• Title/Summary/Keyword: carbon dioxide method

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Acoustic Emission Characteristics of Plasma Sprayed Ceramic Coating Layer after Salt Spray (플라즈마용사 세라믹코팅 피막부식재의 음향방출 특성)

  • 김귀식;박경석;홍용의
    • Journal of Ocean Engineering and Technology
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    • v.15 no.3
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    • pp.69-74
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    • 2001
  • This paper was to investigate of a adhesiveness for the plasma sprayed coating materials did salt spray by acoustic emission method in tensile loadings. The powders used for the coating were nickel aluminum composite powder Ni-4.5wt.%Al and titanium dioxide powder $TiO_2$. These powders were coated on a carbon steel S45C by plasma spray method. The result solution was a 5% NaCl and the slat spray times were 2, 5 and 10 hours respectively. The salt solution penetrated into the surface of the substrate through pore of the coating layer built in the process of plasma spay. Corrosion productions formed on the surface of substrate. The adhesiveness between the substrate and the coating layer is weaken by corrosion and the exfoliation initiated chiefly at the corrosion surface of the substrate. The AE events and energy of the corroded coating specimens decreased as the salt spray times increased.

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Operating Characteristics of Internal Heat Exchanger for $CO_2$ Geothermal Heat Pump in the Heating Mode (난방모드 시 $CO_2$ 지열히트펌프의 내부열교환기에 대한 운전특성)

  • Kim, Jae-Duck;Lee, Sang-Jae;Kim, Seon-Chang;Kim, Young-Lyoul
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.1226-1231
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    • 2009
  • This paper presents operating characteristics of internal heat exchanger(IHX) for $CO_2$ geothermal heat pump in the heating mode. Mass flow rate of $CO_2$, inlet temperatures of $CO_2$ at high and low pressure side were selected as main effect factors by using fractional factorial DOE(Design of Experiments). And RSM(Response Surface Method) was used in optimization phase. The results show that heat transfer rate of IHX increases when either inlet temperature of low pressure side decreases or inlet temperature of high pressure side increases. Effectiveness of IHX increases with increasing of inlet temperature of either high pressure side or low pressure side. Finally, performance contour map was provided over the operation ranges of the main design factors.

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Modeling Fresh Produce Respiration and Designing Modified Atmosphere Package

  • Lee, Dong-Sun
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.13 no.3_4
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    • pp.113-120
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    • 2007
  • The method to characterize the fresh produce respiration was presented with possible application of modified atmosphere package design. Particularly the respiration model based on enzyme kinetics was introduced as function of oxygen and carbon dioxide concentrations. The method to estimate the equilibrated package atmosphere for any package conditions was presented by incorporation of $O_2$ and $CO_2$ permeabilities of the packaging film. Temperature dependences for fresh produce respiration and gas permeation were given by Arrhenius equation and then used to analyze the effect of temperature on the package atmosphere. An example analysis was presented for better understanding of the concept.

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Some Thoughts on LCCO2 of the Railway Track System (철도 궤도시스템의 LCCO2에 관한 소고)

  • Minnu, Tian;Lee, Woo-Chul;Choi, Sang-Hyun;Lim, Nam-Hyoung
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.548-551
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    • 2009
  • The report of the intergovernment panel on climate change(IPCC) concluded that the global warning due to Green-house Gas(GHGs) will be accelerated in the 21th century. The railroad construction sector consumes a great deal of natural resources and energy in construction. maintenance, and demolition stage. In order to establish and perform reducing plan of GHGs of railway track system for effective corresponding the Climate Change Agreement, the evaluation method of the lifecycle CO2 emission if needed. In this research, it was investigates that the research trend for the LCCO2 and the method to estimate the lifecycle carbon dioxide emission amount of the railway track system as quantitative.

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On the Pyrolysis of Polymers III. Identification of Gases from Rubber Pyrolysis by Gas Chromatography (高分子物質의 熱分解에 關한 硏究 (第3報) 合成고무類의 熱分解生成物의 Gas Chromatography에 의한 檢索과 合成고무 確認에의 利用)

  • Chwa-Kyung Sung
    • Journal of the Korean Chemical Society
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    • v.7 no.2
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    • pp.115-121
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    • 1963
  • Aliphatic hydrocarbon gases from rubber pyrolysis have been identified by gas chromatography with tetraethyleneglycol dimethylether column. Rubbers used in this work are polyisoprene, SBR, NBR, polybutadiene, buthyl rubber, polychloroprene and polyurethane rubber. The chromatogram is characteristic for each polymer. Author proposes a method of identification of synthetic rubbers by gas chromatograph of pyrolyzed gas. Sample is pyrolyzed at $450^{\circ}C$ under nitrogen or more effectively helium and gaseous portion, which eliminated liquid condensate, is passed to the column. The appearance of exclusively large peak of isoprene, isobutylene and carbon dioxide shows the presence of polyisoprene, polyisobutylene and polyurethane, respectively. Large peak of butadiene will appear in case of polybutadiene, SBR and NBR, but SBR can be identified through the styrene peak in gas chromatogram of liquid pyrolyzate and NBR can be identified by the evolution of hydrogen cyanide during pyrolysis. Polychloroprene is identified by the evolution of hydrogen chloride. This method could be applied to the identification of copolymer or polymer blend.

