• Title/Summary/Keyword: 침투능력

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Analysis of the effects of the seawater intrusion countermeasures considering future sea level rise in Yeosu region using SEAWAT (SEAWAT을 이용한 미래 해수면 상승에 따른 여수지역 해수침투 저감 대책 효과 분석)

  • Yang, Jeong-Seok;Lee, Jae-Beom;Kim, Il-Hwan
    • Journal of Korea Water Resources Association
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    • v.51 no.6
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    • pp.515-521
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    • 2018
  • Seawater intrusion areas were calculated in Yeosu region considering sea level rise and the effects of countermeasures for seawater intrusion were analyzed using SEAWAT program. The estimated seawater intrusion area was $14.90km^2$ in 2015. When we applied climate change scenarios the area was changed to $19.19km^2$ for RCP 4.5 and $20.43km^2$ for RCP 8.5 respectively. The mitigation effects by artificial recharge with total $50m^3/d$, $100m^3/d$, and $300m^3/d$ are from 3.75% to 10.68% for RCP 4.5, and from 5.82% to 10.77% for RCP 8.5 respectively. If we install barrier wall with the thickness 0.8 m, 1.3 m, and 1.8 m, the mitigation effects are from 6.67% to 12.04% for RCP 4.5, and from 6.17% to 14.98% for RCP 8.5 respectively. The results of this study can be used to be a logical means of quantitative grounds for policy decisions to prevent groundwater contamination by seawater intrusion and subsequent secondary damage in coastal areas.

A Study on the Rainfall Infiltration Capacity of Soil (A Study on the Mid-Mountain Area of Jeju Island) (강우의 토양 침투 투수성 연구(제주도 중산간 지역을 중심으로))

  • Jeon, Byeong Chu;Lee, Su Gon;Kim, Sung Soo;Kim, Ki Su;Kim, Nam Ju
    • The Journal of Engineering Geology
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    • v.29 no.2
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    • pp.99-112
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    • 2019
  • Rainfall infiltration through the unsaturated zone is influenced by a range of factors including topography, geology, soil, rainfall intensity, temperature and vegetation; the actual infiltration varies largely in time and space. The infiltration capacity of soil is a critical factor in identifying groundwater recharge and leakage of surface water. It may differ depending on soil types and geological features of a particular basin or territory as well as on the usage of the land. This study was conducted in forest and farmland region of the mid-mountain area (EL. 50~300 m) of Jeju Island to test soil infiltration capacity of the area where rainfall contributes to groundwater. Results were analyzed using the four soil group classification methods presented by Jeong et al. (1995) and NAS (2007) to discover that the method offered by NAS (2007) is more reliable in the mid-mountain area of Jeju Island. The study compares and reviews the existing classification methods using the results of infiltration capacity tests executed on different soil groups throughout the whole region of the Jeju mid-mountain area. It is expected that this work will serve as a guideline for evaluating surface water recharge and hydraulic characteristics of Jeju Island.

Service Life Prediction of R.C. Structures Considering Chloride Binding (염화물 고정화를 고려한 철근 콘크리트 구조물의 내구수명 예측)

  • Lee, Chang-Soo;Park, Jong-Hyok;Kim, Young-Ook
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.1
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    • pp.15-22
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    • 2010
  • Chloride-induced corrosion of steel bars in concrete exposed to marine environments has become one of the major causes of deterioration in many important facilities made of reinforced concrete. A study on chloride penetration in concrete has developed through long period exposure test along seawater, assesment of chloride ion diffusion by electrochemical techniques and so on. However, reasonable and exclusive chloride penetration model considering concrete material properties with mixture, degree of hydration, binding capacity has not been established. Therefore, in this paper, chloride penetration analysis of non-steady state is accomplished with material properties of concrete. Comparing with the results of analysis and chloride ponding test, we could accept the effect of binding capacity on chloride penetration in concrete and these results could be applied to a service life prediction of R.C. structures submerged in seawater. Therefore, there are 20~40% differences of service life to SHRP prediction.

