• Title/Summary/Keyword: flow filed

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A Case Study on Improvement of Field Training Coursework for Engineering Education - Comparison Korea with France (한국과 프랑스의 현장 실습 중심의 공학 교육 운영에 관한 사례 분석)

  • Kim, Hyeon-A;Hong, Chol-Ho;Kim, Byeong-Sam
    • Journal of Engineering Education Research
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    • v.10 no.2
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    • pp.5-18
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    • 2007
  • This paper presents a concept of training coursework for engineers in cooperation with the industry combining system, comparing Korea with France. The students, after first two years in a university for the foundation/basic courses, will be centered in the industry, rather than at an academic institution, where field training engineering coursework will be offered in structured or capstone design(problem based learning) formats through the industry. This study on the improvement of the concept has several advantages including the followings ; 1) Industry hiring local-area students who have the potential to be long-term employees; 2) Industry's immediate access to employees with developing engineering skills; 3) On-the-job training reduced industry training costs after graduation; 4) More effective learning through observing complex operations; 5) Students and industry input for continuous improvement of the curriculum; 6) Greater amenability on the part of industry to actively participate in research and development; 7) Increasing in the flow of real research problems for engineering. Finally, the implications for student quality, accreditation, assessment of partnership, academic freedom, and fundraising for scholarships and researches are discussed briefly.

Numerical Study of Stably Stratified Flow over a Three­dimensional Hill in a Channel (성층화된 수로에서 3차원 Hill에 의한 유속장 변동)

  • 박성은;김동선;이충일;황재동;윤종휘;조규대
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.9 no.2
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    • pp.73-77
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    • 2003
  • This study focuses on illustrating the effect of a hill on current filed at a channel, and the topographic effects of the hill were studied with various numerical experiments. The model experiments showed that stratification as well as bottom topography had influence on current fields around the hill. Due to stratification effect, Karman vortex formed behind the hill by bottom topography made effects on water movement only in the deep layer. The vortex reduced density field around the hill which resulted in the stratification in the water column, and which also resulted in the movement of isopycnic surface to deep layer both in front and back of the hill. The water in the back of the hill moved upward along ispycnic surface afterward. From these effects, velocity pattern in vertical direction around the hill showed opposite direction, downwrad in front of the hill and upward in the back. However, the upward flows did not seem to have any significant influence on the water conditions in the surface layer, even though strong upward flows were found on both side of the hill.

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Shear Behavioral Model based on Shear Deformation Compatibility in Reinforced Concrete Members (전단변형적합조건에 기반한 철근콘크리트 부재의 전단 해석 모델)

  • Kim, Woo;Rhee, Chang-Shin;Jeong, Jae-Pyong
    • Journal of the Korea Concrete Institute
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    • v.18 no.3 s.93
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    • pp.379-388
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    • 2006
  • This paper presents a model for evaluating the contribution by arch action to shear resistance in shear-critical reinforced concrete beams. Based on the relationship between shear and bending moment in beams subjected to combined shear and bending, the behavior of a beam is explicitly divided into two base components of the flexural action and the tied arch action. The compatibility condition of the shear deformation that deviates from Bernoulli bending plane is formulated utilizing the smeared truss idealization with an inclined compression chord. The Modified Compression Filed Theory is employed to calculate the shear deformation of the web, and the relative axial displacements of the compression and the tension chord by the shear flow are also calculated. From this shear compatibility condition in a beam, the shear contribution by the arch action is numerically decoupled. Then the validity of the model is examined by applying the model to some selected test beams in literatures. The results may confirm the rationale of the proposed behavioral model.

Two-Dimensional Hydrodynamic and Water Quality Simulations for a Coinjunctive System of Daecheong Reservoir and Its Downstream (대청호와 하류하천 연속시스템의 2차원 수리·모의)

  • Jung, Yong Rak;Chung, Se Woong;Ryu, In Gu;Choi, Jung Kyu
    • Journal of Korean Society on Water Environment
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    • v.24 no.5
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    • pp.581-591
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    • 2008
  • Most of our rivers are fragmented by the presence of at least one large dam. Dams are often the most substantial controller of the flow regimes and aquatic environments of natural river system. The quality of downstream water released from a stratified reservoir is highly dependent on upstream reservoir water quality. Thus, an integrated modeling approach is more efficient, compared to fragmented modeling approach, and necessary to better interpret the impact of dam operation on the down stream water quality. The objectives of this study were to develop an integrated reservoir-river modeling system for Daecheong Reservoir and its downstream using a two-dimensional laterally averaged hydrodynamic and water quality model, and evaluate the model's performance against field measurement data. The integrated model was calibrated and verified using filed data obtained in 2004 and 2006. The model showed satisfactory performance in predicting temporal variations of water stage, temperature, and suspended solid concentration. In addition, the reservoir-river model showed efficient computation time as it took only 3 hours for one year simulation using personal computer (1.88 Ghz, 1.00 GB RAM). The suggested modeling system can be effectively used for assisting integrated management of reservoir and river water quality.

