizontal excavation due to the breakage of the aged sewage pipe, and lack of water proof at vertical excavation. The ground sink can be prevented by preliminary restoration and reinforcement through exploration, but it can be considered that it is not suitable for urgent restoration by the existing method. In this study, a model experiment was carried out to simulate the in-ground cavities caused by groundwater flow for developing non-excavation urgent restoration in underground cavity and the range of the relaxation zone was estimated by detecting the around the cavity using a relaxation zone detector. In addition, disturbance region and relaxation region were separated by injecting gypsum into cavity formed in simulated ground. The shape of the underground cavity due to the groundwater flow was similar to that of the failure mode III formed in the dense relative density ground due to water pipe breakage in the previous study. It was confirmed that the relaxed region detected using the relaxation zone detector is formed in an arch shape in the cavity top. The length ratio of the relaxation region to the disturbance region in the upper part of the cavity center is 2: 1, and it can be distinguished by the difference in the decrease of the shear resistance against the external force. In other words, it was confirmed that the secondary damage should not occur in consideration of the expandability of the material used as the injecting material in the pre-repair and reinforcement, and various ground deformation states will be additionally performed through additional experiments.

• Korean Journal of Food Science and Technology
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• v.40 no.6
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• pp.707-711
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• 2008

The principal objective of the current study was to isolate a purpurogallin derivative as an oxidation product from gallic acid, in an effort to assess the anti-inflammatory effects of this compound. Purpurogallin derivative is known to be the one of the oxidation products of gallic acid. This compound has been identified as a minor chemical component in fermented tea products. It has been previously demonstrated that theaflavins, the oxidation products of catechins found in fermented tea products, exert profound antioxidant and anti-inflammatory effects. However, the biological activities of a minor chemical component in fermented teas have yet to be evaluated. Purpurogallin carboxylic acid (PCA) was identified as a major oxidation product of gallic acid from a peroxidase/hydrogen peroxide oxidation model system. The identity of the PCA was verified by $^{1}H$ NMR, $^{13}C$ NMR and MS techniques. PCA treatment significantly suppressed the generation of pro-inflammatory mediators including nitric oxide and IL-6 in lipopolysaccharide (LPS)-stimulated RAW264.7 murine macrophages. According to the nitrite assay, PCA 100, 75, and $50{\mu}g/mL$ treatment dose-dependently inhibited NO production by 57.6, 41.5, and 21.8%, respectively, in LPS-stimulated RAW264.7 murine macrophage cells. Moreover, IL-6 production was inhibited to a significant degree with PCA treatment of 100 and $75{\mu}g/mL$ at 43.1 and 23.9%, respectively. PCA treatment also significantly suppressed $PGE_2$ production at levels of 100 and $75{\mu}g/mL$. These results showed that PCA exerts inhibitory effects on the production of inflammatory mediators.

• Journal of the Korean Geosynthetics Society
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• v.13 no.2
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• pp.1-10
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• 2014

In this study, two different types of dredged fill injection methods are introduced and filling experiments were conducted to analyze the impact of each technique to the distribution and deposition of dredged soil fill and how it influence the final tube shape. Two transparent plastic tubes were fabricated to observe the deposition behavior of the deposited fill material. Both tubes measured 4.0 meters in length (L) and has vinyl tube diameters (D) of 0.5m and 0.7m. T-type and I-type inlet system are also introduced in this paper. The influence of this inlet systems to the distribution and deposition behavior of dredged soil fill inside the vinyl tubes were observed during the experiment. After the sedimentation of the slurry mixture, the water on top of the soil sediments are removed and the slurry mixture was re-injected into the vinyl tube, this process was carried out repeatedly. The shape changes of the vinyl tube, e.g. the changes in both tube height and width, are constantly monitored after each slurry injection and water draining phases. Crater formation was observed in the case of I-Type inlet system and a non-uniform sediment distribution occurred. For the diffusion deposit of soil particles to long distance are minimal shape technique using the T-Type inlet system. Therefore the undrain filling height ratio ($H/D_0$) was found to be around 0.54 to 0.64 and the horizontal strain ratio ($W/D_0$) ranges from 1.45 to 1.54. The filling soil height is proportional to dredged-material filling phases, but, horizontal strain ratio is constant or inversely reduced so that the center of tube body is raised in the upward direction.