Evaluation of the Efficiency of Crushed-Stone Detention Pond considering Rainfall Characteristics (강우의 특성을 고려한 쇄석저류지의 효율성 평가)

  • Kim, Kee-Wook;Kim, Kyoung-Jun;Park, Chang-Yeol;Yoon, Jung-Su;Yoo, Chul-Sang
    • Proceedings of the Korea Water Resources Association Conference
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    • 2008.05a
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    • pp.1285-1289
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    • 2008
  • 최근 도시지역의 확대와 고밀도화에 따른 도시근교의 산림, 논밭, 녹지 등이 감소하고, 도로나 건축물 등의 증가로 인해 불투수 유역이 확대되어, 원래 그 토지가 유지하고 있던 보수 유수 기능이 현저히 저하되고 있다. 그 결과 강우 시 표면 유출량의 증가와 유출시간의 단축이 현저하게 되고, 도시하천이나 하수도 유하 능력을 넘는 홍수가 자주 발생하고 있다. 또한 빗물 침투량이 줄어들어, 용천수 고갈, 하천의 평상시 유량감소가 나타나게 된다. 이러한 문제를 해결하기 위해 최근 유역 내에 저류시설과 침투시설 등 유출저감효과를 기대할 수 있는 여러 가지 시설의 활용방안이 꾸준히 모색되고 있다. 본 연구에서는 이러한 내배수 홍수분담시설 중 저류와 침투의 기능을 모두 갖추고 있는 쇄석공극저류시설의 효율성을 분석하였다. 또한 쇄석저류지와 규모와 형태가 유사한 우수저류지와의 비교를 통해 상대적인 효율성을 평가하였다. 그 결과 두 시설이 같은 규모를 가진다고 가정할 때, 우수저류지가 쇄석저류지에 비하여 월등한 유출저감효과를 보이는 것으로 파악되었다.

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Review of the study on the surfactant-induced foliar uptake of pesticide (계면활성제에 의해 유도되는 농약의 엽면 침투성 연구 현황)

  • Yu, Ju-Hyun;Cho, Kwang-Yun;Kim, Jeong-Han
    • The Korean Journal of Pesticide Science
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    • v.6 no.1
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    • pp.16-24
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    • 2002
  • Research trends in the measurement of foliar uptake of pesticides and the recently proposed action mechanism of the surfactant-induced uptake of pesticides were reviewed with the related reports and studies. Major techniques used in those fields are bioassay, radiotracer techniques with leaves or cuticular membrane. Recently, a new method using Congo Red as a tracer was proposed. The limiting factor in the pesticides uptake into leaves is the waxy layer which consists of the epicuticular and cuticular wax. Physico-chemical parameters such as molar volume, water solubility and partition coefficient of pesticides have limited influences on the pesticide uptake into leaves. Polydisperse ethoxylated fatty alcohol surfactants are well known as the good activator for many pesticides. It is now generally agreed that uptake activation is not related to the intrinsic surface active properties of surfactants such as surface activity, solvent property, humectancy and critical micelle concentration. Recent studies using ESR-spectroscopy revealed that the surfactants have an unspecific plasticising effect on the molecular structure of the wax and cuticular matrix, leading to increased mobilities of pesticides. Penetration of surfactants into waxy layer altered the pesticide mobility in wax and the partition coefficient of pesticide, and then the pesticides penetration into leaves was enhanced temporally. The enhancing effect of surfactant could be significantly different depending on the carbon number of aliphatic moiety and the number of ethoxy group in polyoxyethylene chain of surfactants. It is suggested that the rate of penetration of surfactants should have a significant relationship with the rate of penetration of pesticides.

