• Title/Summary/Keyword: Water exchange

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Numerical Simulation of Water-Exchange due to Overtopped Breakwaters (월파허용방파제에 의한 해수교환 수치모의)

  • Kim, In-Ho;Lee, Jung-Lyul
    • Journal of Ocean Engineering and Technology
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    • v.24 no.3
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    • pp.21-30
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    • 2010
  • This study presents a numerical simulation of sea water-exchange as a preliminary accessing tool of water quality in the protected shore behind a overtopped breakwater. The overtopped breakwater is taken into account for a safe swimming and beach protection. The overtopping rate is calculated by empirical models and the consequent currents, known as wave-induced currents, are calculated under the conditions of H.W.O.S.T and L.W.O.S.T. The rate of sea water exchange is used to evaluate the characteristics of sea water exchange and calculated through the simulation processes such as advective discharging through the outlets and random-walking diffusion of particles released within a basin. The numerical results show that the overtopped waves sufficiently improve the water exchange without healthless stagnation of contaminated mass and the consequent currents are not too strong for swimming.

Study on the Preparation of Polyvinyl Chloride Anion Exchange Membrane as a Separator in the Alkaline Water Electrolysis (알칼리 수전해용 격막으로서 폴리염화비닐(polyvinyl chloride) 음이온교환막의 제조에 관한 연구)

  • Park, Jong-Ho;Bong, Soo-Yeon;Ryu, Cheol-Hwi;Hwang, Gab-Jin
    • Membrane Journal
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    • v.23 no.6
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    • pp.469-474
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    • 2013
  • An anion exchange membrane was prepared for a separator in the alkaline water electrolysis. An anion exchange membrane was prepared by the chloromethylation and amination of polyvinyl chloride (PVC) used as a base polymer. The membrane properties of the prepared anion exchange membrane such as the membrane resistance and ion exchange capacity were measured. The minimum membrane resistance of the prepared anion exchange membrane was $2.9{\Omega}{\cdot}cm^2$ in 1M NaOH aq. solution. This membrane had 2.17 meq./g-dry-membrane and 43.4% for the ion exchange capacity and water content, respectively. The membrane properties of the prepared anion exchange membrane was compared with that of the commercial anion exchange membrane. The membrane resistance decreased in the order; AHT>IOMAC> Homemade membrane> AHA>APS=AFN. The ion exchange capacity decreased in the order; Homemade membrane>AFN>APS>AHT>AHA>IOMAC.

The Limiting Current Density and the Regeneration of a Heterogeneous Ion Exchange Membrane in a Nickel Plating Rinse Waters Treatment Process by Electrodialysis (전기투석에 의한 니켈도금 폐수처리 공정에서 한계전류밀도와 불균질 이온교환막의 재생)

  • 윤용수
    • Journal of environmental and Sanitary engineering
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    • v.16 no.2
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    • pp.38-46
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    • 2001
  • In this work, the heterogeneous ion exchange membrane was used in a electrodialysis apparatus to treat a Ni planting rinse water because the heterogeneous ion exchange membrane was excellent efficiency as compared with low manufacturing cost, was easy to make, and had a good mechanical properties. For a regeneration of membrane and to obtain the optimal condition for a scale-up of apparatus after treating Ni plating rinse water, we would find about the limiting current density and the concentration polarization. When the Ni plating rinse water 150mg/L was treated with the electrodialysis apparatus using the heterogeneous ion exchange membrane, the limiting current density was about $1.49{\;}mA/\textrm{cm}^2$. And the limiting current density increased with the flow rate and concentration of Ni plating rinse water. We recognized that the used membrane could be reused by periodic backwashing because efficiency was constant when the membrane was backwashed after treating wastewater.

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A Study on water-splitting characteristics of bipolar membranes for acid/base generation (산/염기 제조를 위한 바이폴라막의 물분해 특성 연구)

  • 강문성;문승현;이재석
    • Proceedings of the Membrane Society of Korea Conference
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    • 1998.10a
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    • pp.75-78
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    • 1998
  • 1. Introduction : The clean technology using ion exchange membranes have drawn attention increasingly with advancement of the membrane synthesis. Ion exchange membranes have been used for diffusion dialysis, electrodialysis, electrodialytic water splitting and electrodeionization. Bipolar membranes(BPM), consisting of a cation exchange layer and an an_ion exchange layer, can convert a salt to an acid and a base without chemical addition. Using the bipolar membrane, a large quantity of industrial wastes containing salts can be reprocessed to generate acids and bases. Recent development of high performance bipolar membranes enables to further expand the potential use of electrodialysis in the chemical industry. The water-splitting mechanism in the bipolar membrane, however, is a controversial subject yet. In this study bipolar membranes were prepared using commercial ion exchange membranes and hydrophilic polymer as a binder to investigate the effects of the interface hydrophilicity on water-splitting efficiency. In addition, the water splitting mechanism by a metal catalyst was discussed.

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Evaluation of NH4+-N Ion Exchange Property using Natural Zeolite and Zeolite Carrier (천연 제올라이트와 제올라이트 담체를 이용한 NH4+-N 이온교환 특성 평가)

  • Lee, Kwang Hyun;Park, Min Suk;Joo, Hyun Jong
    • Journal of Korean Society on Water Environment
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    • v.25 no.5
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    • pp.750-757
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    • 2009
  • The ammonium ion exchange characteristics of natural zeolite were investigated to remove ${NH_4}^+-N$. The effect of water temperature, particle size and competitive cation on the exchange capacity was examined. Ammonium ion exchange capacity tended to decrease when the temperature increased from $25^{\circ}C$ to $40^{\circ}C$. Exchange capacity was increased according to the particle size of natural zeolite comes to be small. Batch isotherm experiments were conducted for measuring ammonium ion exchange capacity. The ion exchange capacity was well described either by the Langmuir isotherm model or by the Freundlich isotherm model. The ammonium ion exchange capacity ($q_m$) of zeolite carrier can be calculated $11.744mg-{NH_4}^+/g$-carrier. The ion exchange capacity of manufactured zeolite carrier was showed a similar tendency as ion exchange capacity of powder-sized natural zeolite. Therefore, zeolite carrier can be used for increasing of nitrogen removal efficiency in the wastewater treatment plants.

