• Title/Summary/Keyword: 탄소전환률

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Production of Catechol from Benzene by a Mutant of Pseudomonas sp. (Pseudomonas sp. HW-103 변이주에 의한 Benzene으로부터 Catechol 생산)

  • 황기철;이상협;방원기
    • Microbiology and Biotechnology Letters
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    • v.17 no.3
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    • pp.224-230
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    • 1989
  • For the production of catechol from benzene, bacteria capable of assimilating benzene as a sole carbon and energy source were isolated from soils. Among them, newly isolated strain, KY-114 hay-ing the best ability of producing catechol from benzene was selected and a mutant Pseudomonas sp. HW-103 was developed from Pseudomonas sp. KY-114 by using mutagenesis induced by N-methyl - N'- nitro - N -nitrobo guanidine. The catechol reduction from benzone by Pseudomonas sp. HW-103 was investigated under various conditions. The highest catechol concentration (0.61 g/$\ell$) was obtained in the growth medium (pH 6.5) containing 1% sodium citrate, 0.75% (NH$_4$)$_2$SO$_4$, 0.15% benzene and other minerals at 3$0^{\circ}C$ after incubating of 15hrs. In the catechol production through the reaction with resting rolls, 2.5 g/1 of catechol was produced from 4 g/$\ell$ of benzene after incubation of 10 hrs under the optium conditions, which correponds to 45% of theoretical catechol yield.

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Optimum Condition for Mass Culture of Hairy Roots from Artemisia sylvatica MAX (국내 자생 그늘쑥 (Artemisia sylvatica MAX) 모상근의 대량배양을 위한 최적조건)

  • Shin, Sun-Hee;Yang, Deok-Cho
    • Journal of Plant Biotechnology
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    • v.30 no.1
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    • pp.65-71
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    • 2003
  • This research aims the production of anti-tumor substances through in vitro culture of hairy roots transformed by Agrobacterium rhizogenes in Artemisia sylvatica MAX and the effect of culture conditions on optimum growth of hairy roots. We investigated the optimum medium, pH, carbon source, sucrose, light, Fe and polyamine conditions of various lines of hairy roots (NK3, NK4, YX. NK3-10) induced from Artemisia sylvatica to increase the optimum growth of hairy roots. MS medium was the best for optimum growth of hairy root clone, NK3-S10. The optimum culture period was 4 weeks for NK3-S10. The optimum sucrose concentration was 3.5%. The optimum concentration of FeSO$_4$, spermine and spermidine was 0.1 mM, 10 mM and 100 mM, respectively.

Flexural Behavior of RC Beams Strengthened with CFRP Plate Using Multi-directional Channel-type Anchorage System (다방향 채널형 단부정착장치를 이용한 CFRP판 보강 RC 보의 휨거동)

  • Hong, Ki Nam;Han, Sang Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.2
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    • pp.171-180
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    • 2008
  • The aim of this paper is to clarify the structural performance of RC beams strengthened with Carbon Fibre Reinforced Polymer(CFRP) plates using channel-type anchorage system. Twelve RC beams were specifically designed without and with a channel-type anchorage system, which was carefully detailed to enhance the benefits of the strengthening plates. All the twelve beams were identical in terms of their geometry but varied in their internal reinforcement, concrete strength. All the beams were tested under four point bending and extensively instrumented to monitor strains, cracking, load capacity and failure modes. The structural response of all the twelve beams is then critically analyzed in terms of deformability, strength and failure processes. It is shown that with a channel-type anchorage system, a brittle debonding failure of a strengthened beam can be transformed to an almost ductile failure with well-defined enhancement of structural performance in terms of both deformation and strength.

Mineralization of Cattle Manure Compost at Various Soil Moisture Content (우분퇴비 시용후 토양수분 조절에 따른 질소 및 탄소의 전환)