Analysis of Fire Suppression Efficiency for Intermittent Water Spray Pattern by Fire Dynamics Simulator (FDS를 이용한 교번식 미분무방식의 소화 성능 분석)

  • Jee, Moon-Hak;Lee, Byung-Kon
    • Fire Science and Engineering
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    • v.22 no.3
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    • pp.216-220
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    • 2008
  • Water mist fire suppression system utilizes the fire suppression features such as cooling of fire source, dilution of ambient oxygen, and shielding of radiation heat with the evaporation of microscopic water droplets. The momentum of water mist is relatively lower than that of larger water droplet and the infiltration of water mist to the fire source is not effective. Contribution of evaporated water vapor is liable to decline to limited portion of fire source due to its light weight and sparse density. On the other hand, the cycling water mist pattern is expected to improve the penetration force of water mist as well as the air expelling capability with the stratified spray characteristics. At this paper, we present the analyzed fire suppression capability of intermittent water spray pattern by use of FDS which is computational fire dynamics fire model. We expect this analysis can support the basic concept to the development of the prototype of water mist nozzle.

열정! 건설현장을 찾아서 - 안전으로 재난에 강한 도시 기반 건설, 태영건설, 아산탕정지구 분산형 빗물관리 도시조성공사현장

  • Yeon, Seul-Gi
    • The Safety technology
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    • no.181
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    • pp.16-18
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    • 2013
  • 충남 천안시에 최근 새로운 변화의 바람이 불고 있다. 친환경적이며 홍수 등 자연 재해에 효과적으로 대응할 수 있는 '분산형 빗물관리 도시조성공사'가 국내 최초로 펼쳐지고 있는 것이다. 일반적으로 도시 및 택지 개발을 하면 자연재해 대응능력이 떨어지는 것으로 알려져 있다. 예를 들어 비가 올 때 콘크리트 등으로 덮인 땅은 빗물이 잘 침투되지 않는다. 때문에 순간적으로 하천으로 많은 양의 물이 흘러서 홍수의 위험이 커진다. 하지만 천안시에서 현재 진행 중인 '분산형 빗물관리 도시조성공사'는 오염원을 처리하는 가운데 빗물의 하천 방류와 땅 속 침투를 개발 전처럼 가능하게 한다. 또 일부는 땅속에 저장시켜 일시적인 수랑 증가로 인한 홍수를 예방한다. 오는 2016년 6월에 이 사업이 완료되면 천안 서북부 일대는 상당한 침수예방 효과를 얻게 된다. 더불어 위생적인 도시환경이 조성되는 것은 물론 주민생활 환경도 크게 개선된다. 실로 재난과 재해에 강한 미래 천안의 모습이 미리 그려지고 있는 것이다. 때문에 이곳 공사를 맡고 있는 태영건설의 자긍심은 남다르다. 모든 현장 임직원들이 빈틈없는 안전관리로 최고의 도시 기반을 만들겠다는 의지를 불태우고 있다. 안전으로 재난에 강한 미래 도시를 만들어가고 있는 이곳 현장을 찾아가 봤다.

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The Physical Properties Variation of Grout Materials and Improvement of Grouting Effects on Application of High Performance Injection Equipment (고성능 주입장비의 적용에 따른 주입재의 물성변화 및 주입효과 증진에 관한 연구)

  • 천병식;김진춘;김백영
    • Journal of the Korean Geotechnical Society
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    • v.19 no.4
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    • pp.179-190
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    • 2003
  • The grout based on solution type makes it difficult to get the improvement of ground strength and the effefct of water curtain because it has lower strength and durability than suspension type. Nowadays, the technology of particle acceleration, that enhance the material permeability, such as grout based on solution type, and inexpensive grout, is being required. For these reasons, in this study, using wet milling system, we evaluated physical properties of manufactured factors such as water-cement ratio of particles before being milled, optimum milling capacity by controlling milling time and rpm, viscosity of materials, permeation coefficient, and unconfined compressive strength. Also, using micro wet milling apparatus which could manufacture ordinary Portland cement and high speed shear mix which could forcefully separate conglomerate particles in situ, we performed electrical resistivity investigation and falling head permeability tests to analyze differences of grouting effects. From these results, we found that the permeability of the applied equipment was much superior, and in the case of using high speed shear mixer, particles of grout material were well separated.

