• Title/Summary/Keyword: erosion study

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A Study on Compressive Strength Estimation of Underwater Concrete Structures According to Water Depths (수중 콘크리트 구조물의 수심별 강도 추정에 관한 연구)

  • Lee, Jisung;Han, Sanghun;Park, Seunghee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.3
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    • pp.341-348
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    • 2016
  • Harbor facilities require long-term durability and safety, and also maintain the performance requirement until the durability life. However, existing harbor facilities are becoming superannuated with durable years and durability is declined by erosion of the sea and damage from sea. In addition, harbor facilities will be in demand for the expansion of harbor and offshore structures with rising economic power by enhancement of domestic industry and increase of import and export. Therefore, in this study, two kinds of nondestructive test (NDT) techniques (schmidt rebound hammer and ultrasonic sensor) are verified for the effective maintenance of underwater concrete structures including harbor facilities. Sea field applicability of Schmidt hammer and ultrasonic sensor was verified by comparing field test result with sea field test result and also deduced the compressive strength estimation equation by depth of the water. On the basis of the sea field test result, compressive strength estimation equation which was deduced by multiple regression analysis indicated highest accuracy compared to other equations, especially it will be more likely to be used in underwater because of the depth of water correction. In the future, if schmidt hammer and ultrasonic sensor which were invented as waterproofing are used with ROV (Remotely Operated Vehicle), it will be possible to make a diagnosis of high reliability for underwater concrete structures and set up a ubiquitous concept of NDT system.

New Flood Hazard Mapping using Runoff Mechanism on Gamcheon Watershed (유출메커니즘을 활용한 감천유역에서의 새로운 홍수위험지도 작성)

  • Kim, Tae Hyung;Han, Kun Yeun;Park, Jun Hyung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.6
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    • pp.1011-1021
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    • 2016
  • This study performs the potential flood hazard analysis by applying elevation data, soil data and land use data. The susceptibility maps linked to elevation, soil and land use are combined to develop the new types of flood hazard map such as runoff production map and runoff accumulation map. For the development of the runoff production map, land use, soil thickness, permeability, soil erosion and slope data are used as runoff indices. For the runoff accumulation map, elevation, knick point and lowland analysis data are used. To derive an integrated type of flood potential hazard, a TOPSIS (The Technique for Order of Preference by Similarity to Ideal Solution) technique, which is widely applied in MCDM (Multi-Criteria Decision Making) process, is adopted. The indices applied to the runoff production and accumulation maps are considered as criteria, and the cells of analysis area are considered as alternatives for TOPSIS technique. The model is applied to Gamcheon watershed to evaluate the flood potential hazards. Validation with large scale data shows the good agreements between historical data and runoff accumulation data. The analysis procedure presented in this study will contribute to make preliminary flood hazard map for the public information and for finding flood mitigation measures in the watershed.

Inhibitory Effects of Ssangbohwan on Osteoclast Differentiation and Bone Resorption (쌍보환 추출물의 파골세포 분화 억제와 골 흡수 억제효과)

  • Kim, Seong Joung;Lee, Jeong Ju;Kim, June Hyun;Jo, So Hyun;Park, Min Cheol;Jo, Eun Heui
    • Journal of Acupuncture Research
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    • v.32 no.3
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    • pp.69-81
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    • 2015
  • Purpose : The first purpose of this study is to find out whether the water extract of Rehmanniae Radix Preparat(RRP), Cuscutae Semen(CS) and their combination(Ssangbohwan, SBH) have the effect of suppressing Receptor activator of nuclear factor kappa-B ligand(RANKL)-induced osteoclast differentiation. The second purpose of this study is to find out whether the water extract of RRP, CS and SBH have the effect of inhibiting osteoporosis in an osteoporosis model induced by lipopolysaccharide(LPS). Methods : After promoting differentiation of osteoclasts by treating the RANKL, we observed the effect by the administration of RRP, CS and SBH. In addition, by means of Reverse transcription polymerase chain reaction(RT-PCR), we assayed mRNA expression levels of NFATc1, c-Fos, TRAP and GAPDHS(Glyceraldehyde-3-phosphate dehydrogenase, spermatogeni) from bone marrow macrophages(BMMs). Similarly, the protein expression levels of NFATc1 (Nuclear factor of activated T-cells, cytoplasmic1), C-Fos, MAPKs(Mitogen-activated protein kinases) and ${\beta}$-actin in cell lysates were analyzed by means of Western Blotting. Finally, we determined the anti-osteoporotic effects of RRP, CS and SBH, through the use of Lipopolysaccharide-induced bone-loss mouse. Results : RRP, CS and SBH showed remarkable inhibitive effect on RANKL-treated osteoclast differentiation without cytotoxicity. SBH inhibited the phosphorylation of p38, Jun N-terminal kinases(JNK), and I-${\kappa}B$ and down-regulated the induction of c-Fos and NFATc1 by RANKL. RRP, CS suppressed degradation of I-${\kappa}B$, but it did not affect c-Fos and NFATc1 by RANKL. Lastly, in vivo data showed that RRP and SBH prevented bone erosion by LPS treatment. Conclusions : These results demonstrate SBH can be effective remedy for bone-loss diseases such as osteoporosis.