  • Kim, P.J.;Chung, D.Y.;Chang, K.W.;Lee, B.L.
    • Korean Journal of Environmental Agriculture
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    • v.16 no.4
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    • pp.295-303
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    • 1997
  • To investigate the transformation characteristics of nitrogen and carbon from cow manure compost amended in soil under different moisture conditions, dynamics of nitrogen and carbon were determined periodically for 15 weeks of aerobic incubation at room temperature during July${\sim}$November, 1996. Cow manure compost matured with mixing saw dust was amended with the 4 ratios (0, 2, 4, 6%(wt/wt)) in Ap horizon soil, which collected from green house in Yesan, Chungnam. Moisture was controlled with 0.2, 0.3, 0.4, and 0.5 of mass water conte nt (${\theta}$m) to air dried soil, and water loss was compensated at every sampling. During incubation, soil pH was decreased continuously, that was caused by hydrogen generated from nitrification of ammonium nitrogen. And pH became higher with inclining cow manure compost amendment and water treatment, that meaned the increase of mineralization of organic-N to $NH_4\;^+-N$. Total nitrogen was reduced with increasing water content, but total carbon showed the contrast tendency with that of nitrogen. Therefore, C/N ratio slightly decreased in the low water condition (${\theta}$m 0.2) during incubation, but increased continuously in high water condition over ${\theta}$m 0.4. As a result, it was assumed that soil fertility is able to be reduced in the high water content over available water content. Nitrate transformation rate increased lasting in the low water content less than ${\theta}$m 0.3. Itdropped significantly in the first $2{\sim}3$ weeks of incubation over ${\theta}$m 0.4. In particular, nitrate was not detected in ${\theta}$m 0.5 of water content after the first $2{\sim}3$ weeks. In contrast, ammonium transformation was inclined with increasing water treatment. Nitrogen mineralization rate, which calculated with percentage ratio of (the sum of ex.$NH_4\;^+-N$ and $NO_3\;^--N$)/total nitrogen, was continuously increased in the low water content of ${\theta}$m 0.2 and 0.3. But it saw the different patterns in high water content over ${\theta}$m 0.4 that was drastically declined in the initial stage and then gradually inclined . From the above results, nitrogen transformation patterns differentiated decisively in water content between ${\theta}$m 0.3 and 0.4 in soil. Thus, it is very important for the maintain of suitable soil water content to enhance fertility of soil amended with manure compost. However, excess treatment of manure compost might enhance the possibility of contamination of small watershed and ground water around agricultural area.

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Numerical Study of Methane-hydrogen Flameless Combustion with Variation of Recirculation Rate and Hydrogen Content using 1D Opposed-flow Diffusion Flame Model of Chemkin (Chemkin 기반의 1차원 대향류 확산 화염 모델을 활용한 재순환율 및 수소 함량에 따른 메탄-수소 무화염 연소 특성 해석 연구)

  • Yu, Jiho;Park, Jinje;Lee, Yongwoon;Hong, Jongsup;Lee, Youngjae
    • Clean Technology
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    • v.28 no.3
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    • pp.238-248
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    • 2022
  • The world is striving to transition to a carbon-neutral society. It is expected that using hydrogen instead of hydrocarbon fuel will contribute to this carbon neutrality. However, there is a need for combustion technology that controls the increased NOx emissions caused by hydrogen co-firing. Flameless combustion is one of the alternative technologies that resolves this problem. In this study, a numerical analysis was performed using the 1D opposed-flow diffusion flame model of Chemkin to analyze the characteristics of flameless combustion and the chemical reaction of methane-hydrogen fuel according to its hydrogen content and flue gas recirculation rate. In methane combustion, as the recirculation rate (Kv) increased, the temperature and heat release rate decreased due to an increase in inert gases. Also, increasing Kv from 2 to 3 achieved flameless combustion in which there was no endothermic region of heat release and the region of maximum heat release rate merged into one. In H2 100% at Kv 3, flameless combustion was achieved in terms of heat release, but it was difficult to determine whether flameless combustion was achieved in terms of flame structure. However, since the NOx formation of hydrogen flameless combustion was predicted to be similar to that of methane flameless combustion, complex considerations of flame structure, heat release, and NOx formation are needed to define hydrogen flameless combustion.

An Assessment on the Possibilities to Promote Bicycle Use and a Research on its Determining Factors (자전거 이용활성화 가능성 진단 및 결정요소 도출)

  • Shin, Hee-Cheol;Kim, Dong-Jun;Jeong, Seong-Yub;Moon, Jang-Won
    • Land and Housing Review
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    • v.2 no.2
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    • pp.125-135
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    • 2011
  • Automobile-oriented urban transport system, continued from the past in Korea, is giving rise to inefficiency and social costs in transport sector. With revitalizing usage of bicycle, human-powered transport mode, it is possible to enhance sustainable green growth, improvement of the city-competitiveness, and the quality of life. In this study, the possibility of bicycle usage promotion in Korean cities is examined at 7 points of views. As a result, though the bicycle usage is low now, we figured that there are many positive signs to increase bicycle usage in Korea. Also, we draw a diverse key policies for building green urban transport system that bicycle have a most important role on transport system. So policies to promote bicycle usage are reviewed to analyze on bicycle-oriented 5 cities, in which have high bicycle mode share. By this review, this study could draw 41 key effective policies to 3 aspects (bicycle infrastructure, safety and promotion, and policy sustainability). In addition to, importance of 21 key effective policies about bicycle infrastructure is suggested as considering city's characteristics.

