• Title/Summary/Keyword: fixed carbon

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Studies on Biological Nitrogen Fixation -III. Influences of organic matter sources, kinds and amount of fertilizer nitrogen on the changes of biological N2-fixation and kjeldahl nitrogen under dark and light condition in submerged paddy soil (생물학적(生物學的) 질소고정(窒素固定)에 관(關)한 연구(硏究) -III. 담수토양(湛水土壤)에서 유기물종류(有機物種類), 질소비종(窒素肥種)과 시비량(施肥量)을 달리했을때 광합성(光合成) 및 타양성질소고정력(他養性窒素固定力)에 미치는 영향(影響))

  • Lee, Sang-Kyu;Lee, Myeong-Gu
    • Korean Journal of Soil Science and Fertilizer
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    • v.20 no.3
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    • pp.261-268
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    • 1987
  • A green house experiment was conducted to find out the differences in the amount of biologically fixed nitrogen and kjeldahl nitrogen on the different soil texture, kinds and amounts of fertilizer nitrogen under light (photosynthetic $N_2$-fixation) and dark (heterotrophic $N_2$-fixation) condition in submerged paddy soil. The reults obtained were summarized as follows; 1. The amount of biologically fixed nitrogen per mg carbon from different organic matter was obtained as 0.13 mg in glucose, 0.09 mg in rice straw, and 0.07 mg in refused mushroom compost and barley straw under 60 days of incubation. 2. Nitrogen fixing activities were decreased with increase of fertilizer nitrogen and those tendency was pronounced more in sandy soil with application of urea than that of ammonium sulfate. 3. The application of ammonium sulfate in sandy soil under light condition was increased the photosynthetic $N_2$-fixation and the applied urea was remarkably reduced the heterotrophic $N_2$-fixation in sandy soil. The proportion of biologically fixed total nitrogen after experiment in sandy soil was obtained as 25% for dark(heterotrophic $N_2$-fixation) and 75% for light (photosynthetic $N_2$-fixation) condition. On the other hand, very similar biological $N_2$-fixing tendency was obtained between kinds of nitrogen fertilizer and two light condition in clayey soil. 4. The kjeldahl nitrogen was remarkably decreased after experiment under dark condition with application of urea than that of light condition with ammonium sulfate, and no remarkable decreasing tendency was obtained in clayey soil between two kinds of fertilizer nitrogen. 5. The high significant positive correlationship was obtained between calculated biological nitrogen fixation by acetylene reducing activity and kjeldahl nitrogen after experiment under light (y=0.8488X-5.9632, $r=0.9928^{**}$, n=21) and dark (y=0.8795X-7.1056, $r=0.9782^{**}$, n=21) condition. In this experiment condition, conversion factors of 6:1 was obtained from biological nitrogen fixation to soil nitrogen.

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Phase Equilibria of Ionic Liquid/Organic Compound/Supercritical CO2 Systems (이온성액체/유기화합물/초임계이산화탄소계의 상평형)

  • Lim, Bang-Hyun;Kim, Jong-Won;Paek, Sang-Min;Son, Bo-Kook;Lee, Yong-Rok;Lee, Chul Soo;Lee, Huen;Ra, Chun-Sup;Shim, Jae-Jin
    • Clean Technology
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    • v.12 no.3
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    • pp.128-137
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    • 2006
  • The volume change of an ionic liquid and the phase separation behavior of room temperature ionic liquid(RTIL)/organic compound mixture in supercritical carbon dioxide were measured in a high pressure view cell. 1-Butyl-3-methylimidazolium hexafluorophosphate ([bmim][$PF_6$]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][$BF_4$]) was used as ionic liquid(IL). and methanol and dimethyl carbonate were used as organic compound. For a fixed amount of [bmim][$PF_6$] the lower critical endpoint (LCEP) pressure, where the liquid phase is split, decreased as increasing the amount of organic compound. The LCEP pressure became higher as the water content of ionic liquid was higher. However, for water contents above a certain value, no LCEP was formed. LCEP appeared 1.0 MPa higher for a mixture with [bmim][$BF_4$] than with [bmim][$PF_6$]. There was almost no difference in the K-point pressures for different types of ionic liquid and for different amounts of organic liquid. When the concentration of ionic liquid([bmim][$PF_6$]) (IL/(IL+MeOH)) in the initial liquid mixture was larger than 5.9 mol% at the LCEP of the mixture, the volume of $L_1$ because larger than the volume of $L_2$. When it was smaller, however, the volume became smaller, too. The volume change of ionic liquid in the presence of carbon dioxide decreased as increasing the temperature, while it increased as increasing the pressure. For temperatures between 313.15 to 343.15K at 300 bar, it was about 123~125 % of the original volume.

