• Title/Summary/Keyword: 선회운동

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Numerical simulation of VOC decomposition in an arc plasma reactor (수치해석 기법을 이용한 아크 플라즈마 반응기의 VOCs 분해성능 평가연구)

  • Park, Mi-jeong;Jo, Young-min
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.8
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    • pp.1-7
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    • 2016
  • A range of techniques have been being developed to remove the volatile organic compounds from paining processes. High temperature decomposition of harmful VOCs using arc plasma has recently been proposed, and this work analyzed the extreme hot process by computer-aided fluid dynamics prior to the reactor design. Numerical simulations utilized the conservation equations of mass and momentum. The simulation showed that the fluid flowed down along the inner surface of the centrifugal reactor by forming intensive spiral trajectories. Although the high temperature gas generated by plasma influences the bottom of the reactor, no heat transfer in radial direction appeared. The decomposition efficiency of a typical VOCs, toluene, was found to be a maximum of 67% across the reactor, which was similar to the value (approximately 70%) for the lab-scale test.

A study on the radiation effect of silicon solar cells in a low Earth orbit satellite by using high energy electron beams (고에너지 전자빔을 이용하여 저궤도 인공위성의 실리콘 태양센서의 내방사선 특성 연구)

  • Chung, Sung-In;Lee, Jae-Jin;Lee, Heung-Ho
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.45 no.3
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    • pp.1-5
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    • 2008
  • This paper analyzes on the radiation effect of silicon solar cells in a low Earth orbit satellite by using high energy electron beams. Generally, the satellite circling round in a low orbit go through Van Allen belt, in which electronic components are easily damaged and shortened by charged particles moving in a cycle between the South Pole and the North Pole. For example, Single Event Upset (SEU) by radiation could cause electronic devices on satellite to malfunction. From the ground experiment in which we used the high energy electron beam facility at Knrea Atomic Energy Research Institute (KAERI), we tried to explain sun sensor degradations on orbit could he caused by high energy electrons. While we focused on the solar cells used for light detectors, We convince our research also contributes to understand the radiation effect of solar cells generating electric powers on satellites.

Politics of Candlelight Protest and Democratic Theories in Korea (촛불의 정치와 민주주의 이론: 현실과 이론, 사실과 가치의 긴장과 균형)

  • Jaung, Hoon
    • Korean Journal of Legislative Studies
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    • v.23 no.2
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    • pp.37-66
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    • 2017
  • Massive civic protests and consequent presidential impeachment requires a serious revisiting to democratic theories of Korean democracy. This paper explores the strengths and limitations of macro and micro approaches. Changes in democratic realities was manifested on three fronts. First, the rise of new political subject, that is, participants to massive protest. Second, changing nexus between representative institutions and civic protests. Third, parliamentarization of presidential democracy. Specifically macro approach has changed its negative assessment of democracy into positive evaluation. Macro theory has to revisit it's notion of 'minjung' to cope with the rise of new subject. Also macro approach has to struggle with the declining role of civic organizations and political activists. Micro approach has to deal with new mode of networking among citizens and to unravel the evolving relation between democratic institutions and civic protests. In sum, theories need to expand the analytic scope, to revitalize analytic tools and to rebalance value judgment and analytical efforts.

A Numerical Analysis of Flow Characteristics in a Heat Recovery Steam Generator with the Change of Inlet Flow Conditions (배열회수보일러(HRSG)의 입구유동 경계조건에 따른 유동특성 변화에 관한 연구)

  • Kim, Tae-Kwon;Lee, Boo-Yoon;Ha, Ji-Soo
    • Journal of the Korean Institute of Gas
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    • v.15 no.3
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    • pp.53-57
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    • 2011
  • The present study has been carried out to analyze the flow characteristics of a heat recovery steam generator with the change of inlet flow conditions by using numerical flow analysis. The inlet of HRSG corresponds the outlet of gas turbine exit and the flow after gas turbine has strong swirl flow and turbulence. The inlet flow condition of HRSG should be included the exit flow characteristics of gas turbine. The present numerical analysis adopted the flow analysis result of gas turbine exit flow as a inlet flow condition of HRSG analysis. The computational flow analysis result of gas turbine exit shows that the maximum axial velocity appears near circular duct wall and the maximum turbulent kinetic energy and dissipation rate exist relatively higher gradient region of axial velocity. The comparison of flow analysis will be executed with change of inlet turbulent flow condition. The first case is using the inlet turbulent properties from the result of computational analysis of gas turbine exit flow, and the second case is using the assumed turbulent intensity with the magnitude proportional to the velocity magnitude and length scale. The computational results of flow characteristics for two cases show great difference especially in the velocity field and turbulent properties. The main conclusion of the present study is that the flow inlet condition of HRSG should be included the turbulent properties for the accurate computational result of flow analysis.

