• Title/Summary/Keyword: Area-ratio

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Flow Characteristics of Central-Driven Ejector with Design Parameters (중앙구동 이젝터의 설계변수에 따른 유동특성)

  • Park, Sang Kyoo;Yang, Hei Cheon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.8
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    • pp.645-651
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    • 2015
  • The objective of this study is to experimentally investigate the effect of design parameter on the mass ratio of a central-driven ejector. The design parameters are the primary nozzle area and distance ratios, diffuser exit-area ratio and mixing-tube length ratio. The experimental setup was an open-loop continuous circulation system which has a movable nozzle ejector, an electric motor-pump, a water tank, a control panel and high-speed camera unit. We calculated the mass ratio using the measured primary and suction-flow rates with the experimental parameter of primary water-flow rate or pressure. The results showed that the mass ratio increased with the primary nozzle distance ratio and mixing tube length ratio, while the mass ratio decreased with the primary nozzle-area ratio and diffuser exit-area ratio.

An Empirical Study on the Function and Effect of Urban Openspace - Focusing on Urban Roadside Trees - (도시녹지의 기능 및 효과에 대한 실증적 연구 - 도시 가로수를 중심으로 -)

  • 성현찬;민수현
    • Journal of the Korean Institute of Landscape Architecture
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    • v.31 no.2
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    • pp.48-57
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    • 2003
  • The objective of this study is to review and verify whether the functions and effect of roadside trees generally hewn in theory are actually realized in urban roads and how well they are performed if the function and effect are realized. The study was conducted with a focus on 3 functions and effects including roadside tree's urban landscape improvement function (green area visibility ratio), effect of introducing green area within a city, and urban green network building function. The major study results are as follows: First, the average green area visibility ratio of 41 study areas is currently about 25.90%. The green area visibility ratio of commercial area within downtown was lowest among 5 road types. It showed that it is possible to raise the average green area visibility ratio up to 32.49% through roadside tree management and additional plantation. Second, in a section between Paldal Mountain and Suwon City Hall where there is no forest fragments and parks at all, a green area of 4,826 roadside trees represented 2.4% of total area and served as the only linear green area. Third, an analysis of 15 cities in Kyonggi province showed that urban forests are concentrated in outskirts. The suey showed that because forest fragments and parks exist in a form of points in urban areas, roadside trees are the only green areas that link each other and build a network.

Centrifuge Model Tests for the Slope Reinforcement Effect (사면 보강효과 확인을 위한 원심모형실험)

  • 박용원;김병일;박종호;홍성수
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.521-528
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    • 2002
  • This paper presents the results of centrifuge model tests on the reinforced slope by pressure grouting. Tests were performed to investigate the reinforcing effect of grouting. In the tests, slopes of scale factor 1/10 were used changing the space and number of reinforcing bar. Test results are as tile follows; 1. The reinforcing effect increase rapidly with reinforcement area ratio at low value of reinforcement area ratio. 2. At high reinforcement area ratio the increase ratio of reinforcing effect decrease. 3. At same reinforcement area ratio, the reinforcing effect of double reinforcing bar was larger than the single reinforcing bar due to arching effect.

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Comparative analysis of forest fire danger rating on the forest characteristics of thinning area and non-thinning area on forest fire burnt area (산불피해지역에서 숲 가꾸기 실행유무가 산불에 미치는 영향)