Optimized Ballast Water Exchange Management for Bulk Carrier (BULK 선용자동 Ballast Water Management Plan 개발)

  • HONG CHUNG YOU;PARK JE WOONG
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.05a
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    • pp.67-72
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    • 2004
  • Many port states such as New Zealand, the USA, Australia and Canada have strict regulations to prevent ships which arrive in their port from discharging polluted ballast water which contain harmful aquatic organism and pathogens. They are notified that transfer of polluted ballast water can cause serious injury to public health and damage to property and environment. For this reason, they perceived that the ballast exchange in deep sea is the most effective method, together with submitting the ballast management plan which contains the effective exchange method, ballast system and safety consideration. In this study, we pursued both nautical engineering analysis and optimization of algorithm in order to generate the sequence of stability and rapidity. Heuristic Algorithm was chosen on the basis of optimality and applicability to a sequential exchange problem. We have built an optimized algorithm, for automatic exchange of ballast water, by redefining core elements of the $A^\ast$ algorithm, such as node, operator and evaluation function. Final version of the optimized algorithm has been applied to existing bulk carrier and the performance of the algorithm has been verified successfully.

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Optimized Ballast Water Exchange Management for Bulk Carriers (벌크 화물선용 자동 밸러스트수 교환계획 시스템 개발)

  • HONG CHUNG-YOU;PARK JE-WOONG
    • Journal of Ocean Engineering and Technology
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    • v.18 no.4 s.59
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    • pp.65-70
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    • 2004
  • Many port states, such as New Zealand, U.S.A., Australia, and Canada, have strict regulations to prevent arriving ships from discharging polluted ballast water that contains harmful aquatic organisms and pathogens. They are notified that transfer of polluted ballast water can cause serious injury to public health and damage to property and environment. For this reason, ballast exchange in deep sea is perceived as the most effective method of emptying ballast water. The ballast management plan contains the effective exchange method, ballast system, and safety considerations. In this study, we pursued both nautical engineering analysis and optimization of the algorithm, in order to generate the sequence of stability and rapidity. A heuristic algorithm was chosen on the basis of optimality and applicability to a sequential exchange problem. We have built an optimized algorithm for the automatic exchange of ballast water, by redefining core elements of the A$\ast$ algorithm, such as node, operator, and evaluation function. The final version of the optimized algorithm has been applied to existing bulk carrier, and the performance of the algorithm has been successfully verified.

Hydraulic Model Experiment on the Circulation in Sagami Bay, Japan (III) -The Time-Varying States of the Flow Pattern and Water Exchange in Barotropic Rotating Model-

  • Choo Hyo-Sang;Sugimoto Takasige
    • Fisheries and Aquatic Sciences
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    • v.1 no.2
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    • pp.260-268
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    • 1998
  • A flow pattern and water exchange in Sagami Bay is examined using a barotropic hydraulic model. In the model experiments, the volume transports of the Kuroshio Through Flow were changed with time. The results of the model experiments show that when the volume transport is increased with time, water mass and vorticity are transferred to the inner part of the bay by wakes from the western part of the bay. In the case of decrease, as the wakes are ceased, the inner cyclonic circulation water is discharged to the outside of the bay by its southward extension through the Oshima eastern channel. It is found that the water exchange by the short-term variation of volume transport in time is about 20% of all the bay water.

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Effects of the Oscillating Water Channel Length on the Water Surface Elevation within Seawater Exchange Breakwater (진동수로 내장 해수교환방파제의 수로길이 변화에 따른 수위공진)

  • Lee, Dal-Soo;Oh, Young-Min;Chun, In-Sik;Kim, Chang-Il
    • Ocean and Polar Research
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    • v.25 no.spc3
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    • pp.423-426
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    • 2003
  • The seawater exchange breakwater equipped with an oscillating water channel and water transmitting pipes has a very spectacular function that seawater supply can be greatly increased due to the upsurge of the water surface inside the channel at resonance condition which can be reached when the incident wave period becomes close to the natural period of the channel. The variations of the water level and period inside the channel are very important factors in enhancing the efficiency of sea water exchange, especially when designing the breakwater cross-section in shallow water zone which requires longer resonance period with the elongated horizontal projection of the channel. In the present study, a hydraulic experiment was performed varying the length of the oscillating channel, and the resonance periods and water surface variations are analyzed in terms of water transmission through the pipes.

The Calculation of Seawater Exchange Rate in a Port by Numerical Analysis (수치해석을 이용한 항만의 해수교환율 산정)

  • Kim, Hyung-Jun;Kang, Gyu-Young;Cho, Yong-Sik
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.237-240
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    • 2008
  • Numerical Analysis for exchanging seawater experiment is carried out in Do-Jang fish port. The change of tidal velocity and water level is derived by the two-dimensional nonlinear shallow-water numerical model. To calculate exchange rate of seawater with the change of tidal velocity and water level, a two-dimensional numerical model is employed which governing equations are Fokker-Plank equations. The calculated exchange rates of each time are described in tables and figures.

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