An Automatic Transfer System of the Path for an Unmanned Machine in the Greenhouse (온실내 무인작업기를 위한 경로 자동변환 시스템 개발)

  • 김창수;이대원;이승기
    • Journal of Bio-Environment Control
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    • v.9 no.4
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    • pp.237-243
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    • 2000
  • Agricultural machine is currently operated by man power in the greenhouse, which is oppressively hot and humid, and is for a farmer not to work in comfortable circumstances. In the future, agricultural machine will not have to operate by man power, but it will need do by unmanned power. In order to put into the automatic and unmanned operation of agricultural machine, this system was designed and built to move through the fixed path in the greenhouse. This system was composed of guiders(wires), a limit switch, an operating equipment, its software for automatizing a machine in the greenhouse. The guider was connected between the wall pillars, and the equipment was able to slide over the fixed path made of the guider, by rectilinear and rotational motion. A micro mouse was developed with a stepping motor to calculate on the success rate of its operation with the system As might be expected, this system with the micro mouse was moved the moved the paths with a success rate of 100% on the flat plane surface in our laboratory. However, on the sand plane or the other materials plane, the success rate was not better than 80%. If the micro mouse were well operated, the success rate was would be 100%. Based on the results of this research, this system would be expected to operate well on the path made of a simple wire.

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Numerical Simulation of Sloshing Test for Fuel Tank of Rotorcraft (회전익항공기용 연료탱크 슬로싱 시험 수치해석)

  • Kim, Hyun-Gi;Kim, Sung Chan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.7
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    • pp.687-693
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    • 2016
  • The rapid turning and acceleration movement of a rotorcraft leads to a sloshing phenomenon in the fuel tank. Sloshing caused by rapid movement can affect the internal components by creating an excessive load. In severe situations, the resulting damage to the internal components and pipes can also lead to the tearing of the fuel tank itself. Therefore, to improve the survivability of the crew, the internal components of the fuel tank must be designed to retain their structural soundness during the sloshing phenomenon. In order to accomplish this, the sloshing load acting on the components first needs to be determined. This paper investigates the sloshing load applied to the internal components by performing numerical analysis for rotary-wing aircraft fuel tanks in the sloshing test. Fluid-Structural Interaction (FSI) analysis based on smoothed particle hydrodynamics (SPH) is conducted and the conditions specified in the US military standard (MIL-DTL-27422D) are employed for the numerical simulation. Based on this numerical simulation, by analyzing the load applied to the internal components of the fuel tank due to the sloshing phenomenon, the possibility of obtaining the design data by numerical analysis is examined.

Formation of Alteration Minerals in Gouges of Quaternary Faults at the Eastern Blocks of the Ulsan Fault, Southeastern Korea (울산단층 동부지역 제4기단층 비지대내 변질광물의 형성)

  • Chang, Tae-Woo;Chae, Yeon-Joon;Choo, Chang-Oh
    • Journal of the Mineralogical Society of Korea
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    • v.18 no.3 s.45
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    • pp.205-214
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    • 2005
  • Some Quaternary faults developed in the eastern block of the Ulsan fault are Gaegok 1, Gaegok 2, Singye, Madong, Wonwonsa and Jinhyeon faults, which are characterized by thin gouge and narrow cataclasitic tones. This study was performed to emphasize the role of mineral alteration and microtexture in response to hydrothermal alteration of fault gouges during fault activity, using XRD, EPMA, BSE (backscattered electron image), and K-Ar age dating methods. Alteration minerals in fault gouges were formed in the age range of $44.3\~28.9Ma$ by hydrothermal alteration attributed to fault activity. XRD results show that fault gouges consist predominantly of clay minerals, quartz and feldspars. Clay minerals formed in the gouge zones are mainly composed of smectite with trace chlorite, illite and kaolinite. The evidence to support the hydrothermal alteration of preexisting minerals due to fault activity are easily recognized at the host rocks in contact with gouges zones. Injected gouge and calcite veins indicate that they were originated from multiple deformation by repeated fault activity. Gouge with green or greenish grey color, for example Jinhyeon fault, contains higher $Al_2O_3$ and lower MgO and CaO compared to those with reddish color. Various colors of fault gouge are intimately related to the chemical compositions of main constituent mineral as well as mineral assemblage.

Cambodia's 2018 General Elections: The Dissolution of Cambodian National Rescue Party and Regressive Electoral Authoritarianism (캄보디아의 2018년 총선: 캄보디아구국당 해산과 퇴행적 선거권위주의)

  • JEONG, Yeonsik
    • The Southeast Asian review
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    • v.28 no.4
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    • pp.197-221
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    • 2018
  • The Cambodian People's Party swept all 125 assembly seats with 76.78% of the vote in 2018 general elections. The Cambodian National Rescue Party, having been dissolved by court, was excluded from the election and attempted to nullify the legitimacy of the election by demanding its supporters to boycott the election. The Cambodian People's Party launched a campaign encouraging to vote in a desperate need to thwart the boycott movement. The election then became an unprecedented kind of competition the winner of which is decided not by the percentage of the vote but by turnout. The Cambodian People's Party was the winner with the high turnout of 82.89%, securing the means to defend the legitimacy of the election. The potential supporters of the Cambodian National Rescue Party spread out with about a million voters switching to support the Cambodian People's Party. Over a half million invalid votes that unequivocally voiced opposition to the Cambodian People's Party were not sufficient to deny the legitimacy of the election. Having experienced the fierce competition in the 2013 general elections that threatened to end its rule, the Cambodian People's Party decided to secure its power in the upcoming election and executed a tactic designed to remove the rival party through legal means. Competition being removed, the Cambodian political system decayed back to hegemonic electoral authoritarianism from competitive electoral authoritarianism to which it had mad gradual progress through the general elections in the past.