  • Lee, Si-Young;Lee, Myung-Woog;Yeom, Chan-Ho;Kwon, Chun-Geun
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.153-156
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    • 2008
  • Comparative analysis of forest fire danger rating on the forest characteristics of thinning area and non-thinning area on forest fire burnt area was studied in this work. To investigate the effect of thinning slash in forest fire, Gangneung-si Wangsan-myeon, Ulgin-gun Wonnam-Myeon, Samchok-si Gagok-Myeon, in which forest fire broke out, were selected. As a result that investigated forest fire danger ratio between thinning slash and non-thinning slash, leeward scorching ratio(36%), crown damage ratio(29%), mortality of branch at the former are higher than those at the latter, leeward scorching ratio of tree, where thinning slash is around, is 10%-20% higher than that of independent tree. So I estimate that thinning slash has a some effect on the intensity of forest fire. And the result to investigate damage of forest fire according to tree species shows that leeward scorching ratio of conifer is 5% higher than that of non-conifer, and mortality of branch of the former is 19% higher than that of the latter. It is considered that forest fire may affect directly to a tree trunk if it diffuse to piled thinning tree because there was no space between thinning trees and trees. Furthermore, it was found that re-ignition had a chance to occur due to lots of piled thinning trees.

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The Impact of Plan Characteristics of Residential Land Development Project on Inner Land Price Change (택지개발사업의 계획특성이 사업지구 지가변동에 미치는 영향)

  • Jang, In-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.8
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    • pp.698-705
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    • 2016
  • The purpose of this study is to analyze the impact which the plan characteristics of Residential Land Development Projects have on land price changes in the project district and to derive policy implications for the efficient promotion of these projects. For this purpose, we analyzed the promotion land price change progress of Residential Land Development Projects step-by-step. After theoretical consideration and a review of the references, 16 plan characteristics of Residential Land Development Projects affecting land price changes were selected ((1) The rate of land price change, (2) Business area, (3) Residential land ratio, (4) Commercial land ratio, (5) Semi-residential land ratio, (6) Neighborhood facilities land ratio, (7) Apartment house ratio, (8) Street ratio, (9) Park & green ratio, (10) Ratio of land for schools, (11) Site development cost for $1m^2$, (12) General residential area ratio, (13) Semi-residential area ratio, (14) Commercial area ratio, (15) Semi-Industrial area ratio, and Natural green area ratio). We used SPSS Version 20.0 to analyze the impact of the 16 selected plan characteristics on the land price changes. As a result, it was found that the land price began to rise two years (before/after?) the appointment of the district and became stabilized after the completion of the project. The plan characteristics that affect the land price changes were found to be the (2) Business area, (4) Commercial land ratio, (6) Neighborhood facilities land ratio, (8) Street ratio, (11) Site development cost for $1m^2$, and (12) General residential area ratio.

Variation of Stress Concentration Ratio with Area Replacement Ratio for SCP-Reinforced Soils under Quay Wall (치환율에 따른 안벽구조물 하부 SCP 복합지반의 응력분담비)

  • 김윤태
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.16 no.1
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    • pp.18-26
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    • 2004
  • In order to accelerate the rate of consolidation settlement, to reduce settlement, and to increase bearing capacity for soft ground under quay, sand compaction pile method (SCP) has usually been applied. SCP-reinforced ground is composite soil which consists of the sand pile and the surrounding soft soil. One of main important considerations in design and analysis for SCP-reinforced soils is stress concentration ratio according to area replacement ratio. In this paper, the numerical analysis was conducted to investigate characteristics of stress concentration ratio in composite ground. It was found that stress concentration ratio of composite ground is not constant as well as depends on several factors such as area replacement ratio, depth of soft soil, and consolidation process. The values of stress concentration ratio increase during loading stage due to stress transfer of composite soil, and reach up to 2.5∼12 according to area replacement ratio at the end of construction. After the end of consolidation, however, these values are converged to 2.5 to 6.0 irrespective of area replacement ratio due to increase in effective stress of soft soil during consolidation process.

