• Title/Summary/Keyword: 김석철

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A Study on the Pollutant Dispersion over a Mountain Valley Region (I) : Wind Tunnel Experiments (산악 계곡지형에서의 오염확산에 관한 연구(I) :풍동실험)

  • Yoo Seong-Yeon;Shim Woo-Sup;Kim Seogcheol
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.11
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    • pp.1050-1059
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    • 2005
  • Heat and $SF_6$ gas dispersions over a complex terrain were investigated using wind tunnel. The wind speed, temperature and concentration profiles were measured for the 1/1000 scale complicated terrain model in an Eiffel type boundary layer wind tunnel with test section of 2.5m in height and 4.5m in width. The scale model was mounted on the top of a plate which can rotate with respect to the approaching wind. Dispersion processes from a continuous emission source driven by various wind direction were investigated, including plume climbing over the steep up-slope of the mountain and down-spreading toward the lower level of the valley. Extensive dispersion experiment data (wind speeds and concentration profiles) were provided for verification and validation of dispersion models. Under the identical flow and emission conditions, the independently measured profiles of the temperature and $SF_6$ concentration showed an excellent agreement which ensured the credibility of the results.

The Study on the Development of The Non-Gravity Fluidized Dryer (무중력 유동층 건조기 개발에 관한 연구)

  • Kim, Seok-Cheol;Bae, Dong-Kyu;Han, Ji-Woong;Kum, Sung-Min;Lee, Chang-Eon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.9
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    • pp.1195-1209
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    • 2000
  • The purpose of this study is to develop the non-gravity fluidized dryer. In this non-gravity fluidized dryer the fluidized zone is produced by two paddles in mixer, which maximizes the surface area of materials and then heated air through the guiding panels dehumidify them. This can conduct the drying process quickly and control moisture contents to lower limits. The ventilation system is closed loop system, which can be changeable to open system, and can be used as a multi-purposed dryer in which mixing, drying, granulating and cooling process is conducted. In order to develop the non-gravity fluidized dryer, in the first fundamental experiments were performed to mixing accuracy and then the other parts of dryer and control system were examined to check whether they were designed properly and operated harmoniously with mixer. Also the preparatory experiments were fulfilled to examine the efficiency and reliability of the dryer. Lastly, on the basis of preparatory experiments, performance test for the non-gravity fluidized dryer carried out for the variation of the initial moisture contents, desired moisture contents, heated air velocity and heating temperature.

Effects of Human Trampling Disturbance on the Vegetation at the Subalpine Zone near the Peak of Mt. Sorak, Korea (답압이 설악산 아고산대의 식생에 미치는 영향)

  • 이규송;최오길;김석철
    • The Korean Journal of Ecology
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    • v.25 no.5
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    • pp.321-328
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    • 2002
  • In order to provide the basic information for restoration of vegetation, conservation of rare species and maintenance of biodiversity, changes of site factors and vegetation by human trampling disturbance were investigated at the subalpine zone near the peak of Mt. Sorak in Korea. The destructed vegetation was found mainly in the southern parts with gentle slope in this study area. Height and coverage of vegetation and the species diversity decreased, and the community structure depended on trampling strength. Soil moisture, organic matter contents and litter thickness in the site with destructed vegetation by human trampling showed lower values than in the undisturbed site. Soil depth decreased, and gravel exposure on the ground surface increased by soil erosion responded to trampling strength.

Evaluation of One-particle Stochastic Lagrangian Models in Horizontally - homogeneous Neutrally - stratified Atmospheric Surface Layer (이상적인 중립 대기경계층에서 라그랑지안 단일입자 모델의 평가)