• Journal of the Korean Geosynthetics Society
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• v.20 no.2
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• pp.23-33
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• 2021

In Korea, many reservoirs have been built for the purpose of solving the food shortage problem and supplying agricultural water. However, the current 75.6% of the reservoirs are in serious aged as more than 50 years have passed since the year of construction. In the case of such an aging reservoir, the stability due to scour and erosion inside the reservoir is very reduced, and if concentrated rainfall due to recent abnormal weather occurs, the aging reservoir may collapse, leading to a lot of damage to property and human life. Accordingly, each agency that manages aging reservoirs uses Ordinary Portland Cement (OPC) as an injection material and applies the grouting method. However, in the case of OPC, it may deteriorate over time and water leakage may occur again. And there are environmental problems such as consumption of natural resources and generation of greenhouse gases. So, there is a need to develop new materials and methods that can replace the OPC. In this study, an laboratory test and analysis were performed on the grout material developed to induce a curing reaction similar to that of OPC by recycling power plant byproduct. In addition, test in the field such as electric resistivity survey, Standard Penetration Test (SPT), and field permeability test were performed to analyzed to reinforcement effect and determine the possibility of using instead of OPC. As a results of the test, in the case of recycled power plant byproduct, the compressive strength was 2.9 to 3.2 times and the deformation modulus was 2.3 to 3.3 times higher, indicating that it is excellent in strength and can be used instead of OPC. And it was analyzed that the N value of the reservoir was increased by 1~2, and the coefficient of permeability (k) decreased to the level of 8.9~42.5%. showing sufficient reinforcing effect in terms of order.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.85-93
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• 2021

The seventy percentage of Korean Peninsular is covered by the mountainous area, and the depth of west sea and south sea is relatively shallow. Therefore, a large scale land reclamation from the sea has been implemented for the construction of industrial complex, residental area, and port and airport facilities. The common problem of reclaimed land is consisted of soft ground, and hence it has low load bearing capacity as well as excessive settlement upon loading on the ground surface. The hollow concrete block has been used to reinforce the loose and soft foundation soil where the medium-high apartment or one-story industrial building is being planned to be built. Recently the earthquakes with the magnitude of 4.0~5.0 have been occurred in the west coastal and southeast coastal areas. Lee (2019) reported the advantages of hollow concrete block reinforced shallow foundation through the static laboratory bearing capacity tests. In this study, the dynamic behavior of hollow concrete block reinforced sandy ground with filling the crushed stone in the hollow space has been investigated by the means of shaking table test with the size of shaking table 1000 mm × 1000 mm. Three types of seismic wave, that is, Ofunato, Hachinohe, Artificial, and two different accelerations (0.154 g, 0.22 g) were applied in the shaking table tests. The horizontal displacement of structure which is situated right above the hollow concrete block reinforced ground was measured by using the LVDT. The relative density of soil ground are varied with 45%, 65%, and 85%, respectively, to investigate the effectiveness of reinforcement by hollow block and measured the magnitude of lateral movement, and compared with the limit value of 0.015h (Building Earthquake Code, 2019). Based on the results of shaking table test for hollow concrete block reinforced sandy ground, honeycell type hollow block gives a large interlocking force due to the filling of crushed stone in the hollow space as well as a great interface friction force by the confining pressure and punching resistance along the inside and outside of hollow concrete block. All these factors are contributed to reduce the great amount of horizontal displacement during the shaking table test. Finally, hollow concrete block reinforced sandy ground for shallow foundation is provided an outstanding reinforced method for medium-high building irrespective of seismic wave and moderate accelerations.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.3
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• pp.247-258
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• 2023

This study aims to investigate the enhancement of water resistance and improvement in adhesion to the skin by combining dextrin palmitate and isopropyl titanium triisostearate coating materials with titanium dioxide. Due to the recent increase in consumers who enjoy outdoor activities, the demand for sunscreen with excellent water resistance is increasing. Prior research was conducted with O/W, Pickering, and W/O/W multiple formulations, but there was a limit to water resistance. The purpose of this study is to develop a complex inorganic powder that can improve water resistance and increase adhesion to the skin to solve this problem. First, we combined dextrin palmitate and isopropyl titanium triisostearate coating materials to form a composite with titanium dioxide. The coating of the inorganic powder was confirmed using FE-SEM and FT-IR analysis. The composite exhibited significantly higher in vitro water resistance compared to other formulations. The hydrophobicity of the coated inorganic powder was compared by measuring the contact angles. When the coated inorganic powder was applied to the W/O sunscreen formulation and the non-coated inorganic powder was applied to the W/O sunscreen formulation as a control, the SPF of the sunscreen containing the coated inorganic powder was higher. These results were the same when observed with a UV camera. Finally the adhesion of the coated inorganic powder to the skin was assessed by applying it to a foundation product. In vivo study, it was observed that the product formulated with the coated powder exhibited less smudging compared to the foundation product formulated with the non-coated powder. The developed inorganic powder in this study demonstrated excellent adhesion to the skin, providing a superior sensory experience, as well as enhanced hydrophobicity and remarkable water resistance effects. In the future, the result of this study is expected to help develop various sunscreen products to improve water resistance.

