• Title/Summary/Keyword: 불활성 가스

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Effect of the Impeller Rotation Speed and Inert Gas Flow Rate on Degassing Rate in the A356 Aluminum Melt (임펠러 회전속도와 불활성 가스 유량이 A356 알루미늄 용탕의 탈가스 속도에 미치는 영향)

  • Hyeok-In Kwon;Hoe-Gyung Jeong;Seong-Il Jeong;Ji-Woo Park;Min-Su Kim
    • Journal of Korea Foundry Society
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    • v.43 no.6
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    • pp.271-278
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    • 2023
  • In the present study, A356 melt degassing experiments were conducted under various impeller rotation speed and inert gas flow rate conditions to determine changes in the melt temperature, composition and density during a degassing treatment. The melt temperature was found to decrease gradually as the degassing time increased, but a clear correlation between the impeller rotation speed or inert gas flow rate and the melt heat loss could not be confirmed. Regardless of the impeller rotation speed or inert gas flow rate, the Mg and Ti contents in the A356 melt scarcely changed, even after degassing for more than 10 minutes, while Sr contents decreased at the maximum degassing rate of 70 ppm. From a quantitative analysis of the degassing rate under each experimental condition based on the hydrogen concentration in the melt derived from the melt density and the degassing model equation, the inert gas flow rate was found to affect the degassing rate rather than the impeller rotation speed under the degassing operation condition employed in the present study.

Flame Extinguishing Concentrations and Flue Gas Compositions of n-Heptane by Mixed Inert Gas Agents (불활성 가스계 혼합소화약제의 n-Heptane 불꽃소화농도 및 배가스 조성)

  • 김재덕;김영래;홍승태;이성철
    • Fire Science and Engineering
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    • v.16 no.3
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    • pp.77-83
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    • 2002
  • We measured flame extinguishing concentration and flue gas composition in the n-heptane fuel cup-burner system using inert gas agents such as nitrogen, argon, carbon dioxide and their mixtures. The flame extinguishing concentration of binary gaseous mixture was well predicted by model which contains the flame extinguishing concentration and composition of pure components. The higher average specific gravity of the mixed inert gas agents, the more excellent flame extinguishing performance. And the structure of enclosed space also affects the fire extinguishing. The composition of carbon dioxide in the flue gas was decreased with increasing extinguishing agent used. Nitrogen monoxide production is not related with increasing nitrogen, but increased at rapid mass flow rate of air in the cup-burner.

Effect of Oxyfluorination of Activated Carbon Fibers on Adsorption of Benzene Gas Causing Sick House Syndrome (새집증후군 유발 벤젠가스 흡착에 미치는 활성탄소섬유의 함산소불소화 영향)

  • Lim, Hyung Soon;Kim, Min-Ji;Kong, Eun Young;Jeong, Jin-do;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.29 no.3
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    • pp.312-317
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    • 2018
  • In this study, activated carbon fibers (ACFs) were treated by oxy-fluorination to improve the adsorption property of benzene gas, one of the gases causing sick house syndrome. Surface properties and pore characteristics of oxyfluorinated activated carbon fibers were confirmed by X-ray photoelectron Spectroscopy (XPS) and Brunauer-Emmett-Teller (BET), and adsorption properties of benzene gas were evaluated by gas chromatography (GC). As a result of XPS data, it was confirmed that the fluorine functional groups on activated carbon fibers surface increased with increasing the fluorine partial pressure. The specific surface area of all samples decreased after the oxyfluorination treatment, but the micropore volume ratio increased when the fluorine partial pressure was at 0.1 bar. The oxyfluorinated activated carbon fibers adsorbed 100 ppm benzene gas for an 11 h, it was found that the adsorption efficiency of benzene gas was improved about twice as much as that of untreated ones.

Comparison of the Physical Properties for Alternative Eire Extinguishing of Pure and Mixture Component of Inert Gases (불활성가스계 단일 성분 및 혼합물 성분의 대체 소화제의 물성 비교)

  • 김재덕;이광진;한순구;이윤우;노경호
    • Fire Science and Engineering
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    • v.18 no.2
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    • pp.12-19
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    • 2004
  • The commercially available IG-541 extinguished agent composed of inert gases was developed for environmental protection. The extinguished agents were considered in terms of physical properties, efficient characteristic, environment, stability, and economical efficiency. The pure and mixture components of physical properties of $N_2$, Ar and $CO_2$ were chosen and compared. The physical properties of density, viscosity and surface tension of inert gases were plotted with the molar ratios of $N_2$/$CO_2$ and Ar/$CO_2$ in terms of a temperature. The extinguished agent in the composition of $N_2$, Ar and $CO_2$, 50/40/10 (mol %) showed relatively high density, low viscosity and moderate surface tension, therefore it was suitable for the alternative extinguished agents.