Inhibitory Effects of Water Extracts of Eucommiae Cortex and Psoraleae Semen Alone and in Combination on Osteoclast Differentiation and Bone

  • Park, Jin Soo;Park, Ga Young;Choi, Han Gyul;Kim, Seong Joung;Kim, June Hyun;park, Min Cheol;Kim, Yun Kyung;Han, Sang Yong;Jo, Eun Heui
    • Journal of Acupuncture Research
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    • v.34 no.2
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    • pp.1-18
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    • 2017
  • Objectives : The purpose of this study was to evaluate the effects of water extracts of Eucommiae cortex (EC), Psoraleae semen (PS), and their combination on receptor activator of nuclear factor-kappa-B ligand (RANKL)-induced osteoclast differentiation. Methods : We assayed the protein expression levels of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), c-Fos, mitogen-activated protein kinases (MAPKs), and ${\beta}-actin$ in cell lysates using western blotting. Similarly, mRNA expression levels of NFATc1, c-Fos, tartrateresistant acid phosphate (TRAP), and glyceraldehyde-3-phosphate dehydrogenase, spermatogeni (GAPDHS) from bone marrow macrophages (BMMs) were analyzed using reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, we determined the anti-osteoporotic effects of the water extracts of EC, PS, and their combination in a lipopolysaccharide (LPS)-induced bone-loss mouse model. Results : The in vitro data revealed showed that the combination of EC and PS extract showed a more remarkable inhibition of osteoclast differentiation than each herb did alone. The combination downregulated the induction of c-Fos, NFATc1, and TRAP by suppressing the phosphorylation of p38 and c-Jun N-terminal kinases (JNKs) and inhibiting nuclear factor kappa-light-chain-enhancer of activated B cells ($NF-{\kappa}B$). Lastly, the in vivo data showed that PS reduced the LPS-induced bone erosion. Conclusion : The result of this study suggests that EC and PS could be potential therapeutic agents for bone loss diseases such as osteoporosis.

A Comparative Study of Pyeongwi-san, Ijin-tang and Pyeongjintang Extracts on Indomethacin-Induced Gastric Mucosal Lesions in Mice (Indomethacin으로 유발된 생쥐의 위점막 손상에 대한 평위산(平胃散), 이진탕(二陳湯) 및 평진탕(平陳湯)의 비교연구)

