• 제목/요약/키워드: Environment chamber

검색결과 852건 처리시간 0.023초

벼논에서 자동 챔버와 수동 챔버를 이용한 CH4 배출량 비교 (Comparison of CH4 Emission between Auto Chamber and Manual Chamber in the Rice Paddy)

  • 정현철;최은정;이종식;김건엽;이선일
    • 한국기후변화학회지
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    • 제9권4호
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    • pp.377-384
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    • 2018
  • The chamber method is widely used for measuring methane emission from paddy rice fields. The closed static chamber has advantages of easy installation and removal in the field and low manufacturing cost. However, the manual chamber method requires a lot of labor and has a limited sampling time and frequency. To overcome the disadvantages of the manual chamber, the auto-chamber system is used for measuring methane emission. We compared the differences in methane flux between the auto-chamber and manual chamber. To investigate methane emissions by the two methods, a chamber was installed for each of the following treatments : control without rice straw (NA), spring plowing after autumn rice straw application (SPRA) and autumn plowing after autumn rice straw application (APRA). The total methane emission was lowest in the control and highest in APRA with both methods. There was no significant difference in total methane emission between the methods, but dynamic fluctuation in methane with temperature change was accurately measured in the auto-chamber. Measuring methane emission with an auto-chamber system is expected to reduce uncertainty and increase accuracy, accompanied by labor reduction.

밭토양에서 챔버 위치와 작물체 유·무에 따른 아산화질소 배출량 차이 분석 (The Differences of Nitrous Oxide (N2O) Emissions as Crop Presence and Location of Gas Sampling Chambers in Upland)

  • 정현철;최은정;이종식;김건엽;소규호
    • 한국기후변화학회지
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    • 제7권4호
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    • pp.427-432
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    • 2016
  • Nitrous oxide is one of the main sources of greenhouse gases and its concentration has increased from 273 ppb in 1,750 to 315 ppb in 2005. Specially, nitrogen fertilizer used in agricultural soils is considered as an important source of atmospheric $N_2O$ emission. This study was conducted to estimate the difference of nitrous oxide emission as chamber position on furrow and ridge and crop existence in gas sampling chamber on upland. Four treatments used in this experiment were (1) no-fertilizer without crop in chamber on ridge, (2) fertilizer application without crop in chamber on ridge, (3) fertilizer application with crop in chamber on ridge, (4) fertilizer application without crop in chamber on ridge and furrow. Nitrous oxide emission at fertilizer application with crop in chamber on ridge were the highest while were the lowest at no-fertilizer without crop in chamber on ridge. There was no significant difference of nitrous oxide emission by chamber position, but total emission by crop existence in chamber was significant difference. Therefore, in order to estimate greenhouse gases emission using chamber method in upland, it should be considered in correlation with crop existence in chamber and characteristic changes like as the soil moisture, microbial flora by crop growth stage.

스모그 챔버를 이용한 이차 초미세유기먼지의 최근 연구 동향 (Review of Recent Smog Chamber Studies for Secondary Organic Aerosol)

  • 임용빈;이승복;김화진;김진영;배귀남
    • 한국대기환경학회지
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    • 제32권2호
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    • pp.131-157
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    • 2016
  • A smog chamber has been an effective tool to study air quality, particularly secondary organic aerosol (SOA), which is typically formed by atmospheric oxidation of volatile organic compounds (VOCs). In controlled environments, smog chamber studies have validated atmospheric oxidation by identifying, quantifying and monitoring products with state-of-art instruments (e.g., aerosol mass spectrometer, scanning mobility particle sizer) and provided chemical insights of SOA formation by elucidating reaction mechanisms. This paper reviews types of smog chambers and the current state of smog chamber studies that have accomplished to find pathways of SOA formation, focusing on gas-particle partitioning of semivolatile products of VOC oxidation, heterogeneous reactions on aerosol surface, and aqueous chemistry in aerosol waters (e.g., cloud/fog droplets and wet aerosols). For future chamber studies, then, this paper discusses potential formation pathways of fine particles that East Asia countries (e.g., Korea and China) currently suffer from due to massive formation that gives rise to fatal health problems.