계면활성제를 이용한 불균질 매질에서의 유기오염물(NAPL)의 정화효율에 관한 실험

  • 서형기;이민희;정상용
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2001.09a
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    • pp.176-179
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    • 2001
  • 비 수용성 유기오염물(NAPL; non-aqueous phase liquid)로 오염된 불균질 토양을 계면활 성제를 이용하여 정화할 경우 효율성을 알아보기 위해 칼럼 및 박스 실험을 실시하였다. 불 균질한 지하 내부구조는 정화효과에 커다란 영향을 끼치는 것으로 알려져 있으나 이에 대한 연구는 매우 미비한 형편이다. 2차원 불균질 분포를 잘 나타내주는 박스실험을 통하여 실제 지하매질에 가까운 조건에서 실험을 실시하였다. PCE(tetrachloroethylene)와 xylene이 NAPL로 올리에마이드(01eamide)가 비이온-계면활성제로 이용되었으며, 1%용액과 증류수를 주입하여 NAPL을 세정하였고 가스크로마토그래피를 이용하여 NAPL의 농도를 분석하였다. 계면활성제를 주입할 경우가 증류수를 주입할 때보다 최대유출농도가 약 200배 정도가 높게 나타났으며 빠른 시간 내에 대부분의 NAPL이 정화되었다. 본 실험을 통하여, 불균질 매질에서의 계면활성제를 이용한 토양세정방법의 효율성이 정량화 되었으며, 계면활성제를 이용한 채수주입법의 현장 적용가능성을 확인하였다.

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Influence of Inert Gas on the Configuration Characteristics of Premixed Turbulent Propagating Flames of Hydrogen Mixtures (수소 예혼합 난류전파화염의 화염형상 특성에 미치는 불활성 가스의 영향)

  • 나까하라마사야;키도히로유끼;김준효
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.4
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    • pp.632-640
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    • 2004
  • The purpose of this study is to clarify the influence of inert gas on the configuration characteristics of premixed turbulent propagating flames of hydrogen mixtures. Inert gas is changed to $N_2$, Ar, $CO_2$ and He keeping the laminar burning velocity of mixtures nearly the same value. A laser tomography technique was used to obtain the flame shape, and quantitative analyses were performed. The result shows that in the wrinkled laminar flame region, the surface area of turbulent flame is slightly dependent on the equivalence ratio and the kind of inert gas. It is also shown the region of convex part of flame toward the unburned gas is greater than that of toward the burned gas regardless of the kind of inert gas.

PECVD에 의한 다이아몬드성 탄소박막의 증착기구에 관한 연구

  • Kim, Han;Joo, Seung-Ki
    • Proceedings of the Korean Vacuum Society Conference
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    • 1994.06a
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    • pp.54-69
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    • 1994
  • 메탄을 원료가스로 하여 ppECVD에 의해 다이아몬드성 탄소(DLC) 박막을 형성하였 으며 이 때 인가전력의 크기 및 주파수 그리고 보조가스의 종류가 opptical band gapp의 크 기에 미치는 영향에 대하여 연구하였다. DLC 박막의 opptical band gapp은 증착되는 이온의 에너지가 증가할수록 감소하였으며, 불활성 기체를 보조가스로 사용하는 경우 인가전력에 따른 opptical band gapp의 크기가 큰 폭으로 심화되었다. 수소를 보조가스로 사용한 경우는 높은 인가전력(100W)에서 opptical band gapp이 증가하는 것으로 밝혀졌으며 본 연구에서 새로이 제안된 증착기구의 모델에 의해 적절한 설명이 가능하였다.

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Reaction Parameters on the Reactivity in the Preparation of B4C by SHS (자전연소합성법에 의한 B4C분말의 제조에 있어 반응성에 대한 반응변수의 고찰)

  • Shin, Chang-Yun;Yun, Ki-Seok;Park, Yeong-Cheol;Hayk, Nersisyan;Won, Chang-Whan
    • Journal of the Korean Ceramic Society
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    • v.42 no.1
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    • pp.22-27
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    • 2005
  • The preparation of B4C by SHS in $B_{2}O_{3}-Mg-C$ system was investigated in this study. In the preparation of B4C, the effect on reactivity and reaction products of the initial pressure of inert gas in reactor, the content of Mg and C in mixture was investigated. The minimum initial pressure of inert gas in reactor for SHS reaction in this system was 25 atm, and as the pressure increased, the concentration of unreacted Mg decreased and combustion temperature increased. At the initial inert gas pressure in reactor of 25 atm, the optimum composition for the preparation of pure B4C was $2B_{2}O_{3}+6.3Mg +0.94C$. The B4C synthesized in this condition had an irregular shape and the particle size of $1\~3{\mu}m$.

Effects of Inert Gas Composition Variations in Biogas on the Performance of a SI Engine (바이오가스 내의 불활성 가스 성분 변화가 SI 엔진 성능에 주는 영향)

  • Lee, Sunyoup;Park, Seunghyun;Park, Cheolwoong;Kim, Changgi;Lee, Janghee;Woo, Sejong
    • Journal of the Korean Institute of Gas
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    • v.16 no.5
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    • pp.14-20
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    • 2012
  • Biogas can be obtained from biogenic materials through an anaerobic digestion process. Since biogas has low calorific value and its composition significantly varies, appropriate combustion strategies need to be established to obtain stable combustion in engine applications. In this study, efforts have been made to investigate the effects of inert gas composition variations on engine performance and emissions. Results show that the MBT spark timing was advanced and $NO_x$ was reduced as the inert gas in the biogas rose. Moreover, $NO_x$ emission drop in $CO_2$ diluted biogas was more significant than that of $N_2$ due to higher heat capacity of $CO_2$, while THC emissions showed the opposite tendency. Thermal efficiency was increased in $N_2$ case with elevation of $N_2$ due to the decreased heat loss and PMEP. However, there is no difference in $CO_2$ case because of deteriorated flame propagation speed.