• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.616-620
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• 2013

In this work, the combustive properties of the swine manure, poultry manure, and mixtures based on the resource recycling-energy were investigated. After the specimens were dried to a constant weight by dry oven, combustive properties were tested by the cone calorimeter (ISO 5660-1). It was found that the peak effective heat of combustion (PEHC) in the swine manure (78.72 MJ/kg) has risen due to more amount of the hydrocabon compared with poultry manure (69.41 MJ/kg), also the swine manure increased both of the higher $CO_2$ production rate (0.1959 g/s) and total smoke release rate (THRR) ($419m^2/m^2$) than those of the poultry manure. However, both of the CO production release (0.0996 kg/kg) and CO production rate (0034 g/s) in the poultry manure increased due to more amount of the inorganic contents compared with swine manure. Thus, the high combustion energy is expected to generate depend on the hydrocarbon content.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.949-955
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• 2000

Numerical study with detailed chemistry has been conducted to investigate the NOx formation and structure in $CH_4/Air-CO_2$ counterflow diffusion flames. The importance of radiation effect is identified and the role of $CO_2$ addition is addressed to thermal and chemical reaction effects, which can be precisely specified through the introduction of an imaginary species. Also NO separation technique is utilized to distinguish the contribution of thermal and prompt NO formation mechanisms. The results are as follows : The radiation effect is dominant at low strain rates and it is intensified by $CO_2$ addition. Thermal effect mainly contributes to the changes in flame structure and the amount of NO formation but the chemical reaction effect also cannot be neglected. It is noted that flame structure is changed considerably due to the addition of $CO_2$ in such a manner that the path of methane oxidation prefers to take $CH_4 {\rightarrow}CH_3{\rightarrow}C_2H_6{\rightarrow}C_2H_5$ instead of $CH_4 {\rightarrow}CH_3{\rightarrow}CH_2{\rightarrow}CH$. At low strain rate(a=10) the reduction of thermal NO is dominant with respect to reduction rate, but that of prompt NO is dominant with respect to total amount.

• Korean Journal of Animal Reproduction
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• v.19 no.4
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• pp.259-264
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• 1996

This study was carried out to investigate on the survival rates and in vitro developmental rates of bisected bovine embryos were by manipulator and micropipette. Bisected embryos were co-cultured in 20% FCS(v/v)＋TCM-199 media containing hormones, oviductal epithelial cells and cumulus cells 0 to 72 hrs after bisection. Survival rate and in vitro fertilization rate were defined as development rate on in vitro culture or FDA-test. The results are summarized as follows ; 1. The in vitro developmental rate of biseciton embryos co-cultured in 20% FCS＋TCM-199 medium containing PMSG, hCG, PMSG＋hCG, hCG＋$\beta$-estradiol 0 to 20 hrs and 20 to 40 hrs were 36.7, 26.7, 33.3, 40.0, and 30.0, and 30.0, 33.3, 30.0, 26.7, and 26.7%, respectively. The survival rate of bisection embryos co-cultured in TCM-199 medium containing hormones was significantly higher than that of non co-culture(25.0%). 2. The in vitro developmental rates of bisection embryos co-cultured in 20% FCS＋TCM-199 medium containing oviductal epithelial cells 4 to 5 hrs and 20 to 24 hrs were 40.0 and 33.3%, respectively. The survival rate of bisection embryos co-cultured in TCM-199 medium containing oviductal epithelial cells was significantly higher than that of non co-culture(25.0%). 3. The in vitro developmental rates of bisection embryos co-cultured in 20% FCS＋TCM-199 medium containing cumulus cells 4 to 5 hrs and 20 to 24 hrs were 43.3 and 36.7%, respectively. The survival rate of bisection embryos co-cultured in TCM-199 medium containing cumulus cells was significantly higher than that of non co-culture (25.0%).

• Membrane and Water Treatment
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• v.10 no.2
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• pp.127-137
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• 2019

The D2EHPA/TBP co-extractants immobilized PolyHIPE membrane can be used for the selective separation of Mn (II) from Co (II). By solvent-nonsolvent method, D2EHPA/TBP co-extractants can be effectively immobilized into PolyHIPE membrane. The pore structure of PolyHIPE membrane and the presence of TBP enhance the stability of immobilized co-extractants. The optimal operating conditions for the separation of Mn (II) and Co (II) are feeding phase at pH 5.5, sulfuric acid concentration in the stripping phase of about 50 g/L and stirring speed at 400 rpm. The D2EHPA/TBP co-extractants ratio of 5:1 shows synergetic effect on Mn/Co separation factor about 22.74. The removal rate and recovery rate of Mn (II) is about 98.4 and 97.1%, respectively, while for Co (II) the transport efficiency is insignificant. The kinetic study of Mn (II) transport shows that high initial flux, $J_f^o=80.1({\mu}mol/m^2s)$, and maxima stripping flux, $J_s^{max}=20.8({\mu}mol/m^2s)$, can be achieved with D2EHPA/TBP co-extractants immobilized PolyHIPE membrane. The stability and reusability study shows that the membrane can maintain a long term performance with high efficiency. High purity of Co (II) and Mn (II) can be recovered from the feeding phase and stripping phase, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.21-27
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• 2016

