• Title/Summary/Keyword: Land load

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Estimating Method of Topographic Factor of Design Wind Speed Using GIS (GIS를 이용한 지형에 의한 풍속할증계수 산정 방법)

  • Choi, Se-Hyu;Seo, Eun-Su
    • Journal of the Korean Association of Geographic Information Studies
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    • v.16 no.3
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    • pp.126-135
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    • 2013
  • With more than 70% of the country consisting of mountains, Korea has large and small mountains, and hills located in the inner cities. Therefore, Korea's architectural structure laws stipulate that an increase in wind speed due to the influence of terrain should be considered in the design of wind loads of buildings. But if more than two mountains are located around the building or if the boundaries of the land surface are not clear when calculating topographic factors of wind speed, the designer has subjectively selected the coverage of the topographic factors of wind speed or the surface. This may lead to unscientific design of wind loads. This study attempts to analyze topographic factors of wind speed by using a 1:5000 topographic map with relatively high location accuracy and thereby to reflect changes due to the topographic characteristics and influence at the point where the building is located. By also selecting terrain surfaces and vertexes through Arc GIS and presenting a scientific approach to determine the range of topographic factors of wind speed, this study is expected to make a contribution for more rational and cost-effective wind-resistant design of buildings.

Investigation of Institutional Improvement through Evaluation of Zero-Energy Buildings (제로에너지 빌딩 평가를 통한 제도적 개선방안에 대한 조사 연구)

  • Chae, Sookwon;Kim, Juhwan;Chae, Hyunbyung
    • Journal of Energy Engineering
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    • v.25 no.3
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    • pp.83-94
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    • 2016
  • Energy use has been recognized worldwide as a main cause of global warming and it is at the center of climate change. In this study, problems and measures of zero-energy building construction are investigated and analyzed. Based on the results, evaluation criteria of the zero-energy building are suggested. Performance related factors(Q) representing the environmental grade were divided into three categories as outdoor, indoor environment and maintenance. Energy related factors(LR) representing the energy load were divided into an energy, materials & resources, water cycle management, land use and transportation. Detailed fifty three items are listed for the evaluation under the consideration of energy, water cycle management sections gave weight. Upon receiving the first in the environment friendly certification system, Seoul Central Post Office and Seoul Metropolitan Water Supply Center evaluated. The reason why this score difference is due to lack of use of new generation energy building construction is required expensive costs so need expansion of governmental support. This effort is successful zero energy building construction and copes with global warming and climate change.

A Study on BASINS/WinHSPF for Evaluation of Non-point Source Reduction Efficiency in the Upstream of Nam-Han River Watershed (BASINS/WinHSPF를 이용한 남한강 상류 유역의 비점오염원 저감효율평가)

  • Yoon, Chun-Gyeong;Shin, Ah-Hyun;Jung, Kwang-Wook;Jang, Jae-Ho
    • Journal of Korean Society on Water Environment
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    • v.23 no.6
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    • pp.951-960
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    • 2007
  • Window interface to Hydrological Simulation Program-FORTRAN (WinHSPF) developed by the United States Environmental Protection Agency (EPA) was applied to the upstream of Nam-Han river watershed to examine its applicability for loading estimates in watershed scale and to evaluate non-point source control scenarios using BMPRAC in WinHSPF. The WinHSPF model was calibrated and verified for water flow using Ministry of Construction and Transportation (MOCT, 3 stations, 2003~2005) and water qualities using Ministry of Environment (MOE, 5 station, 2000~2006). Water flow and water quality simulation results were also satisfactory over the total simulation period. But outliers were occurred in the time series data of TN and TP at some regions and periods. Therefore, it required more profit calibration process for more various parameters. As a result, all the study was performed within the expectation considering the complexity of the watershed, pollutant sources and land uses intermixed in the watershed. The estimated pollutant load for annual average about $BOD_5$, T-N and T-P respectively. Nonpoint source loading had a great portion of total pollutant loading, about 86.5~95.2%. In WinHSPF, BMPRAC was applied to evaluate non-point source control scenarios (constructed wetland, wet detention ponds and infiltration basins). All the scenarios showed efficiency of non-point source removal. Overall, the HSPF model is adequate for simulating watersheds characteristics, and its application is recommended for watershed management and evaluation of best management practices.