A Study on the Application of Fire Modeling for Multiplex Cinema Theater (복합상영관 화재에 대한 화재모델링의 적용)

  • 허준호;김종훈;노삼규;김운형
    • Fire Science and Engineering
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    • v.18 no.1
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    • pp.42-48
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    • 2004
  • The deterministic modeling techniques like Zone model and Field model are mainly used for thermal distribution and smoke flow at fire case in multi use facilities. While Zone model analyse fire simulation by dividing spaces by 2 section, the Field model dividing many cells. However, the difficultly follows to prove efficiency between the two models when it applys. Therefore new modeling development is required which in closes to real situation by verify number algorithm and related data for fire modeling. The paper analyses the efficiency of two different fire modeling at interior spaces of multiplex cinema theater. It is found that the zone model for average distribution and the field model for detail space phenomenon are relevant to apply. Also, Filed model is useful to the result that fire analysis and position of detector and review for smoke control system.

MR Angiography with Simultaneous Data Acquisition of Arteries and Veins(SAAV) Method and Artery-Vein Color Mapping in 0.3T MRI System (0.3T MRI 시스템에서의 동.정맥 동시 획득을 위한 자기공명 혈류 영상 기법(SAAV)과 동.정맥 color mapping)

  • 조종운;조지연;서성만;은충기;문치웅
    • Journal of Biomedical Engineering Research
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    • v.24 no.4
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    • pp.275-280
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    • 2003
  • The method of simultaneous data acquisition of arteries and veins(SAAV) was suggested to obtain MR angiography of arteries and veins at 0.3T low filed MRI system (Magfinder, AlLab. Korea). Two separated artery- and vein-images were put together using AVCM(Artery-Vein Color Mapping) algorithm and presented in the same image. In this study, artery- and vein-separated angiograms of volunteer's neck were obtained. Two dimensioal blood-enhanced images wre sequentially obtained using SAAV pulse sequence based on time-of-flight(TOF) method with flow compensation. Imaging parameters were TR/TE=70/12msec. FOV=230mm, slice thickness = 3mm, flip angle=90$^{\circ}$, matrix size=256${\times}$256${\times}$64mm. TSat TH/SPA=15/20mm, Ts_v=10msec and Ts_a=40ms. 3D MRA images were reconstructed using the maximum intensity projection(MIP) and the artery-vein color mapping(AVCM) algorithm. This study showed good possibility of clinical applications of MRA in 0.3T which provides valuable diagnostic information of clinical vascular diseases.

Heat Transfer by Heat Generation in Electrochemical Reaction of PEMFC (고분자 전해질 연료전지에서 전기화학반응 열생성에 의한 열전달특성)

  • Han, Sang-Seok;Lee, Pil-Hyong;Lee, Jae-Young;Park, Chang-Soo;Hwang, Sang-Soon
    • Journal of the Korean Electrochemical Society
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    • v.11 no.4
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    • pp.273-283
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    • 2008
  • GDL(Gas Diffusion Layer) is one of the main components of PEM fuel cell. It transports reactants from the channel to the catalyst and removes reaction products from the catalyst to the channels in the flow filed plate. It is known that higher permeability of GDL can make it possible to enhance the gas transport through GDL, leading to better performance. And MEA's temperature is determined by gas and heat transport. In this paper, three dimensional numerical simulation of PEM fuel cell of parallel channel and serpentine channel by the permeability of GDL is presented to analysis heat and mass transfer characteristics using a FLUENT modified to include the electrochemical behavior. Results show that in the case of parallel channel, performance variation with change of permeability of GDL was not so much. This is thought because mass transfer is carried out by diffusion mechanism in parallel channel. Also, in the case of serpentine channel, higher GDL permeability resulted in better performance of PEM fuel cell because of convection flow though GDL. And mass transfer process is changed from convection to diffusion when the permeability becomes low.