열환경 챔버 제어를 위한 PID 튜닝기법 연구 (A Study on PID Tuning Technique of a Thermal Environment Chamber)

  • 신영기;양훈철;태춘섭;장철용;조수;김영일
    • 설비공학논문집
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    • 제17권11호
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    • pp.1072-1078
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    • 2005
  • The present study has been conducted to tune a PID controller for large thermal systems such as a thermal environment chamber. In spite of large thermal mass of the thermal chamber under test, its response delay time was found to be negligible mainly due to high air recirculation rate. In general, heating and cooling capacities tend to be small compared the size of a thermal environment chamber, which leads to long transient periods of one hour or so. In the study, a PI tuning method is suggested which makes system responses faster while reducing overshoots and hunting by utilizing efficiently proportional band of actuators.

Sensitivity Study of the Flow-through Dynamic Flux Chamber Technique for the Soil NO Emissions

  • Kim Deug-Soo
    • Journal of Korean Society for Atmospheric Environment
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    • 제21권E3호
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    • pp.75-85
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    • 2005
  • A mathematical sensitivity analysis of the flow-through dynamic flux chamber technique, which has been utilized usually for various trace gas flux measurement from soil and water surface, was performed in an effort to provide physical and mathematical understandings of parameters essential for the NO flux calculation. The mass balance equation including chemical reactions was analytically solved for the soil NO flux under the steady state condition. The equilibrium concentration inside the chamber, $C_{eq}$, was found to be determined mainly by the balance between the soil flux and dilution of the gas concentration inside the chamber by introducing the ambient air. Surface deposition NO occurs inside the chamber when the $C_{eq}$ is greater than the ambient NO concentration ($C_{0}$) introducing to the chamber; NO emission from the soil occurs when the $C_{eq}$ is less than the ambient NO concentration. A sensitivity analysis of the significance of the chemical reactions of NO with the reactive species (i.e. $HO_{2},/CH_{3}O_{2},/O_{3}$) on the NO flux from soils was performed. The result of the analysis suggests that the NO flux calculated in the absence of chemical reactions and wall loss could be in error ranges from 40 to $85\%$ to the total flux.

하수 중 인의 결합 특성 분석 (Analysis of Characteristics of Coupled Phosphorus in the Sewage)

  • 최희정;이승목
    • 한국물환경학회지
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    • 제23권1호
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    • pp.97-102
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    • 2007
  • The present investigation deals to achieve an accurate determination of the phosphorous present in the wastewater samples using the membrane reactor. The study may enable to quantify the dissolved (DP) and adsorbed phosphorous (AP), also the adsorbed phosphorous categorically identified as inorganic coupled phosphorous (DRP) and organic coupled phosphorous (NRP). Moreover, the study has been conducted separately in anaerobic and aerobic chamber. The results obtained showed that dissolved phosphorous only can occur in anaerobic chamber with ca. 25%. The study conducted for adsorbed phosphorous showed that the DRP has the percent composition in anaerobic and aerobic chamber respectively 33% and 40% i.e., 7% more in aerobic chamber. The similar values obtained for NRP was found to be 42% and 60% i.e., 18% more in aerobic chamber. On the other hand while comparing the results for NRP and DRP, it has to be noted that NRP has 9% and 20% more percent composition than DRP respectively in anaerobic and aerobic chamber. Further, the adsorbed phase showed the species Al-P, Fe-P in the aerobic chamber with the quotient of 7.73 mg/g TS (total solid) whereas in the anaerobic chamber it showed the species Fe-P and $Fe(OH)_3$-P with the 7.16 mg/g TS.

스포츠 멀티 인공환경 시스템을 위한 다중압력 일체형 챔버의 구조안전성 평가 (Structural Safety Evaluation of Multi-Pressure Integrated Chamber for Sport-Multi-Artificial Environment System)