Impact of Climate Change on Water Cycle and Soil Loss in Daecheong Reservoir Watershed (기후변화에 따른 대청호 유역의 물 순환 및 토양 유실량 영향)

  • Ye, Lyeong;Chung, Se Woong;Oh, Dong Geun;Yoon, Sung Wan
    • Journal of Korean Society on Water Environment
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    • v.25 no.6
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    • pp.821-831
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    • 2009
  • The study was aimed to assess the expected impact of climate change on the water cycle and soil losses in Daecheong Reservoir watershed, Korea using the Soil and Water Assessment Tool (SWAT) that was validated for the watershed in a previous study. Future climate data including precipitation, temperature and humidity generated by introducing a regional climate model (Mesoscale Model Version 5, MM5) to dynamically downscale global circulation model (European Centre Hamburg Model Version 4, ECHAM4) were used to simulate the hydrological responses and soil erosion processes in the future 100 years (2001~2100) under the Special Report on Emissions Scenario (SRES) A1B. The results indicated that the climate change may increase in the amount of surface runoff and thereby sediment load to the reservoir. Spatially, the impact was relatively more significant in the subbasin Bocheongcheon because of its lower occupation rate of forest land compared to other subbasins. Seasonally, the increase of surface runoff and soil losses was more significant during late summer and fall season when both flood control and turbidity flow control are necessary for the reservoir and downstream. The occurrence of extreme turbidity flow events during these period is more vulnerable to reservoir operation because the suspended solids that remained water column can be resuspended by vertical mixing during winter turnover period. The study results provide useful information for the development of adaptive management strategy for the reservoir to cope with the expected impact of future climate change.

Prediction of Water Quality at the Inlet of Saemangeum Bay by using Non-point Sources Runoff Simulation in the Mankyeong River Watershed (만경강 유역의 비점오염물질 유출모의를 통한 새만금 만 유입부의 수질 예측)

  • Ryu, Bum-Soo;Lee, Chae-Young
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.6
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    • pp.761-770
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    • 2013
  • This study was carried out to forecast the flow rate and water quality at the inlet of the Saemangeum bay in Korea using the SWMM(Storm Water Management Model) and the WASP(Water Analysis Simulation Program), and to analyze the impacts of pollutant loading from non-point source on the water quality of the bay. The calibration and validation of flow rate and water quality were performed using those from two monitoring points in the Mankyeong river administrated by Korean Ministry of Environment as part of the national water quality monitoring network. When the river flow rate was calibrated and validated using the rainfall intensities during 2011-2012, $R^2$ (i.e., coefficient of determination) was ranged from 0.91 to 0.96. For water qualities, it was shown that $R^2$ of BOD(Biochemical Oxygen Demand) was ranged from 0.56 to 0.86, and $R^2$ of T-N(Total Nitrogen) was from 0.64 to 0.75, and $R^2$ of T-P(Total Phosphorus) was from 0.67 to 0.89. The integrated modeling system showed significant advances in the accuracy to estimate the water quality. Finally, further simulations showed that annual average flow of the river running into the bay was estimated to be $1.439{\times}10^9m^3/year$. The discharged load of BOD, T-N, and T-P into the bay were anticipated to be 618.7 ton/year, 331.5 ton/year, and 40.4 ton/year, respectively.

Test Rig Development for Identification of Rotordynamic Force Coefficients of Squeeze Film Dampers in Automotive Turbocharger Bearing Systems (자동차 터보차저 베어링 시스템에 적용되는 스퀴즈 필름 댐퍼의 동적계수 측정을 위한 실험장치 개발)

  • Hwang, Jisu;Ryu, Keun;Jeung, Sung-Hwa
    • Tribology and Lubricants
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    • v.34 no.1
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    • pp.33-41
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    • 2018
  • This paper describes a new test rig for identification of rotordynamic force coefficients of squeeze film dampers (SFDs) in automotive turbochargers (TCs). Prior studies have mainly concentrated on relatively large-sized SFDs used in aircraft engines, turbocompressors, and turbopumps. The main objective of the current study is to propose a test rig for identification of dynamic force coefficients of small-sized SFDs (a journal diameter of ~11 mm). The current test rig consists of a journal, a SFD cartridge, four support rods, an upper structure, a data acquisition (DAQ) system, and an oil circulation unit. The annular gaps between the journal outer surface and SFD cartridge inner surface create SFD film lands. The damper has two parallel film lands separated by a central groove, having an axial length and depth of 3 mm. Each film land has a length of 4 mm with a $40{\mu}m$ radial clearance. The static load and dynamic impact tests identify the structural characteristics (i.e., stiffness and natural frequency) of the journal and assembled test rig. The measurements show good agreement with predictions. The SFD performance data from this test rig will be used to develop innovative TC rotor systems with improved NVH and reliability characteristics incorporating advanced SFD technology.