A Study on Efficiency of Water Purification of Korean Village Bangjuk[dike] as a Means of Ecological Watershed Management (생태적 유역관리 도구로써 마을방죽의 수질정화 효율성 고찰)

  • An, Byung-Chul
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.30 no.2
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    • pp.90-100
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    • 2012
  • This study centering on 10 village - Bangjuks analyzed multifunctionality value of village Bangjuks which have been main water treatment system in Korean traditional villages. On the basis of understanding the structure and character of components such as the well, common spring, village waterway and others which making water-flow and consisting of aquatic system in Korean traditional village Bangjuk, the conclusion as the instrumental device of social and ecological role and ecological watershed management, securing the ecosystem soundness of the damaged or deteriated aquatic ecosystem due to the industrialization and urbanization is as below; 1. The traditional village Bangjuk was environmentally friendly hydraulic system which gathers waterways of village into a point including sewage water, retains and flows out to village through agricultural waterway. Through this Bangjuk, they have managed sewage and rainfall runoff flowed out village efficiently. It is not only a detention system of water but a kind of eco-friendly system that flow out water into the rivers after reusing and filtering it. 2. Around five traditional villages and five villages after modernization, this study classified the types of village Bangjuk as three types considering geographic location, size, etc; marsh type of low swamp, high water -low rice field type of natural flow stucture, low water - high rice field type requiring artificial irrigation facility. All the five traditional villages were turned out to be marsh type of low swamp. Geoji, Sanjeri, Ma-am, Yangchon of the agricultural villages were high water-low rice filed type, and Sangchoenri village was classified low water-high rice field type. 3. This study checked up the function of water purification of village Bangjuk. In Wonteo and Geji villages affected by discharge of village sewer and domestic sewage, the efficiency of ammonia nitrogen($NH_3-N$) and total phosphorus(T-P) was 56~95%, which was high. In Sangcheonri and Sanjeri villages strongly affected by stall and farmland, the efficiency of suspended solids(SS) was 70~85%, and that of total nitrogen(T-N) and total phosphorus(T-P) was 5.3~65%. 4. A water purification system can be found out in the system of village Bangjuk that filter out village sewage and rainfall runoff flowed through the settle and filter of pollution source and denitrification of plants. Through this system of village Bangjuk, it must be used as the basic facilities for the ecological watershed management. The sewage management system of village Bangjuk as a eco-filter must be used and studied as an eco-friendly facility for the ecological watershed management around the subwatershed and catchment.

Development and Field Test of a Smart-home Gas Safety Management System (스마트 홈 가스안전관리 시스템 개발 및 현장시험)

  • Park, Gyou-Tae;Kim, Eun-Jung;Kim, In-Chan;Kim, Hie-Sik
    • Journal of the Korean Institute of Gas
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    • v.16 no.6
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    • pp.128-135
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    • 2012
  • In this paper, we proposed a system and a scenario to raise efficiency of gas safety management by developing wireless ZigBee communication modules, smart-home gas safety appliances and the system suitable for gas safety. Our designed system consists of a micom gas meter, an automatic extinguisher, sensors, and a wall-pad. A micom-gas-meter monitors gas flow, gas pressure, and earthquake. An automatic fire extinguisher checks combustible gas leaks and temperature of $100^{\circ}C$(cut off) and $130^{\circ}C$(fire). Sensors measure smoke and CO gas. In our novel system, a micom-gas meter cut off inner valve with warnings, an automatic fire extinguisher cut off middle valve and spray extinguishing materials, and sensors generate signals when detecting smoke and CO and then take a next action. Gas safety appliances and sensors automatically takes measures, and transmit those information to a wall-pad. The wall-pad again transmits real time information to server. Users can check and manage gas safety situations by connecting BcN server through web or mobile application. We hereby devised scenarios for gas safety and risk management based on the smart, and demonstrated their efficiency through test applied to filed.

The Coastal Geomorphic System of Sagye, Jeju (제주 사계해안의 지형시스템)

  • Seo, Jong-Cheol;Son, Myoung-Won
    • Journal of the Korean association of regional geographers
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    • v.13 no.1
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    • pp.32-42
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    • 2007
  • In Sagye coast of Andeok-myeon, southwestern Jeju, shore platform of noncohesive Hamori Formation, marine terrace deposit of round gravels, coastal dune composed of shell sand and volcanic sand, and back lake are linked closely with each other. In this paper, the formation process of Sagye coastal geomorphic system analysed by using OSL dating method is as follows: Firstly, Hamori Formation is a horizontal stratum filed up of tuff reworked by submarine volcanic eruption during 3$\sim$7.6 ka BP. Hollow at the boundary between Hamori Formation' flat and Kwangheak Basalt's gentle slope become a back lake when block is appeared over the sea level by uplift. Secondly, while Hamori Formation was laid below sea level, gravels which had been broken and abraded at southwestern rocky coast composed of Kwangheak basalt or been transported through the small stream from adjacent hillslope were deposited in rapid flow environment. Thirdly, deposition of round gravels was ceased by earth uplift, and shore platform was constructed by abrasion process of energy of swash moving forward. As altitude of shore platform is equal to high tidal level of spring tide, compared it with present high tidal level of study area, earth is uplifted about 105m since shore platform was formed. Fourthly, much sandy sediments transported from offshore bottom covered shore platforms and marine terrace deposits. Lighter sediments among sandy sediments was blown to back, formed secondary sand dune since about 500 year.

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