THE ANTICARIOGENIC EFFECT OF RESIN INFILTRATION ACCORDING TO THE PRETREATMENT OF SURFACE LAYERS IN NATURAL INCIPIENT CARIES LESIONS (초기 우식 병소의 표층 처리에 따른 Resin infiltration의 우식 저지 능력 평가)

  • Kim, Min-Jeong;Lee, Dong-Soo;Kim, Shin;Jeong, Tae-Sung
    • Journal of the korean academy of Pediatric Dentistry
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    • v.37 no.4
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    • pp.412-421
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    • 2010
  • As a most conservative, minimally invasive trial against early caries lesions, resin infiltration concept has been introduced and studied mainly about effective materials and pre-treatment methods of surface layers to arrest the lesion effectively, which is still going on. This study was performed with an aim of evaluating the efficacy of arresting the caries process in the natural incipient lesions in spite of removing the surface layers and we obtained the results as follows: 1. It was revealed that infiltration groups(1, 3, 5) showed lower radio-density decline between pre- and posttreatment than control groups(2, 4, 6)(p<0.05). 2. Group 5, in which the surface layer was removed with hydrochloric acid, showed the most significant anticariogenic effect(p<0.05). 3. Under SEM evaluation after infiltration, group 1 and 3 showed more irregular destruction and intensive loss of surface layers than group 5. In conclusion, it was thought resin infiltration can be an effective tool against the early caries lesions although surface layers are removed.

Effect of Adding Taurine, Hypotaurine and Trehalose as Antioxidants to a Tris-based Egg Yolk Extender on Korean Jeju Black Bull Sperm Quality Following Cryopreservation (제주흑우 동결정액 제조에 있어 난황 Tris 희석제에 항산화제로서 Taurine, Hypotaurine 그리고 Trehalose의 첨가가 동결 융해 후 정자의 성상에 미치는 영향)

  • Oh, Shin-Ae;Ko, Min-Hee;Kang, Tae-Young;Choi, Sun-Ho;Ko, Moon-Suck;Chung, Young-Ho;Cho, Won-Mo
    • Journal of Animal Science and Technology
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    • v.54 no.4
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    • pp.283-290
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    • 2012
  • Cryopreservation induces sublethal damage to the spermatozoa, which leads to their reduced fertile life. The objective of this study was to investigate the effect of taurine, hypotaurine and trehalose as antioxidants on the function of the freezing-thawed sperm in Korean Jeju Black Bull. The semen was cryopreserved with tris egg yolk extendercontaining 7% glycerol and treated with 20mM taurine, hypotaurine and trehalose. Frozen-thawed sperms were evaluated for sperm motility, viability, membrane integrity, acrosome integrity and sperm penetration ability. The results were compared to semen cryopreserved in tris egg yolk extender containing 7% glycerol only as control. Frozen-thawed semen evaluation clearlyindicated that the addition of taurine or hypotaurine significantly improved (p<0.05) the motility and viability compared to control spermatozoa. Moreover, in membrane integrity, swollen sperm ratio was significantly increased (p<0.05) in taurine, hypotaurine or trehalose compared to control. In sperm acrosome integrity, F pattern ratio was increased (p<0.05) in hypotaurine among treatments, and AR pattern was significantly lowered (p<0.05) in taurine, hypotaurine and trehalose. In assessed sperm fertilizing ability, taurine, hypotaurine or trehalose significantly improved (p<0.05) the ratio of pronucleus formation and SFI. Finally, compared with the control, addition of taurine, hypotaurine or trehalose as an antioxidant to the freezing extender showed more positive effects on the frozen-thawed spermatozoa. It is concluded that the addition of taurine, hypotaurine, or trehalose to the freezing extender could reduce cryodamage of the Korean Jeju Black Bull spermatozoa.