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An Effective Block of Radioactive Gases for the Storage During the Synthesis of Radiopharmaceutical (방사성의약품 합성에서 발생하는 방사성기체의 효율적 차단)

  • Chi, Yong Gi;Kim, Dong Il;Kim, Si Hwal;Won, Moon Hee;Choe, Seong-Uk;Choi, Choon Ki;Seok, Jae Dong
    • The Korean Journal of Nuclear Medicine Technology
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    • v.16 no.2
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    • pp.126-130
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    • 2012
  • Purpose : Methode an effective block was investigated to deal with volatile radioactive gas, short lived radioactive waste generated as a result of the routinely produced radiopharmaceuticals FDG (2-deoxy-2-[$^{18}F$]fluoro-D-glucose) and compound with $^{11}C$. Materials and Methods : All components of the radiation stack monitoring and data management system for continuous radioactive gas detection in the air extract system purchase from fixed noble gas monitor of Berthold company. TEDLAR gas sampling bags purchase from the Dongbanghitech company. TEDLAR gas sampling bags (volume: 10 L) connected via paraflex or PTFE tubing and Teflon 3 way stopcock. When installing TEDLAR gas sampling bags in Hot cell on the inside and not radioactive gas concentrations were compared. According to whether the Hot cell inside a activated carbon filter installed, compare the difference in concentration of the radioactive gas $^{18}F$. Comparison of radiation emission concentration difference of module a FASTlab and TRACElab. Results : Activated carbon filter are installed in the Hot cell, a measure of the concentration of radioactive gas was 8 $Bq/m^3$. Without activated carbone filter in the hot cell was 300 $Bq/m^3$. Tedlar bag prior to installation of the radioactive gases a measure of the concentration was 3,500 $Bq/m^3$, $^{11}C$ synthesis of the measured concentration was 27,000 $Bq/m^3$. After installed a Tedlar bag and a measure concentration of the radioactive gases was 300 $Bq/m^3$ and $^{11}C$ synthesis was 1,000$Bq/m^3$. Conclusion : $^{11}C$ radioactive gas that was ejected out of the Hot cell, with the use of a Tedlar gas sampling bag stored inside. A compound of 11C is not absorbed onto activated carbon filter. But can block the release out by storing in a Tedlar gas sampling bag. We was able to reduce the radiation exposure of the worker by efficient radiation protection.

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A Study on the Adsorption and Desorption Characteristics of Metal-Impregnated Activated Carbons with Metal Precursors for the Regeneration and Concentration of Ammonia (암모니아의 재생 및 농축을 위한 금속 전구체에 따른 금속 첨착 활성탄의 흡착 및 탈착 특성에 관한 연구)

  • Cho, Gwang Hee;Park, Ji Hye;Rasheed, Haroon Ur;Yoon, Hyung Chul;Yi, Kwang Bok
    • Clean Technology
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    • v.26 no.2
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    • pp.137-144
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    • 2020
  • Metal-impregnated activated carbons were prepared via ultrasonic-assisted impregnation method for regeneration and low ammonia concentration. Magnesium and copper were selected as metals, while chloride (Cl-) and nitrate (NO3-) precursors were used to impregnate the surface of activated carbon. The physical and chemical properties of the prepared adsorbents were characterized by TGA, BET, and NH3-TPD. The ammonia breakthrough test was carried out using a fixed bed and flowing ammonia gas (1000 mg L-1 NH3, balanced N2) at 100 mL min-1, under conditions of temperature swing adsorption (TSA) and pressure swing adsorption (PSA, 0.3, 0.5, 0.7, 0.9 Mpa). The adsorption and desorption performance of ammonia were in the order of AC-Mg(Cl) > AC-Cu(Cl) > AC-Mg(N) > AC-Cu(N) > AC through NH3-TPD and TSA and PSA processes. AC-Mg(Cl) using MgCl2 showed the average adsorption amount of 2.138 mmol/g at TSA process. Also, AC-Mg(Cl) showed the highest initial adsorption amount of 3.848 mmol/g at PSA 0.9 Mpa. When metal impregnated the surface of the activated carbon, it was confirmed that not only physical adsorption, but also chemical adsorption increased, making enhancement in adsorption and desorption performances possible. Also, the prepared adsorbents showed stable adsorption and desorption performances despite repeated processes, confirming their applicability in the TSA and PSA processes.

