• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.447-453
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• 2004

Optimal conditions for the supercritical carbon dioxide $(scCO_{2})$ extraction of glycyr­rhizin from licorice (Glycyrrhiza glabra) were investigated, with an emphasis on the types and levels of modifiers. The morphology of the licorice tissue remaining after the $scCO_{2} $ extraction of glycyrrhizin was examined by scanning electron microscopy, coupled with measurements of ab­solute density. Conventional organic solvent extraction was also carried out for purpose of quantitative comparison. At 50 MPa and $60^{circ}C$ glycyrrhizin could not be extracted with pure $scCO_{2}$, while a considerable amount of glycyrrhizin was extracted when water was added to $scCO_{2}$ as a modifier. The highest recovery was found to be about $97\%$ when $70\%$ aqueous methanol was added to $scCO_{2}$ at a concentration of $15\%$. The optimal pressure and temperature for the supercritical fluid extraction of glycyrrhizin were observed to be 30 M Pa and $60^{circ}C$, respectively. Under these conditions, the percentage recovery of glycyrrhizin attained a maximum value of 102.67\pm$ $1.13\%$ within 60 min. Furthermore, in the case of $scCO_{2}$ modified with $70\%$ aqueous methanol, the licorice tissue obtained after extraction was found to be severely de­graded by excessive swelling, and the absolute density of the licorice residues was observed to be the highest.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.206.1-206.1
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• 2010

폐기물 등을 열분해 가스화한 합성가스로부터 효과적으로 고순도의 수소를 회수하기 위하여 WGS(수성가스전환반응) 및 $CO_2$ 회수 PSA 공정을 적용하였다. 벤치스케일 열교환형 WGS반응기를 개발하여 기존 단열방식에 비하여 단순화한 반응시스템을 구축하였으며 출구 CO농도 4%대를 달성하였다. 또한 3베드로 구성된 벤치스케일의 $CO_2$ PSA운전을 수행한 결과, 2.5barg 흡착 및 진공재생단계를 적용하여 회수되는 $CO_2$의 농도가 95%이상, 회수율 80%이상을 기록하는 효율적인 $CO_2$ 회수공정을 개발하였다. 한편, 흡탈착 모사프로그램인 ADSIM을 통해서도 실험과 비교적 일치한 결과를 얻을 수 있었는데 향후 스케일업 설계자료 확보시 유용할 것으로 판단되었다.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.624-628
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• 1998

The aromatic organic solvents(BTX) were decomposed in the fixed bed reactor packed with a 0.5% $Pt/{\gamma}-Al_2O_3$ catalyst, then, supercritical carbon dioxide(SC-$CO_2$) was used as the reaction media. And the conversion was dependent on the inlet concentration of BTX and the molar density of SC-$CO_2$. The conversion of BTX was decreased with increasing of inlet concentration, and was increased with temperature and pressure. The maximum conversion of benzene was 98.5% at $300^{\circ}C$ and 204.1 atm, and that of toluene and xylene were 82.0 and 76.5%, respectively, at $350^{\circ}C$ and 204.1 atm. The intermediate products of partial oxidation were identified as benzaldehyde, phenol, benzenemethanol, and so on. The BTX can be effectively converted into harmless $CO_2$ and $H_2O$ at appropriate operating condition. Thus, the nontoxic recovery process was suggested as the removal method of BTX.

• Geophysics and Geophysical Exploration
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• v.19 no.1
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• pp.37-44
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• 2016

$CO_2$-EOR (Carbon Dioxide-Enhanced Oil Recovery), one of the enhanced oil recovery methods, helps to not only enhance the production of oil, but also store carbon dioxide in underground. However, if micro fractures occur when during the injection of $CO_2$, it is difficult to make permanent storage of $CO_2$ in reservoir and can cause contamination of groundwater and soil. Therefore, in this study, we performed microseismic monitoring to investigate the occurrence of fractures during the $CO_2$ injection at the Meruap oil reservoir, Indonesia. To pick the first arrivals of microseismic events, Improved MER (Modified Energy Ratio) method was used. After picking the first arrivals, hodogram analysis was carried out by using the data recorded at three component geophones to calculate the back azimuth of events. Finally, locations of microseismic events were decided by using the results of first arrival picking and hodogram analysis. Estimated locations showed that all microseismic events were occurred at surface and any fracture did not occur around the reservoir. Moreover, by analyzing noise characteristic, we confirmed that almost of picked first arrivals were due to the repetitive mechanical noise.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.403-412
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• 2018

Recently, needs for utilization of recycled aggregate have been increasing. However, its utilization has been limited due to its high alkalinity, which mostly came from the unremoved cement paste particles that were attached at the surface of recycled aggregate. Various efforts has been made to reduce its alkalinity by using $CO_2$, but currently available methods that uses $CO_2$ generate the problem with pH recovery. Considering the fact that supercritical $CO_2$ ($scCO_2$) can provide more rapid carbonation of cement paste than by normal $CO_2$, $scCO_2$ was utilized in this work. The reaction between $scCO_2$ and hydrated cement paste has been systematically evaluated. According to the results, it was found that powder type showed higher carbonation compared to that of cube specimens. It seems the carbonation by $scCO_2$ has occurred only at the surface of the specimen, and therefore still showed some amount of $Ca(OH)_2$ calcium aluminates after reaction with $scCO_2$. With powder type specimen, all $Ca(OH)_2$ was converted into $CaCO_3$. Moreover, additional calcium that came from both calcium aluminate hydrates and calcium silicate hydrates reacted with $scCO_2$ to form $CaCO_3$. After carbonation with $scCO_2$, the powder type specimen did not show pH recovery, but cube specimens did show due to the presence of portlandite.