Comparison of Vertical Magnification Ratio among Various Areas in Panoramic Radiographs

  • Song, Woong-Kyu;Seok, Hwa-Suk;Kim, Byeong-Rin;Choi, Seong-Ho
    • Journal of Korean Dental Science
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    • v.10 no.2
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    • pp.53-59
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    • 2017
  • Purpose: The objective of the present article is to determine whether there are differences in vertical enlargement ratio among various sites within both jaws in a panoramic radiograph. Materials and Methods: Two hundred and seventy-threeimplant sites in panoramic radiographs were evaluated by two observers. Magnification ratios at various sites in both jaws were calculated and compared with each other. Result: The average vertical enlargement ratio in the panoramic radiograph was 1.264 and this value was larger than original ratio 1.250. Although vertical magnification ratio of maxillary molar area was higher than that of mandibular molar area, every group showed similar magnification ratio in clinical respect. Conclusion: Vertical magnification ratio of the maxillary molar area is statistically higher than that of the mandibular molar area in the panoramic radiograph, but it is clinically negligible.

Repeated Use of Irrigation Water for Paddy Fields in Jedae Cheon Basin (堤大川 流域 畓用水의 反復利用)

  • Ahn, Se-Young;Lee, Keun-Hoo
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.33 no.3
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    • pp.63-72
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    • 1991
  • To investigate the status of repeated use of irrigation water observations of irrigation water were made on dry days during the irrigation periods in 1986 and 1987 crop year. The total area of studied site is 1,441 ha. The site is a major portion of Jedaecheon basin which is located in Bubuk-myeon, Miryang-gun, Gyeongnam Province. The studied area was subdivided into six small blocks. The inflow and outflow of daily irrigation water for these subdivided blocks were checked. Obtained results are as follows : 1. The over all possible ratio of the repeated use of irrigation water in studied area was 48.3%, which means that approximately one half of the surface flow was possible to be repeatedly used as irrigation water in this area. 2. The ratio of repeated use of irrigation water in sloppy paddy area was 4.29%, whereas, the ratio was 21.97% in the plain area. The average figure of this ratio over studied area was estimated as 17.43%.

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Sensitivity Analysis of ILLUDAS Model Parameters Based on Rainfall Conditions (강우조건이 ILLUDAS 모형 매개변수의 민감도에 미치는 영향 분석)

  • Lee, Jong Tae;Kim, Tae Hwa
    • Journal of Korean Society of Water and Wastewater
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    • v.18 no.6
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    • pp.748-757
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    • 2004
  • In this study, we analyzed the sensitivity of parameters which affect the result of ILLUDAS model, in the various rainfall conditions. The three basins including Namgaja, Kings creek, Gray haven were selected for this research. The rainfall conditions are considered in terms of the rainfall frequency, the duration and the distribution. In most cases, the impermeability area ratio, the sewer slope, and the sewer roughness coefficient give more significant effects on the results than others. The results show that as increasing the rainfall frequency, the sensitivity of the parameters, sewer slope and roughness coefficient are rised, while the impermeability area ratio is decreasing. And also, for the duration of rainfall, the impermeability area ratio's sensitivity shows similar tendency. In case of the rainfall distribution, the parameters of the sewer roughness and the impermeability area ratio show more sensitive in Huff distribution. Especially, The impermeability area ratio is the most sensitive parameter in Central blocking and Yen & Chow distributions respectively.

Fabrication of Large Area Stamp with High Aspect Ratio Micro Intaglio Features (고세장비 마이크로 음각 형상을 갖는 대면적 스탬프의 제작)

  • Lee, Byung-Soo;Han, Jeong-Won;Han, Jung-Jin;Lim, Ji-Seok;Yoo, Yeong-Eun;Je, Tae-Jin;Kang, Shin-Ill
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.05a
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    • pp.84-87
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    • 2009
  • This paper describes a novel method for fabricating large area metallic stamp with high aspect ratio micro intaglio features. Micro machined brass master with pillar and larger width groove patterns were electroformed to form inverse structures on the large area metallic stamp. This enabled large area metallic stamp with fine micro high aspect ratio micro intaglio features which were small width groove patterns and quadrilateral hole patterns that cannot be fabricated by direct micro machining process. Fabricated large area metallic stamp with high aspect ratio micro intaglio features was measured and analyzed.

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