Biological conversion of CO2 to CH4 in anaerobic fixed bed reactor under continuous operation (혐기성 고정층 생물반응기의 연속운전을 통한 이산화탄소의 메탄전환)

  • Kim, Jaehyung;Koo, Hyemin;Chang, Wonseok;Pak, Daewon
    • Journal of Energy Engineering
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    • v.22 no.4
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    • pp.347-354
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    • 2013
  • This study was carried out to examine different mole ratio of $H_2/CO_2$ and EBCT using the continuous system in the lab scale throughout biological methods with accumulated hydrogenotrophic methanogen that can convert $CO_2$ to $CH_4$. The experimental-based results with various gas mixtures of mole ratio of 4:1($H_2/CO_2$) and 5:1($H_2/CO_2$), $H_2$ was converted more than 99% conversion rate. In case of $CO_2$, 4:1($H_2/CO_2$) and 5:1($H_2/CO_2$) were $74.45{\pm}0.33%$, $95.8{\pm}10.7%$, respectively, in addition, the study was confirmed that the amount of $H_2$ was more needed than stoichiometric equations, where approach methods are empirical versus theoretical frameworks, for converting total $CO_2$. As such, we have noticed that $H_2$ was used for energy source of hydrogenotrophic methanogen for maintaining life. Regarding the results of the ratio of treatment by retention time, limitation of treatment capacity showed that $H_2$(99.9%) and $CO_2$(96.23%) at EBCT 3.3 hrs indicated stable conversion ratio, as well as appeared that methane production rate and $CO_2$ fixation rate were investigated $1.15{\pm}0.02m^3{\cdot}m^{-3}{\cdot}day^{-1}$ and $2.01{\pm}0.04kg{\cdot}m^{-3}{\cdot}day^{-1}$, respectively.

The Effect of Coal Particle Size on Char-$CO_{2}$ Gasification Reactivity by Gas Analysis (가스분석을 이용한 석탄 입자크기가 촤-$CO_{2}$ 가스화 반응성에 미치는 영향 연구)

  • Kim, Yong-Tack;Seo, Dong-Kyun;Hwang, Jung-Ho
    • Korean Chemical Engineering Research
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    • v.49 no.3
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    • pp.372-380
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    • 2011
  • Char gasification is affected by operating conditions such as reaction temperature, reactants gas partial pressure, total system pressure and particle size in addition to chemical composition and physical structure of char. The aim of the present work was to characterize the effect of coal particle size on $CO_{2}$ gasification of chars prepared from two different types of bituminous coals at different reaction temperatures(1,000-$1,400{^{\circ}C}$). Lab scale experiments were carried out at atmospheric pressure in a fixed reactor where heat was supplied into a sample of char particles. When a flow of $CO_{2}$(40 vol%) was delivered into the reactor, the char reacted with $CO_{2}$ and was transformed into CO. Carbon conversion of the char was measured using a real time gas analyzer having NDIR CO/$CO_{2}$ sensor. The results showed that the gasification reactivity increased as the particle size decreased for a given temperature. The sensitivity of the reactivity to particle size became higher as the temperature increases. The size effects became remarkably prominent at higher temperatures and became a little prominent for lower reactivity coal. The particle size and coal type also affected reaction models. The shrinking core model described better for lower reactivity coal, whereas the volume reaction model described better for higher reactivity coal.

Influence of Superplasticizers on Fluidity and Compressive Strength of Alkali Activated Slag Mortar (유동화제가 알칼리 활성 슬래그 모르타르의 유동 특성 및 압축 강도에 미치는 영향)

  • Kim, Dae-Wang;Oh, Sang-Hyuk;Lee, Kwang-Myong
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.1
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    • pp.33-40
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    • 2013
  • The cement industry brought very severe environment problems with massive carbon dioxide during its production. To solve this problem, attempts on Alkali-Activated Slag (AAS) concrete that perfectly substitutes industrial by-products such as ground granulated blast furnace slag (GGBFS) for cement are being actively made. AAS concrete is possible to have high strength development at room temperature, however, it is difficult to ensure the working time due to the fast setting time and the loss of workabillity because of the alkali reaction. In this study, the early age properties of alkali activated slag mortar are investigated to obtain the fundamental data for AAS concrete application to structural members. The water-binder ratio (W/B) was fixed at 0.35 and sodium hydroxide and waterglass as alkali activator was used. The compressive strength, the flow and the ultrasonic pulse velocity were measured according to the type of superplasticisers, which were naphthalene(N), lignin(L), melamine(M) and PC(P), up to a maximum of 2 percent by the mass of GGBFS. The results showed that adding melamine type of superplasticizer improved the fluidity of AAS mortar without decreasing the compressive strength, while naphthalene and polycarbonate type of superplasticizer had little effect on the fluidity of AAS mortar.