  • Ji, Hyeon-Chyol;Baek, Tae-Hyeun
    • The Journal of Korean Medicine
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    • v.32 no.2
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    • pp.102-117
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    • 2011
  • Objectives: This study was performed to investigate the protective and treating efficacy of Pyeongwi-san, Ijin-tang, and Pyeongjin-tang extracts to the mice with gastric mucosal lesions induced from indomethacin. Methods: In order to verify protective and treating efficacy of Pyeongwi-san, Ijin-tang, and Pyeongjin-tang extracts to the mice with gastric mucosal lesions induced from indomethacin, I administered the extracts of these prescriptions to three group, and induced gastric mucosal lesion by indomethacin, and then I observed the gastric mucosal morphology of stomach, changes from stress resulting from HSP70, changes of gastro-protection (mucous barrier, COX-1). After I observed the anti-oxidant effect, and anti-inflammation effect (IKK mRNA, iNOS mRNA, COX-2 mRNA) in vitro, I induced gastric mucosal lesion by indomethacin, and administered the extracts of each prescriptions to three group, and then I observed the gastric mucosal morphology, anti-inflammation effect to mucosa (NF-${\kappa}$B, iNOS, COX-2) in vivo. Results & Conclusions: 1. Hemorrhagic erosion and damaged mucus secreting cell, positive responses to HSP70 were decreased in all the before-gastric-mucosal-lesion-induced groups, compared to non-extract administered group. The effects were good in the order of Pyeongwi-san extracts administered group, Pyeongjin-tang extracts administered group and Ijin-tang extracts administered group. 2. In all the before-gastric-mucosal-lesion-induced groups, gastro- protection functions (mucous barrier, COX-1) were significant. The effects were good in the order of Pyeongwi-san extracts administered group, Pyeongjin-tang extracts administered group and Ijin-tang extracts administered group. 3. Anti-oxidant effect was significant in Pyeongwi-san extracts, Ijin-tang extracts and Pyeongjin-tang extracts. The effects were good in the order of Pyeongjin-tang extracts, Pyeongwi-san extracts and Ijin-tang extracts. 4. The anti-inflammation effects in vitro were good in Pyeongwi-san extracts, Ijin-tang extracts and Pyeongjin-tang extracts. Especially Pyeongjin-tang extracts showed the most prominent results. Damaged mucus secreting cells and the positive reactions of NF-${\kappa}$B, iNOS, COX-2 in vivo were decreased in after-gastric-mucosal-lesion-induced groups compared to non-extract administered group. The effects were good in the order of Pyeongjin-tang extracts administered group, Pyeongwi-san extracts administered group and Ijin-tang extracts administered group. These results show that Pyeongwi-san, Ijin-tang and Pyeongjin-tang are effective on both in protecting and treating the gastric mucosal membrane. Pyeongwi-san is more effective than other prescriptions, in protecting gastric mucosal membrane, and Pyeongjin-tang is more effective in treating gastric mucosal lesion.

Study on the Ecological Restoration of Rock-exposed-cut-slope by Natural Topsoil Restoration Methods : In Case of Won-Ju Experiment (자연표토 복원공법에 의한 암절취비탈면의 생태적 복원에 관한 연구 : 원주사례지역을 중심으로)

  • Nam, Sang-Joon;Suk, Won-Jin;Kim, Nam-Choon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.2 no.4
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    • pp.54-63
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    • 1999
  • This study was conducted to suggest the ecological restoration and environmentally friendly revegetation technology for the rock-exposed cut-slopes by the Natural Topsoil Restoration Methods (NTRM) with the following restoration objectives; (1) prevention or reduction of wind and water erosion, (2) provision of food and cover for variety of animal species, (3) improvement of the visual or aesthetic quality of the disturbed slopes. On Nov. in 1995, the 5cm thick layer of artificial soil and 2cm thick layer of straw-mulching was attached at rock-exposed cut-slopes by NTRM without using anchor wire and anchor pin. The main results during four years surveying on the ground-coverage effect, plant growth, species diversity and importance values were summarized as follows. 1. Artificial soil attached at rock exposed cut-slopes was not eroded until recovered by tree and herbaceous vegetation in spite of not using anchor wire and anchor pin. Also it shows low soil hardiness and has almost the same amount of bacteria and fungi with in surrounding natural topsoil. 2. In 'combination for the woody vegetation', Lespedeza cyrtobotrya, Albizzia julibrissin, Rhus chinensis, Indigofera pseudo-tinctoria occupied upper layer vegetation. Since three years after seeding, Indigofera pseudo-tinctoria had overwhelmed the other woody plants and cool season foreign grasses, Erigeron canadensis, Taraxacum mongolicum, Commelina communis, Arundinella hirta (Thunberg) and Oenothera erythrosepala grows at lower part of the vegetation, 3. The heights of the Rhus chinensis grows 1.8m, Indigofera pseudo-tinctoria 2.0m, so it seems that the objectives of woody vegetation with native plants could be accomplished. 4. After 4 years later after seeding in 'combination for the herbaceous vegetation', the most dominant plant was Indigofera pseudo-tinctoria, the next was in order of cool-season grasses, Taraxacum mongolicum, Erigeron canadensis, lxeris dentata (Thunberg), Oenothera erythrosepala, Arundinella hirta (Thunberg). The diversity index in 'combination for woody vegetation' was higher than that in 'combination for the herbaceous vegetation'. The tendency of the intrusion of secondary succession plants was more effective in 'combination for the herbaceous vegetation' than in 'combination for the woody vegetation'.