• ETRI Journal
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• v.34 no.1
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• pp.35-43
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• 2012

This paper presents a delay-locked-loop-based clock and data recovery (CDR) circuit design with a nB(n+2)B data formatting scheme for a high-speed serial display interface. The nB(n+2)B data is formatted by inserting a '01' clock information pattern in every piece of N-bit data. The proposed CDR recovers clock and data in 1:10 demultiplexed form without an external reference clock. To validate the feasibility of the scheme, a 1.7-Gbps CDR based on the proposed scheme is designed, simulated, and fabricated. Input data patterns were formatted as 10B12B for a high-performance display interface. The proposed CDR consumes approximately 8 mA under a 3.3-V power supply using a 0.35-${\mu}m$ CMOS process and the measured peak-to-peak jitter of the recovered clock is 44 ps.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.91-96
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• 2018

This study is collects design data through the process design of the organic Rankine cycle, which can produce 20kW of electric power through the recovery of waste heat. In this study, the simulation was conducted by using APSEN HYSYS in order to make the model for the process design of the 20kW class waste heat recovery system. For the thermodynamic model, the test was conducted with hot water as the heat source, with the water steam used as the cooling water for the cooler and the refrigerant R245fa in the cycle. In Case 1 and Case 2, it was expected and found that the cycle efficiency was 10.6% and that 36.86kw was produced, considering the margin of 84% of 20kW. In Case 3 and Case 4, it was expected and found from the simulation that the cycle efficiency was 12% and that 30.0kw was produced, considering the margin of 84% of 20kW.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.328-330
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• 2009

1 kW class Polymer Electrolyte Fuel Cell(PEFC) co-generation systems have been developed from 2001 and evaluated for improvement of efficiency, durability and reliability of the system. This paper introduce new version system including with excellent reliability, durability and user friendly applications. Its electrical and overall efficiency showed 35 % and 80 %, respectively, and noise level of the system was less than 45 dB. In addition, this system have various functions such as load change, $N_2$ less purge, low emission and low temperature operation ($-15^{\circ}C$) through development of operation logic. This system was designed for convenient installation in indoor and outdoor due to the compactness of size and the separation of electrical and heat recovery units, which means a user can select the size of heat recovery unit.

• Biomolecules & Therapeutics
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• v.8 no.3
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• pp.213-216
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• 2000

In vivo administration of Leucostim, a human recombinant granulocyte colony-stimulating factor (G-CSF), was evaluated for the effects on survival, hematologic recovery, and colony forming unit- spleen (CFU-5) in murine bone marrow transplantation (BMT) model. Sublethally irradiated (9 Gy) mice received bone marrow cells from untreated mice, and then were treated with G-CSF subcutaneously at doses of 2.5,5, or $10\mu\textrm{g}$/kg or vehicle solution (control) for 14 days from one day after BMT. There was no effect of irradiation and BMT on mortality. The repeated subcutaneous injections of Leucostim for 14 days post- BMT significantly facilitated hematologic recovery compared with vehicle control in a dose-dependent manner. Moreover, mice treated with Leucostim had significantly increased numbers of CFU-s colonies on day 10 post-BMT. These results suggest that Leucostim, a new G-CSF, has beneficial effects on hematologic reconstitution after BMT.

• Resources Recycling
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• v.22 no.6
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• pp.3-11
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• 2013

This study was carried out to estimate greenhouse gas reduction potentials under treatment methods of combustible wastes excavated from closed landfill. The treatment methods of solid wastes were landfilling, incineration, and production of solid recovery fuel. The greenhouse gas reduction potentials were calculated using the default emission factor presented by IPCC G/L method of IPCC (Intergovernmental Panel on Climate Change). The composition of excavated waste represented that screened soil was the highest (65.96%), followed by vinyl/plastic (19.18%). This means its own component is similar to the other excavated waste from unsanitary landfill sites. Additionally, its bulk density was 0.74 $t/m^3$. In case of landfilling of excavated waste, greenhouse gas emission quantity was 60,542 $tCO_2$. In case of incineration of excavated waste, greenhouse gas emission quantity was 9,933 $tCO_2$. However, solid recovery fuel from excavated waste reduced 33,738 $tCO_2$ of the greenhouse gas emission quantity. Therefore, solid recovery fuel production is helpful to reduce of greenhouse gas emission.