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Static Strength of Composite Single-lap Joints Using I-fiber Stitching Process with different Stitching Pattern and Angle (I-fiber Stitching 공법을 적용한 복합재료 Single-lap Joint의 Stitching 패턴과 각도에 따른 정적 강도 연구)

  • Song, Sang-Hoon;Back, Joong-Tak;An, Woo-Jin;Choi, Jin-Ho
    • Composites Research
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    • v.33 no.5
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    • pp.296-301
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    • 2020
  • Laminated composite materials have excellent in-plane properties, but are vulnerable in thickness directions, making it easy to delamination when bending and torsion loads are applied. Thickness directional reinforcement methods of composite materials that delay delamination include Z-pinning, Stitching, Tufting, etc., and typically Z-pinning and Stitching method are commonly used. The Z-pinning is reinforcement method by inserting metal or carbon pin in the thickness direction of prepreg, and the conventional stitching process is a method of reinforcing the mechanical properties in the thickness direction by intersecting the upper and lower fibers on the preform. In this paper, I-fiber stitching method, which complement and improve weakness of Z-pinning and Stitching method, was proposed, and the static strength of composite single-lap joints using I-fiber stitching process were evaluated. The single-lap joints were fabricated by a co-curing method using an autoclave vacuum bag process. The thickness of the composite adherend was fixed, and 5 types of specimens were manufactured with varying the stitching pattern (5×5, 7×7) and angle (0°, 45°). From the test, the failure load of the specimen reinforced by the I-fiber stitching process was increased by up to 143% compared to that of specimen without reinforcement.

Development of a Gliding Arc Plasma Reforming System to Produce Hydrogen Form Biogas (바이오가스 개질을 위한 글라이딩 아크 플라즈마 개질 시스템 개발)

  • Kim, Seong Cheon;Yang, Yoon Cheol;Chun, Young Nam
    • Applied Chemistry for Engineering
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    • v.20 no.4
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    • pp.423-429
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    • 2009
  • The purpose of this study is to investigate the optimal condition for the hydrogen-rich gas production and the CO removal by reforming of gliding arc plasma reforming system using biogas. The parametric screening studies were carried out according to changes of steam feed amount, catalyst bed temperature in water gas reactor and catalyst bed temperature, input air flow rate in preferential oxidation reactor. The standard condition is as follows. The steam/carbon ratio, catalyst bed temperature, total gas flow rate, input electric power and biogas composition rate ($CH_4$ : $CO_2$) were fixed 3, $700^{\circ}C$, 16 L/min, 2.4 kW and 6 : 4, respectively. The results are as follow, HTS optimum operating conditions were S/C ratio of 3 and reactor temperature of $500^{\circ}C$. LTS were S/C ratio of 2.9 and temperature of $300^{\circ}C$. Also, PROX I optimum conditions were input air flow rate of 300 mL/min and reactor temperature of $190^{\circ}C$. PROX II were 200 mL/min and $190^{\circ}C$ respectively. After having passed through each reactor, the results were as follows: 55% of $H_{2}$ yield, 0% of CO selectivity, 99% of $CH_4$ conversion rate, 27% of $CO_2$ conversion rate, respectively.

Study of Oil Palm Biomass Resources (Part 3) - Torrefaction of Oil Palm Biomass - (오일팜 바이오매스의 자원화 연구 III - 오일팜 바이오매스의 반탄화 연구 -)

  • Cho, Hu-Seung;Sung, Yong Joo;Kim, Chul-Hwan;Lee, Gyeong-Seon;Yim, Su-Jin;Nam, Hyeo-Gyeong;Lee, Ji-Young;Kim, Se-Bin
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.46 no.1
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    • pp.18-28
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    • 2014
  • Renewable Portfolio Standards(RPS) is a regulation that requires a renewable energy generated from eco-friendly energy sources such as biomass, wind, solar, and geothermal. The RPS mechanism generally is an obligatory policy that places on electricity supply companies to produce a designated fraction of their electricity from renewable energies. The domestic companies to supply electricity largely rely on wood pellets in order to implement the RPS in spite of undesirable situation of lack of wood resources in Korea. This means that the electricity supply companies in Korea must explore new biomass as an alternative to wood. Palm kernel shell (PKS) and empty fruit bunch (EFB) as oil palm wastes can be used as raw materials used for making pellets after their thermochemical treatment like torrefaction. Torrefaction is a pretreatment process which serves to improve the properties including heating value and energy densification of these oil palm wastes through a mild pyrolysis at temperature typically ranging between 200 and $300^{\circ}C$ in the absence of oxygen under atmospheric pressure. Torrefaction of oil palms wastes at above $200^{\circ}C$ contributed to the increase of fixed carbon with the decrease of volatile matters, leading to the improvement of their calorific values over 20.9 MJ/kg (=5,000 kcal/kg) up to 25.1 MJ/kg (=6,000 kcal/kg). In particular, EFB sensitively responded to torrefaction because of its physical properties like fiber bundles, compared to PKS and hardwood chips. In conclusion, torrefaction treatment of PKS and EFB can greatly contribute to the implement of RPS of the electricity supply companies in Korea through the increased co-firing biomass with coal.