  • 김석철
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.4
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    • pp.397-414
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    • 2003
  • The performance of one-particle stochastic Lagrangian models for passive tracer dispersion are evaluated against measurements in horizontally-homogeneous neutrally-stratified atmospheric surface layer. State-of-the-technology models as well as classical Langevin models, all in class of well mixed models are numerically implemented for inter-model comparison study. Model results (far-downstream asymptotic behavior and vertical profiles of the time averaged concentrations, concentration fluxes, and concentration fluctuations) are compared with the reported measurements. The results are: 1) the far-downstream asymptotic trends of all models except Reynolds model agree well with Garger and Zhukov's measurements. 2) profiles of the average concentrations and vertical concentration fluxes by all models except Reynolds model show good agreement with Raupach and Legg's experimental data. Reynolds model produces horizontal concentration flux profiles most close to measurements, yet all other models fail severely. 3) With temporally correlated emissions, one-particle models seems to simulate fairly the concentration fluctuations induced by plume meandering, when the statistical random noises are removed from the calculated concentration fluctuations. Analytical expression for the statistical random noise of one-particle model is presented. This study finds no indication that recent models of most delicate theoretical background are superior to the simple Langevin model in accuracy and numerical performance at well.

Sorption Behavior of Cesium-137, Cerium-144 and Cobalt-60 on Zeolites (제오라이트에 대한 세슘-137, 세슘-144 및 코발트-60 흡착거동)

  • Kim, Seok-Chul;Lee, Byung-Hun
    • Journal of Radiation Protection and Research
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    • v.10 no.1
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    • pp.3-13
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    • 1985
  • The sorption behavior of some typical fission products such as Cs-137, long-lived radionuclide; Ce-144, rare-earth element; and Co-60, corrosion product on zeolite A, zeolite F-9 (faujasite) and amorphous zeolite was determined with the salt concentrations, 0.01 M- to 2.0 M- nitric acid and ammonium nitrate, and the shaking time, 15 minutes interval from 15 minute to 90 minute. Kd values were obtained through the batch experiment. In conclusion, the optimal conditions for isolation and removal of the typical radionuclides are as following: zeolite, amorphous zeolite; concentration, $0.01\;M-HNO_3\;and\;0.1\;M-NH_4NO_3$; pH4; shaking time, one hour; the most effective species, Cs-137.

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A Study on the Urban Heat Simulation Model Incorporating the Climate Changes (기후변화가 반영된 도시 열환경 시뮬레이션 모델의 연구)

  • Kang, Jonghwa;Kim, Wansoo;Yun, Jeongim;Lee, Joosung;Kim, Seogcheol
    • Journal of Korean Society for Atmospheric Environment
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    • v.34 no.5
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    • pp.697-707
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    • 2018
  • A fast running model comprising the climate change effects is proposed for urban heat environment simulations so as to be used in urban heat island studies and/or the urban planning practices. By combining Hot City Model, a high resolution urban temperature prediction model utilizing the Lagrangian particle tracing technique, and the numerical weather simulation data which are constructed up to year of 2100 under the climate change scenarios, an efficient model is constructed for simulating the future urban heat environments. It is applicable to whole city as well as to a small block area of an urban region, with the computation time being relatively short, requiring the practically manageable amount of the computational resources. The heat environments of the entire metropolitan Seoul area in South Korea are investigated with the aid of the model for the present time and for the future. The results showed that the urban temperature gradually increase up to a significant level in the future. The possible effects of green roofs on the buildings are also studied, and we observe that green roofs don't lower the urban temperature efficiently while making the temperature fields become more homogeneous.

Studies on the Ecological Management and Stream Environment in Dorim Stream for Establishing Eco-wetland Parks (도림천 수변지역 조성을 위한 생태적 관리방안 및 하천환경 관리방안에 관한 연구)

  • Lee, Sang-Don;Kim, Seok-Chul
    • Journal of Wetlands Research
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    • v.10 no.3
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    • pp.133-139
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    • 2008
  • Urban streams are degrading functional role due to development and pollution. This study chose the representative stream of Do-rim and identified flora and fauna. The ecological survey aimed at identifying indicator of urban streams for measuring urban healthiness and we discussed the possibility of wetland conservation area. From the beginning of Dorim stream to An-yang mixture we were successfully identified 113 species of plants, 9 of mammals, 23 of birds, 4 of amphibians, 2 of reptiles and 2 of fish species. Terrestrial insects were 71 species. The wetland vegetation is quite various and we suggested 4 different vegetation zones (aquatic vegetation zone, emergent zone, riparian-meadow zone, riparian-woodland zone) depending on distance from the flowing water stream and vegetation characteristics for urban stream management.