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A Comparative Study on the Aerobic Biodegradation of the Continuous and Intermittent Aeration in Bin Composting System

  • Hong, Ji-Hyung;Choi, Byoung-Min;Park, Keum-Joo
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.42
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    • pp.61-67
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    • 2000
  • Composting of hog manure amended with sawdust trials lasted three weeks and used pilot-scale in bin composting system. Results showed that the rise temperature and carbon dioxide evolution in compost during the composting decomposition process were affected by the aeration method, pH, C/N, moisture content, bulk density and particle size distribution. No significant differences existed in biophysical properties of the composit produced from the continuous and intermittent aeration method. The intermittent aeration was very successful in compost odor control and required less time to reach stability than the continuous aeration.

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Acoustic Emission Characteristics of Plasma Sprayed Ceramic Coating Layer after Salt Spray (플라즈마용사 세라믹코팅 피막부식재의 음향방출 특성)

  • 김귀식;박경석;홍용의
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.05a
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    • pp.344-349
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    • 2001
  • This paper was to investigate of a adhesiveness for the plasma sprayed coating materials did salt spray by acoustic emission method in tensile loadings. The powders used for the coating were nickel aluminum composite powder Ni-4,5wt.%Al and titanium dioxide powder Ti02. These powders were coated on a carbon steel S45C by plasma spray method. The salt solution was a 5% NaCl and the salt spray times were 2, 5 and 10 hours respectively. The salt solution penetrated into the surface of the substrate through pore of the coating layer built in the process of plasma spay. Corrosion productions formed on the surface of substrate. The adhesiveness between the substrate and the coating layer is weaken by corrosion and the exfoliation initiated chiefly at the corrosion surface of the substrate. The AE events and energy of the corroded coating specimens decreased as the salt spray times increased.

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Investigate on the rate of change of CO concentration in a tunnel under changed position of the jet fans by using numerical method (제트 팬 가동위치에 따른 장대터널 내 CO 농도 변화율에 대한 전산해석)

  • Min, Jae-Hong;Kim, Dae-Hyun;Chung, Jin-Taek
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2765-2770
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    • 2008
  • The purpose of tunnel ventilation system for long road tunnels is to keep certain levels of Visibility Index and the concentration of CO. Additional equipments such as jet fans are used in road tunnel to discharge pollutants in the road tunnel. The control algorism of tunnel ventilation system takes the value of sensors as input, and then gives the operation method of jet fans in tunnel as output. Information on the variation of CO concentration in tunnel when jet fans are running is needed to minimize their operation time. Numerical analysis is used in this paper because of the difficulty of conducting experiments under standard condition for ventilation of road tunnel. The concentration of CO has been calculated by using 3-dimensional CFD under transient condition with speed of cars, quantity of air ventilation, and the results for various operation position of jet fans are compared.

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Development of An Industrial Complex Steam Network Optimization Method Using Steam Networking Matrices(SNMs) (Steam Networking Matrices(SNMs)를 이용한 산업 단지의 스팀 네트워크 최적화 방법론 개발)

  • Kim, Sang-Hun;Chae, Song-Hwa;Yoon, Sung-Geun;Park, Sun-Won
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.12
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    • pp.1184-1190
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    • 2006
  • Most chemical companies try to maximize their energy efficiencies due to high oil price and reinforcement of environmental regulation. An individual factory continuously has tried to reduce energy consumption or carbon dioxide discharge for high profit. Nevertheless, it is found that waste heat is disposed with forms of low or medium pressure steams. It can be improved by the aspect of entire industrial complex. Therefore, we have developed a steam network optimization method using Steam Networking Matrices(SNMs) in this research. Results from an illustrative example show that energy consumption can be reduced by optimizing steam exchange networks.

Genetic algorithm in mix proportion design of recycled aggregate concrete

  • Park, W.J.;Noguchi, T.;Lee, H.S.
    • Computers and Concrete
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    • v.11 no.3
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    • pp.183-199
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    • 2013
  • To select a most desired mix proportion that meets required performances according to the quality of recycled aggregate, a large number of experimental works must be carried out. This paper proposed a new design method for the mix proportion of recycled aggregate concrete to reduce the number of trial mixes. Genetic algorithm is adapted for the method, which has been an optimization technique to solve the multi-criteria problem through the simulated biological evolutionary process. Fitness functions for the required properties of concrete such as slump, density, strength, elastic modulus, carbonation resistance, price and carbon dioxide emission were developed based on statistical analysis on conventional data or adapted from various early studies. Then these fitness functions were applied in the genetic algorithm. As a result, several optimum mix proportions for recycled aggregate concrete that meets required performances were obtained.