• Bulletin of Food Technology
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• v.26 no.3
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• pp.178-187
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• 2013

분자단계에서 천연소재 유래 다당체는 면역 세포 표면(예, 대식세포)에 있는 한가지 또는 여러가지 수용체(${\beta}$-glucan 수용체, mannose 수용체, complement 수용체 3, Toll-like 수용체, scavenger 수용체)와 면역 반응을 시작하기 위하여 결합할 수 있고, 그 후에 신호전달을 위하여 cytokine과 second messenger($Ca^{2+}$, cAMP, cGMP, NO 등등)들을 생성한다. 그 결과로 선천면역과 적응면역을 유도하여 다양한 질환에 영향을 미친다. 추가적으로 다당체들의 면역조절은 신경내분비 체계의 조절과도 연관되어 있다. 최근 수많은 천연소재유래 다당체의 생리활성에 관한 연구가 진행되고 있다. 다양한 연구를 통해 정확한 약효, 낮은 독성과 부작용을 가진 일단의 다당체가 발견되어 현재 임상에서 암 치료에도 사용되고 있다. 이러한 사실들은 면역증진 다당체들이 항 종양치료를 위한 새로운 치료제로서 큰 시장을 개척할 수 있다는 가능성을 보여주고 있다. 이러한 사실에도 불구하고 현재 다당체에 대한 연구는 다음과 같은 취약점을 내포하고 있다. 첫째 다당체의 생리활성에 대한 정해진 비교기준이 없다. 특별히 임상 환경에서는 이러한 연구들이 중국, 일본, 한국과 일부 다른 동양국가들에 국한되어 있어 유럽이나 미국에서의 연구 자료가 결여되어있다. 둘째 현재 연구에 사용되고 있는 대다수의 천연소재 유래 다당체는 순수한 다당체가 아닌 천연 그대로의 것을 사용하고 있어 소재로부터 유래하는 다른 활성성분에 의해 쉽게 영향을 받을 수 있어 순수 다당체가 면역체계에 어떠한 역할을 수행하는지 진단하는데 어려움이 있다. 셋째 면역조절 경로에서 다당체의 정확한 신호전달 경로가 아직 정확하게 밝혀지지 않았고, 또한 동물과 임상실험에서 다당체가 작용하는 수용체 및 신호전달 경로에 대한 상반되는 결과가 발표되고 있기도 하다. 따라서 다당체의 면역조절활성에 대한 연구에 있어 다음과 같은 점들에 주목해야 할 필요가 있다. 첫째 다당체의 구조와 활성간의 상관관계를 밝혀야 할 것이다. 특히 다당체의 세부 구조 및 활성 부위를 밝혀낸다면 분자수준의 면역조절 기작을 명확히 하는데 도움을 줄 수 있을 것이다. 이러한 정보를 확보할 수 있다면 다당체의 구조를 변형시켜 활성을 증진시킬 수 있을 것이며, 또한 활성이 증가된 다당체를 합성하는 일도 가능해 질 것으로 예상된다. 마지막으로 ${\beta}$-glucan과 lentinan과 같은 정제된 다당체의 연구를 지속적으로 수행하여 효과적인 동물실험 및 임상실험 protocol을 확보하고 연구결과들에 대한 database를 구축해야 할 필요가 있다. 이러한 노력들이 성공적으로 수행된다면 천연소재유래 다당체들이 가까운 장래에 암 치료를 포함한 다양한 질병에 적용 가능한 새로운 면역조절제로 사용될 수 있을 것이다.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.12 s.148
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• pp.1554-1561
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• 2005

This study aims to analyze modern hairstyle and fashion in the collections in the late 1990s, based on the concepts and characteristics of Minimalism, a buzzword of the art field in the 1960s. This study used qualitative research method, in other words, presenting an analysis framework by studying domestic and foreign books and dissertations on Minimalism and then applying the Internet or visual image to the analysis framework. The result indicates that Minimalism design in modem hairstyle and fashion has four characteristics: simplicity, unity, repetition and spatiality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.86-93
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• 2020

The demand for maintenance in Korea infrastructure facilities constructed since the 1970s has increased significantly compared to the demand for new construction. Moreover, after the Gyeongju and Pohang earthquakes, seismic performance evaluation, repair, and retrofitting projects have been carried out. Therefore, in this study, a specimen was designed following the L-type GFRP Plate Externally Bonded Retrofit method, one among other retrofit methods. The L-type GFRP Plate was bonded to the specimen by epoxy and a washered steel nail. A four-point bending test was performed to confirm the strengthening effect of the Externally Bonded Retrofit method using an L-type GFRP Plate. The strengthening effect of the L-type GFRP plate was proven experimentally, and the behavior of the beam designed following the L-type GFRP Plate Externally Bonded Retrofit method was evaluated according to Korea's "Design Manual & Specification for Strengthening of RC Structures by Advanced Composites System". Furthermore, the effectiveness of the bonding method, a combination of epoxy and washered steel nail, was also checked. The results showed that the design, according to the guidelines mentioned above, predicted the strength of the member well, but the failure mode did not satisfy the design assumption because of unexpected damage to the GFRP plate due to the fixing method, washered steel nail.