Global warming due to greenhouse gas emissions is considered as a major problem worldwide, and many countries are making great efforts to reduce carbon dioxide emissions. Many technologies in post-combustion, pre-combustion and oxy-fuel combustion $CO_2$ capture have been developed. Among them, a hybrid pre-combustion $CO_2$ capture system of a water gas shift (WGS) reactor and a membrane gas separation unit was investigated. The 2 stage WGS reactor integrated high temperature shift (HTS) with a low temperature shift (LTS) was used to obtain a higher CO conversion rate. A Pd/Cu dense metal membrane was used to separate $H_2$ from $CO_2$ selectively. The performance of the hybrid system in terms of CO conversion and $H_2$ separation was evaluated using a 65% CO, 30 % $H_2$ and 5% $CO_2$ gas mixture for applications to pre-combustion $CO_2$ capture. The experiments were carried out over the range of WGS temperatures ($200-400^{\circ}C$), WGS pressures (0-20bar), Steam/Carbon (S/C) ratios (2.5-5) in a feed gas flow rate of 1 L/min. A very high CO conversion rate of 99.5% was achieved with the HTS-LTS 2 stage water gas shift reactor, and 83% $CO_2$ was concentrated in the retentate using the Pd/Cu membrane.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.156-159
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• 2010

Peroxide is used frequently to provide electron acceptors to aerobes for the purpose of in situ bioremediation of contaminated soil/sediment. In this study, oxygen release rate of peroxides and factors affecting on dissolution and diffusion of oxygen into pore water were evaluated. Peroxides studied in this study were magnesium peroxide ($MgO_2$), calcium peroxide ($CaO_2$), and sodium percarbonate ($Na_2CO_3{\cdot}1.5H_2O_2$). $Na_2CO_3{\cdot}1.5H_2O_2$ showed the highest oxygen release rate per unit mass and the shortest release duration time among three peroxides. A simple first-order decay model for predicting the release rate of oxygen from peroxide into pore water was presented and used to fit the experimental data. The first order oxygen release rate constants k for $MgO_2$, $CaO_2$ and $Na_2CO_3{\cdot}1.5H_2O_2$ were 0.45 /hr, 3.22 /hr and 134 /hr, respectively. If $MgO_2$ was mixed with clay, oxygen release rate was lowered significantly mainly due to limitation of contact area and diffusion, implying that oxygen can be provided to the indigenous aerobes for the extended period of time.

• Journal of Hydrogen and New Energy
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• v.20 no.3
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• pp.245-255
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• 2009

Effect of CO$_2$ concentration on reduction reactivity of oxygen carrier particles for chemical-looping combustor were investigated. Four particles, NiO/bentonite, OCN601-650, OCN702-1100, OCN702-1250, were used as oxygen carrier particles and two kinds of gases (CH$_4$, 5%, N$_2$ balance and CH$_4$ 5%, CO$_2$ balance) were used as reactants for reduction. For all oxygen carrier particles, higher maximum conversion, reduction rate, oxygen transfer capacity, and oxygen transfer rate were achieved when we used N$_2$ balance gas. OCN601-650 particle showed higher oxygen transfer rate for all gases than other particles, and therefore we selected OCN601-650 particle as the best candidate. For all particles, lower carbon depositions were observed when we used CO$_2$ balance gas.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.241-242
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• 2006

In this work, the $LiFePO_4-LiCoO_2$ mixed cathode electrodes were prepared and their electrochemical performances were measured in different current density. The cell of $LiFePO_4-LiCoO_2$ observed two voltage plateau regions at 3.4 and 3.9V. The cell of $LiFePO_4-LiCoO_2$ (90:10 wt%) mixed cathode delivered a discharge capacity of ca. 139.8 mAh/g at a 0.2C rate. The capacity of the cell decreased with the current rate and a useful capacity of ca 85.7mAh/g was obtained at a 2C rate.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.6
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• pp.526-530
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• 1994

This study was conducted to investigate photosynthetic response to four sequential air influx rate with rice(Oryza sativa L.)plants moved from a natural condition to constant condition with automatic regulation selected environmental variables on 13th~15th days after anthesis. In time course of photosynthetic response to increasing air influx rate(200-280-360-440 ml / min.), stomatal conductance decreased rapidly at the beginning after treatment and then oscillated with a free-running period of a approximately 1 hour to 1 hour 30 minutes until reached up to steady-state condition. Similar change was also observed $CO_2$ assimilation rate. Stomatal conductance decreased throughout the air influx rate sequence, but the rate of decrease was similar to the decrease in $CO_2$ assimilation rate observed under continuous air influx rate conditions. In starch granules during grain filling period under air influx rate(440 ml / min.) , compound starch granules were loosing and a number of hollows were observed in surface of single starch granules. Evidences from several approaches indicate that synchronization of stomatal conductance and$CO_2$ assimilation rate was closely inter-related tinder increase of air influx rate and increase of air influx rate influenced the$CO_2$ uptake in photosynthetic processes and compound starch granule, as 'end products' of photosynthesis.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.470-474
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• 2008

The whole berry, pulp, and seed of sea buckthorn fruit were extracted with supercritical $CO_2$ to produce edible oils. The effects of extraction pressure, temperature, and $CO_2$ flow rate on the oil yield and extraction rate were investigated, and the fatty acid composition, tocopherol, and carotenoid contents of the oils were compared. The results showed that the extraction rate was affected by pressure, temperature, and $CO_2$ flow rate and, in general, the yield increased with a rise in any of the 3 variables. Fatty acids in the whole berry and pulp oil were dominated by monounsaturated fatty acids (>64%), followed by saturated fatty acids (about 30%). In contrast, fatty acids in the seed oil consisted mainly of polyunsaturated (>60%) and monounsaturated fatty acids (>24%). The seed oil had a slightly higher content of tocopherols, but a much lower content of carotenoids, compared with the whole berry or pulp oil.