  • 이준호;강상모;채재익
    • 한국산학기술학회논문지
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    • 제20권3호
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    • pp.324-328
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    • 2019
  • 스포츠를 위해 제공되고 사용되는 몇 가지 전용 챔버가 공급되어 사용되고 있지만 스포츠 멀티 환경을 동시에 제공할 수 있는 다기능 올인원 챔버는 개발되지 않았다. 본 연구에서는 스포츠 다중 인공 환경 시스템에 사용할 수 있는 다중압력 (양 / 대기 / 음압) 일체형 챔버를 설계하였다. 키가 큰 사용자를 위해 공간을 넓힌 새로운 챔버 디자인을 제시 한 다음 최대 응력과 구조적 안전성검토를 통하여 챔버의 구조해석을 수행하였다. 목표로 하는 허용 압력 조건하에서 쉘과 출입구의 접합부에서 최대 응력이 발생했으며, 챔버 재료의 허용응력을 기준으로 하여 구조안전성 평가를 수행하였다. 다중 압력 일체형 챔버에 대하여 구조해석을 수행한 결과 양압과 음압 조건에 대한 최대 응력이 챔버 재료의 허용응력 보다 훨씬 작은 값이 발생되었으며, 구조안전성 평가 결과 안전율 2 이상을 만족하여 챔버의 최종 시제품의 설계가 구조적으로 안전하다는 것을 확인하였다.

Study on Comparison of Atmospheric and Vacuum Environment of Thermally-Induced Vibration Using Vacuum Chamber

  • Kong, Chang-Duk;Park, Hyun-Bum;Lee, Ha-Seaung
    • International Journal of Aeronautical and Space Sciences
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    • 제11권1호
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    • pp.26-30
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    • 2010
  • The present paper studies the thermally-induced vibration phenomenon of the flexible space boom structure. In order to simulate the thermally-induced vibration phenomenon of the flexible thin boom structure of the spacecraft with the attached tip mass in space, the thermally-induced vibration including thermal flutter is experimentally investigated at various thermal environments using a heating lamp in vacuum chamber. In this experimental study, fluctuating characteristics, natural frequency and thermal strains of the thermally-induced vibration are parametrically investigated at various thermal environment conditions. Finally the thermally-induced vibration of the flexible boom structure of the orbiting earth satellite in solar radiation environment from the earth eclipse region including umbra and penumbra is simulated using the power control of the heating lamp in the vacuum chamber.

플라즈마 챔버의 특성 분석 및 최적 설계를 위한 가상의 시뮬레이션 환경 개발 (Development of Virtual Integrated Prototyping Simulation Environment for Plasma Chamber Analysis and Design (VIP-SEPCAD))

  • 김헌창;설용태
    • 반도체디스플레이기술학회지
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    • 제2권4호
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    • pp.9-12
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    • 2003
  • This paper describes a newly developed simulation environment for analysis and design of a plasma processing chamber based on first principles including complicated physical and chemical interactions of plasma, fluid dynamics of neutrals, and transport phenomena of particles. Capabilities of our simulator, named VIP-SEPCAD (Virtual Integrated Prototyping Simulation Environment for Plasma Chamber Analysis and Design), are demonstrated through a two dimensional simulation of an oxygen plasma chamber. VIP-SEPCAD can provide plasma properties such as spatiotemporal profiles of plasma density and potential, electron temperature, ion flux and energy, etc. By coupling neutral and particle transport models with a three moment plasma model, VIP-SEPCAD can also predict spatiotemporal profiles of chemically reactive species and particles exist in plasma.

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외부 열적 환경 변화에 따른 압전작동기 제어성능 열화 고찰 (Control Performance Investigation of Piezoelectric Actuators under Variation of External Heat Environment)

  • 한영민;문병구;최승복
    • 한국소음진동공학회논문집
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    • 제25권10호
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    • pp.707-713
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    • 2015
  • This paper proposes experimental results for control performance deterioration of a piezoelectric actuator under high temperature conditions due to external heat environment. In this work, a heat environment from 30 ℃ to 190 ℃ is established by a heat chamber which is capable of high temperature of heat environment. Inside the heat chamber, an experimental apparatus consisting of the stack type of piezoelectric actuator, laser sensor, gap sensor and temperature sensor is established. After evaluating temperature dependent blocking force, displacement and time response of a piezoelectric actuator inside the heat chamber, tracking control performances are evaluated under various temperature conditions via proportional-integral-derivative(PID) feedback controller. The desired position trajectory has a sinusoidal wave form with a fixed frequency. Control performances are experimentally evaluated at both room temperature and high temperature and presented in time domain.