Analysis of water purification in the FWS wetland for Agreculture Area (농업지역 내 FWS 인공습지의 수질정화효율 분석)

  • Kang, Chang-Guk;Maniquiz, Marla C.;Son, Young-Gyu;Kim, Lee-Hyung
    • Journal of Wetlands Research
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    • v.12 no.3
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    • pp.39-47
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    • 2010
  • Annually, the scale of agricultural areas in Korea were being reduced as the lands were converted to other land uses. While the rate of productivity were either being maintained or increased, the pollution load from these areas were still greater in magnitude. Although the levels of pollutant concentration released in the agricultural watersheds were minimal, the combined quantities mostly from diffuse sources were high. As a consequence, the Ministry of Environment (MOE) in Korea adopted the use of free water surface (FWS) flow constructed wetlands to reduce the pollutant loadings emitted from agricultural watersheds for the improvement of water quality and protection of aquatic ecosystems. In this study, a constructed wetland treating stream water in an agricultural watershed was monitored since April 2009 subsequent to its completion in December 2008. Satisfactory performance was achieved for TSS, BOD and TP with 26%, 28% and 39% pollutant removal rates, respectively. In addition, the effluent water quality was improved and achieved compliance the national water quality criteria. Results of this study can be useful to establish design parameters and employ proper removal techniques of similar natural treatment systems for future implementation in the country.

DESIGN AND STRUCTURAL ANALYSIS OF DOME ENCLOSURE FOR TRACKING ARTIFICIAL SPACE OBJECTS (인공우주물체 추적용 완전 개폐형 돔의 설계 및 구조해석)

  • Seol, K.H.;Kim, S.J.;Jang, M.;Min, S.W.;Mun, B.S.;Baek, K.M.
    • Publications of The Korean Astronomical Society
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    • v.22 no.4
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    • pp.211-217
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    • 2007
  • We have been making dual dome enclosures which are useful to track artificial space objects at SSNT (Space Science and Technology Lab.) Kyung Hee University. We verified the safety of the dome enclosures using basic design and structure analyses before manufacturing them, and then performed an optimization analysis for economic and safe systems. The dome enclosure has a fully-open type structure to smoothly operate a telescope made in the style of altazimuth mount with very fast tracking. It is also designed to be safe against extreme weather conditions. The general structure of the observatory system consists of the dual dome enclosures at the top of a container. For the structural analyses, we consider the following two methods: (1) gravitational sustain analysis - how the structure supporting the dome withstand the weight of the dome, and (2) wind load analysis that considers the effect of the wind velocity at the region where the observatory is located. The result of overall deformation is found to be less than 0.551mm and the result of equivalent stress is found to be 20.293Mpa, indicating that the dual dome system is reasonably designed. This means structurally to be safe.

Bonding Properties of Steel-reinforced Polymer Cement Mortar Evaluated by Pull-off Test and FEM Modeling (폴리머 시멘트 모르타르의 철근부착력 평가를 위한 인발실험과 모델링)

  • Park, Dong-Cheon;Yoneda, Nobutosi;Cho, Bong-Suk
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.3
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    • pp.216-222
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    • 2014
  • Chloride attack to reinforced concrete structures located in seaside can cause a serious problem of durability and maintenance during the service life. Corrosion of reinforced steel bars in concrete decreases the bond strength and finally causes the detachment of concrete cover. Polymer cement mortar is usually adopted to repair the deteriorated RC structures because of its strong bonding property. The recovered load-carrying capacity after the repair was simulated by non-linear FEM analysis. The properties of concrete, repairing materials, bonding materials and reinforced bar were used as input data. Four types of redispersible polymer powders were used as components of polymer cement mortar. Pull-off tests were carried out to examine the bond properties such as rigidity and strength. Effects of a corrosion inhibitor and the loss of reinforced bars due to the corrosion were also considered in this study. FEM modeling and analysis were conducted to propose the universal model. Physical bonding in the relationship between repair materials and steel reinforced bar is more dominant than chemical bonding.

Development of a Structure for Lunar Lander Demonstrator (달착륙선 지상시험모델의 구조체 개발)

  • Son, Taek-Joon;Na, Kyung-Su;Lim, Jae Hyuk;Kim, Kyung-Won;Hwang, Do-Soon
    • Aerospace Engineering and Technology
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    • v.12 no.1
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    • pp.213-220
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    • 2013
  • Korean Lunar Explorer is planned to be launched in the 2020s according to national space development strategy. The Lunar Explorer will be developed as two unmanned light weight models: a lunar orbiter and a lunar lander. The Lunar Explorer's structure should be designed to have light weight due to constraints from launcher as well as to provide structural safety against launch load, in-orbit condition and landing condition and to serve accommodation space for mission equipment. Core technology related to structural development of lunar explorer should be developed in advance. Especially, for lunar lander, technology for developing landing gear which enables lander to land safely on lunar surface is required essentially. This paper deals with structural development of lunar lander ground test model including design, manufacturing and test.