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Sediment Properties and Long-term Bed Change of Munsancheon (문산천의 유사특성 및 장기하상변동 예측)

  • Lee, Jae-Geun;Ahn, Jae-Hyun
    • Journal of Wetlands Research
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    • v.13 no.2
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    • pp.329-341
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    • 2011
  • This study was conducted with the national river, Munsancheon, which is located in Paju-si, Gyeonggi-do. The sediment discharge of Munsancheon was directly measured to analyze the sediment characteristics, and the results were used in the numerical model to predict the long-term river bed variation. The flow-total sediment discharge relation was derived using the measured total sediment discharge, and the results were compared with the total sediment discharge that was calculated using the existing prediction formula to derive a proper sediment discharge prediction method. In the actual measurements, the total annual sediment discharge was 5,478 ton/year, and the specific sediment discharge was 29.23 ton/$km^2$/year. The Ackers & White formula resulted in the values very close to the actual measurements. With the actual sediment discharge, geographical and hydrologic data as the input variables, HEC-6 and GSTARS models were comparatively analyzed. The test results showed that the HEC-6 model is suitable for the reliable prediction of the long-term river bed variation. Accordingly, the model was used for the long-term river bed variation prediction in this study. In the case of Munsancheon, deposition was continued in the downstream area and erosion occurred in the upstream area on the whole. It was expected that the stream would be stabilized in the river bed condition of 20 years later. The river bed variation was within 1 m, which was at the significance level. In the downstream area that is influenced by tide, however, the accumulation was continuously increasing within the section 2,000-7,000 m from the outlet. It seems that this should be considered in establishing the river management plans.

Structural, Paleomagnetic and Petrological Studies of the Chugaryeong Rift Valley (추가령(標哥嶺) 지구대(地構帶)의 지질구조(地質構造), 고지자기(古地磁氣) 및 암석학적(岩石學的) 연구(硏究))

  • Kim, Kyu Han;Kim, Ok Joon;Min, Kyung Duck;Lee, Youn Soo
    • Economic and Environmental Geology
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    • v.17 no.3
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    • pp.215-230
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    • 1984
  • Petrological, paleomagnetic, geomorphological and structural studies on the southern part of, so called, Chugaryeong rift valley, have been carried out in order to clarify the nature of the rift valley. Three stages of volcanic activities characterized by Jijangbong acidic volcanic rocks and tholeiitic and andesitic basalt of Cretaceous age(?), and Jongok Quaternary olivine basalt occurred along the Dongducheon fault line. Jijangbong acidic volcanic rocks distributed in the central part of the studied area consist of rhyodacite, acidic tuff and tuff breccia, which are bounded by Dongsong fault on the east and Daegwangri fault on the west. The Jongok basalt differs from those of Ulrung and Jeju islands in mineralogy, chemical composition and differentiation. Jongok basalt distributed along the Hantan river dilineates the vesicles curved toward downstream direction and increment of numbers and thickness of lava flow toward upstream direction. These facts suggest that lava flowed from upstream side of the river. Rectangular drainage patterns also support the presence of the Dongducheon, Pocheon, Wangsukcheon and Kyonggang faults which were previously known. LANDSAT image, however, does not show any lineaments which could be counted as a graben or rift valley. Displacement of Precambrian quartzite and Jurassic Daedong supergroup along the southwestern extension of the Dongducheon fault shows the right lateral movement. The Paleomagnetic study of the tholeiitic and andesitic basalts from Baegeuri, Jangtanri and Tonghyeonri located at 2. 3km east, 0km east, and 1.5km west of Dongducheon fault respectively shows that their VGP(Virtual Geomagnetic Pole) being to intermediate geomagnetic field of short duration which suggests that they formed in almost same period. Mean VGP of Jongok basalt is located 82.4N and 80.6E. This is in good coincidence with worldwide VGP of Plio-Pleistocene indicating that Jongok basalt was extruded during Plio-Pleistocene epoch, and suggesting that the studied area has been tectonically stable since then. From the present study, the tectonic episode of the region is concluded as following three stages. 1. The 1st period is worked by the Daebo orogeny of Jurassic during which granodiorite was intruded in Precambrian basement. 2. The 2nd period is the time when right lateral strike-slip fault of NNE-SSW direction was formed probably during late Cretaceous to Paleogene and the Jijangbong acidic volcanic rocks and the older basalts were extruded. 3. The 3rd period is the time when the fault was rejuvenated during Pliocene or Pleistocene accompanied by the eruption of Jongok basalt. As a conclusion, geologic structure of the studied area is rather fault line valley than graben or rift valley, which is formed by differential erosion along the Dongducheon fault suggesting a continuation of the Sikhote-Alin fault. The volcanic rocks including the Jijangbong acidic rocks, tholeiitic-andesitic basalt and olivine basalt are associated with this fault line.