Numerical Study on Thermochemical Conversion of Non-Condensable Pyrolysis Gas of PP and PE Using 0D Reaction Model (0D 반응 모델을 활용한 PP와 PE의 비응축성 열분해 기체의 열화학적 전환에 대한 수치해석 연구)

  • Eunji Lee;Won Yang;Uendo Lee;Youngjae Lee
    • Clean Technology
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    • v.30 no.1
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    • pp.37-46
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    • 2024
  • Environmental problems caused by plastic waste have been continuously growing around the world, and plastic waste is increasing even faster after COVID-19. In particular, PP and PE account for more than half of all plastic production, and the amount of waste from these two materials is at a serious level. As a result, researchers are searching for an alternative method to plastic recycling, and plastic pyrolysis is one such alternative. In this paper, a numerical study was conducted on the pyrolysis behavior of non-condensable gas to predict the chemical reaction behavior of the pyrolysis gas. Based on gas products estimated from preceding literature, the behavior of non-condensable gas was analyzed according to temperature and residence time. Numerical analysis showed that as the temperature and residence time increased, the production of H2 and heavy hydrocarbons increased through the conversion of the non-condensable gas, and at the same time, the CH4 and C6H6 species decreased by participating in the reaction. In addition, analysis of the production rate showed that the decomposition reaction of C2H4 was the dominant reaction for H2 generation. Also, it was found that more H2 was produced by PE with higher C2H4 contents. As a future work, an experiment is needed to confirm how to increase the conversion rate of H2 and carbon in plastics through the various operating conditions derived from this study's numerical analysis results.

Numerical Prediction for Fluidized Bed Chlorination Reaction of Ilmenite Ore (일메나이트광의 유동층 염화반응에 대한 수치적 예측)

  • Chung, Dong-Kyu;Jung, Eun-Jin;Lee, Mi Sun;Kim, Jinyoung;Song, Duk-Yong
    • Clean Technology
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    • v.25 no.2
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    • pp.107-113
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    • 2019
  • Numerical model that considered the shrinking core model and elutriation and degradation of particles was developed to predict selective chlorination of ilmenite and carbo-chlorination of $TiO_2$ in a two stage fluidized bed chlorination furnace. It is possible to analyze the fluidized bed chlorination reaction to be able to reflect particle distribution for mass balances and the chlorination reaction. The numerical model showed an accuracy with error less than 6% compared with fluidized bed experiments. The chlorination degree with particle size change was greater with a smaller particle size, and there was a 100 min difference to obtain a chlorination degree of 1 between $75{\mu}m$ and $275{\mu}m$. This was not shown to such a great extent with variation of temperature ($800{\sim}1000^{\circ}C$), and there was only a 10 min difference to obtain a chlorination degree of 0.9. In the first selective chlorination process, the mass reduction rate approached to the theoretical value of 0.4735 after 180 min, and chlorination changed the Fe component into $FeCl_2$ or $FeCl_3$ and showed nearly 1. In the second carbo-chlorination process, the chlorination degree of $TiO_2$ approached 0.98 and the mass fraction reached 0.02 with conversion into $TiCl_4$. In the first selective chlorination process, 98% of $TiO_2$ was produced at 180 min, and this was changed into 99% of $TiCl_4$ after an additional 90 min. Also the mass reduction rate of $TiO_2$ was reduced to 99% in the second continuous carbo-chlorination process.

Application of Response Surface Methodology in Medium Optimization to Improve Lactic Acid Production by Lactobacillus paracasei SRCM201474 (반응표면분석법을 이용한 Lactobacillus paracasei SRCM201474의 생산배지 최적화)

  • Ha, Gwangsu;Kim, JinWon;Im, Sua;Shin, Su-Jin;Yang, Hee-Jong;Jeong, Do-Youn
    • Journal of Life Science
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    • v.30 no.6
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    • pp.522-531
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    • 2020
  • The aim of this study was to establish the optimal medium composition for enhancing L(+)-lactic acid (LLA) production using response surface methodology (RSM). Lactobacillus paracasei SRCM201474 was selected as the LLA producer by productivity analysis from nine candidates isolated from kimchi and identified by 16S rRNA gene sequencing. Plackett-Burman design was used to assess the effect of eleven media components on LLA production, including carbon (glucose, sucrose, molasses), nitrogen (yeast extract, peptone, tryptone, beef extract), and mineral (NaCl, K2HPO4, MgSO4, MnSO4) materials. Glucose, sucrose, molasses, and peptone were subsequently chosen as promising media for further optimization studies, and a hybrid design experiment was used to establish their optimal concentrations as glucose 15.48 g/l, sucrose 16.73 g/l, molasses 39.09 g/l, and peptone 34.91 g/l. The coefficient of determination of the equation derived from RSM regression for LLA production was mathematically reliable at 0.9969. At optimum parameters, 33.38 g/l of maximum LLA increased by 193% when compared with MRS broth as unoptimized medium (17.66 g/l). Our statistical model was confirmed by subsequent validation experiments. Increasing the performance of LLA-producing microorganisms and establishing an effective LLA fermentation process can be of particular benefit for bioplastic technologies and industrial applications.