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하부 대류권에서 기상관측기기의 비교 관측을 위한 마산지역 기후변화 특성에 대한 고찰

  • Park, Jong-Gil;Jeong, U-Sik;Kim, Seok-Cheol;Kim, Sin-Ho
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 2007.05a
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    • pp.157-161
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    • 2007
  • 최근에 설치된 마산기상대의 windprofiler의 기기보정을 위한 비교관측을 하기에 앞서 마산기상대의 기상 관측자료를 이용하여 마산지역의 기후 변화 현황을 알아보았다. 그 결과, 마산지역은 최근 5년간 평년에 비하여 건조해졌으나 연강수량과 강수강도는 약한 증가현상을 나타내었다. 그리고 $20^{\circ}C$의 기온빈도가 증가하여 마산지역이 상당히 따뜻해 진 것으로 나타났다. 마산연보(2006)에 의하면 마산시에는 자동차 등록 수는 매년 증가하여 2005년 현재 138,241대를 나타내어 도시화로 인한 인공열원이 증가하였다고 볼 수 있다. 그렇지만 인구는 1998년 435,343명을 최고치로 나타낸 이후 매년 감소하는 추세를 보이고 있으며 사업체수 역시 1995년 35,622개 이후 점차 감소하고 있는 추세이다. 더불어 도심지 공원은 2005년 현재 91개까지 증가하였으며 공원 총면적 또한 2001년 이후 계속 증가하고 있는 추세이다. 마산지역의 기온이 $1985{\sim}2005$년 평년치보다 최근 5년간 상당히 따뜻해졌지만 자동차로 인한 인공열원의 증가가 인구 및 사업체 감소, 도심지 공원수와 면적 및 해풍 빈도의 증가와 상쇄되어 도시화의 영향이 다소 약하게 나타났으나 지구온난화와 더불어 마산지역의 기온도 상승하고 있음을 알 수 있다. 향후 지구온난화에 대한 영향을 지속적으로 조사할 필요가 있을 것으로 생각된다.

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Code Change for Using Large-Sized/High-Strength Headed Deformed Bars in Nuclear Power Plant Structures (대구경/고강도 확대머리철근의 원전구조물 사용을 위한 코드개정방안 연구)

  • Lee, Byung-Soo;Bang, Chang-Joon;Kim, Suck-Chul;Lim, Sang-Joon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.80-81
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    • 2014
  • Generally significant reinforcement is used for nuclear power plant structures and may cause potential problems when concrete is poured. In particular pouring concrete into structural member joint area is more difficult than other areas since the joint area is very congested due to hooked bars, embedded plates, and other reinforcements. The purpose of this study is to solve the problem by applying high-strength(ASTM A615 Gr. 75/80) bars. In addition large-sized(#14 & #18) headed deformed bar could be used as alternative of standard hooked bars to relieve the congestion to some extent. In order to apply headed deformed bars to nuclear power plant structures effectively, the large-sized diameter bars and the high-strength bars shall be used as thick as clear cover thickness 1". Therefore, test results were obtained by taking bar size, yield strength, and clear cover thickness as variables.

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A study on climate design using cold air flow to reduce air contaminant concentration of underground garage in the apartment complex (냉기류를 이용하여 공동주택단지 내 지하주차장 오염농도를 저감하는 기후 디자인에 관한 연구)

  • Kim, Tae Han;Cho, Kyung Hak;Chroi, Ji Hye;Kim, Seog cheol
    • KIEAE Journal
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    • v.11 no.1
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    • pp.29-38
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    • 2011
  • This study suggested practical application of climate design on apartment complex with the focus on the use of Cold Air Flow and green building design method. The domestic research on the wind path analysis has been associated since the early 21th century in urban planning and site planning, this initiative study aimed to mitigate the urban heat island effect and to promote the sustainable urban development. It is, however, mostly focused on the flow analysis and heat flow in the urban context, due to the poor application of the wind path analysis in actual planning and design. Special attention is paid to the possibilities of identifying and developing the application methods in relation to Cold Air Flow and building design. This study examined these relations and suggested some trenchant approach to a more comprehensive and efficient use of the wind flow analysis in climate design.