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Development and Evaluation of SWAT Topographic Feature Extraction Error(STOPFEE) Fix Module from Low Resolution DEM (저해상도 DEM 사용으로 인한 SWAT 지형 인자 추출 오류 개선 모듈 개발 및 평가)

  • Kim, Jong-gun;Park, Youn-shik;Kim, Nam-won;Chung, Il-moon;Jang, Won-seok;Park, Jun-ho;Moon, Jong-pil;Lim, Kyoung Jae
    • Journal of Korean Society on Water Environment
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    • v.24 no.4
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    • pp.488-498
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    • 2008
  • Soil and Water Assessment Tool (SWAT) model have been widely used in simulating hydrology and water quality analysis at watershed scale. The SWAT model extracts topographic feature using the Digital Elevation Model (DEM) for hydrology and pollutant generation and transportation within watershed. Use of various DEM cell size in the SWAT leads to different results in extracting topographic feature for each subwatershed. So, it is recommended that model users use very detailed spatial resolution DEM for accurate hydrology analysis and water quality simulation. However, use of high resolution DEM is sometimes difficult to obtain and not efficient because of computer processing capacity and model execution time. Thus, the SWAT Topographic Feature Extraction Error (STOPFEE) Fix module, which can extract topographic feature of high resolution DEM from low resolution and updates SWAT topographic feature automatically, was developed and evaluated in this study. The analysis of average slope vs. DEM cell size revealed that average slope of watershed increases with decrease in DEM cell size, finer resolution of DEM. This falsification of topographic feature with low resolution DEM affects soil erosion and sediment behaviors in the watershed. The annual average sediment for Soyanggang-dam watershed with DEM cell size of 20 m was compared with DEM cell size of 100 m. There was 83.8% difference in simulated sediment without STOPFEE module and 4.4% difference with STOPFEE module applied although the same model input data were used in SWAT run. For Imha-dam watershed, there was 43.4% differences without STOPFEE module and 0.3% difference with STOPFEE module. Thus, the STOPFEE topographic database for Soyanggang-dam watershed was applied for Chungju-dam watershed because its topographic features are similar to Soyanggang-dam watershed. Without the STOPFEE module, there was 98.7% difference in simulated sediment for Chungju-dam watershed for DEM cell size of both 20 m and 100 m. However there was 20.7% difference in simulated sediment with STOPFEE topographic database for Soyanggang-dam watershed. The application results of STOPFEE for three watersheds showed that the STOPFEE module developed in this study is an effective tool to extract topographic feature of high resolution DEM from low resolution DEM. With the STOPFEE module, low-capacity computer can be also used for accurate hydrology and sediment modeling for bigger size watershed with the SWAT. It is deemed that the STOPFEE module database needs to be extended for various watersheds in Korea for wide application and accurate SWAT runs with lower resolution DEM.

Analysis Gabion Works in Cut-slopes Characteristics and Scenic Preference (도로비탈면 돌망태공법의 특성 및 경관선호도 분석)

  • Park, Jae-Hyeon;Kim, Choonsig
    • Journal of Korean Society of Forest Science
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    • v.104 no.2
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    • pp.206-212
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    • 2015
  • This study was carried out to assess the characteristics of gabion on road cut-slopes, and analyze the scenic view preference for the gabion in Korea. 97 gabion sites from road cut-slopes were selected and were classified into 10 application types of gabion. The classification types of gabion were mostly related to the erosion and collapse prevention across road cut-slope. Gabion work sites in this study were classified into 30 sites (31%) for below 10% gradient, followed by 31 sites (32%) for 11~30% gradient, 20 sites (21%) for 31~50% gradient, and 16 sites (16%) for 51~80% gradient. Gabion works were constructed mostly in low gradient than in high gradient. 34 gabion sites (35%) among 97 sites were not covered by vegetation and 52 gabion sites (54%) showed vegetation cover rates of 1~30%. On the scenic preference analysis, public groups understood that the scenic view of gabion in cutting slope can be improved by vegetation cover, whereas expert groups prefer to scenic view of gabion only. However, expert groups encouraged subsequently vegetation covering to improve scenic view during gabion works in cutting slope.