• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.187-193
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• 2010

In this study we have designed and fabricated an inexpensive micro electronic system that we call Alvitek. It can indirectly but accurately predict and display the partial pressures of alveolar oxygen and carbon dioxide for the patients in the ICU of a hospital. Alvitek consists of both hardware part and software part. Performance of the system is tested by animal experiment with pigs for various $F_{t}e_{2}$ and RR(Respiratory Rate) values under the mechanical ventilation. The predicted alveolar gas partial pressures are cprpared with the approximate alveolar oxygen partial pressures easily calculated by the physician’s bedside formula. As a result, we have concluded that the relative error of A-$aDe_2$ calculated by the bedside formula grows seriously for lower $F_{t}e_{2}$ values. The present prediction method of Alvitek is henceforth believed very meaningful to the physicians. The system hardware and software are described in the text.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.4
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• pp.290-295
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• 1994

Soil $CO_2$ evolution was measured using the soda-lime method for 20-year-old L. tulipifera, P. albaglandulosa, and Q. rubra plantations planted on a similar soil type in the Kwangneung Experimental Forest during the growing season of 1994. Soil $CO_2$ evolution ranged from $0.21g/m^2/hr$ for Q. rubra to $0.33g/m^2/hr$ for L. tulipifera. and was significantly different among species. We found positive correlations between soil $CO_2$ evolution and air(p<0.001, r=0.39) and soil temperatures(p<0.001, r=0.49). Peaks in seasonal soil $CO_2$ evolution occurred in July and August. Seasonal soil $CO_2$evolution did not necessarily follow changes in air and soil temperatures. This study implies that more work is needed to clarify the influence of other factors on soil $CO_2$evolution.

• Food Science and Preservation
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• v.10 no.1
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• pp.6-10
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• 2003

The objective of this study was to investigate the effect of browning inhibitor and vacuum packaging on minimally processed sweet pumpkin. The browning inhibitor were lo/e of ascorbic acid, citric acid, NaCl, MgCl$_2$and their combination. For the minimal processing, sweet pumpkin was sliced and strip-cut followed by dipping in the solution of browning inhibitor. Effective browning inhibitors fer slice sweet pumpkin were ascorbic acid, NaCl and MgC1$_2$, and those fer thin strip were combination and ascorbic acid. The hardness of minimally processed sweet-pumpkin repeated increasing and decreasing and decreased in the final of storage. However the change pattern of hardness was different according to cutting method. Magnesium chloride treatment was generally high grade on sensory characteristics. Sweet pumpkin treated with citric acid was distinguished on carbon dioxide generation and oxygen exhaustion.

• Food Science and Preservation
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• v.13 no.3
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• pp.363-368
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• 2006

This study was performed to develop flavor materials from Elsholtzia ciliata Hylander with analyzing functionality and aroma profile and to optimize supercritical fluid extraction method and optimum condition. The qualities of water extracts such as total yield total phenolic compound electron donation ability, estragole and L-carvone, were affected by extraction pressure than time. The response variables had significant with pressure than with time and the established polynomial model was suitable(P>0.05) model by Lack-of-Fit analysis. The optimum extraction conditions which were limited of maximum value for dependent variables under experimental conditions based on central composite design were 238 bar and 42 min.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.567-570
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• 2008

The present study investigated the applicability of the minium fludization velocity measuring method using linear regression analysis between the standard deviation of pressure fluctuation and gas velocity in multi-particle sand on a fluidized bed 0.109 in inner diameter. We measured minium fludization velocity according to the standard deviation of particle distribution in Gaussian distribution. The measured value compared with other researchers' equations. The minium fludization velocity derived from the linear regression analysis of the standard deviation of pressure fluctuation and pressure drop inside the bed. We also found that the minium fludization velocity of a multi-particle system using the standard deviation of pressure fluctuation must be measured at freely bubbling region.

• KSBB Journal
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• v.14 no.6
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• pp.742-746
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• 1999

The microalgal, Chlorella sp. HA-1, had good $CO_2$ fixation efficiency compared to other algal strains at the same operating condition. In this study, Chorella sp. HA-1 showed similar tolerance both 10% and 20% $CO_2$ concentration. By optimization of the major operation variables such as pH, initial cell concentration, light intensity, the $CO_2$ fixation rate could be raised to a reasonably high value, 372 $gCO_2/m^2{\cdot}day$ in a 3 L internally illuminated photobioreactor. In order to maintain the $CO_2$ fixation rate for a long time, the method of semi-continuous operation was employed, in which dilution ratio was the controlling parameter. Starting with the dilution ratio of 0.5 with the increased increment of 0.1, the constant $CO_2$ fixation rate was obtained.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.2
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• pp.137-142
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• 2013

The indiscriminate use of the fossil fuel has caused serious environmental pollutions such as the shortage of energy and global warming. Microalgae have being emphasized as $3^{rd}$ generation biomass which makes the carbon dioxide reduce effectively as well as produces the biofuel. Large scale production of microbial biomass by continuous culture is a quite challenging issue, because off-line optimization strategies of a microbial process utilizing a model-based scheme give rise to many difficult problems. In this paper, the static and simple control method which was able to be applied in time-variant growth environment and large scale of algae culture was studied. The significant disturbances in on-line measurement of cell density were reduced by Savitzky-Golay FIR smoothing filter. Dunaliella salina was cultivated continuously in a flat panel photobioreactor by the on-off control of the turbidostat process.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2349-2356
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• 2014

The recycling technology by the catalytic conversion is one of the most promising techniques for the $CO_2$ treatment of coal burning power plant flue gases. The conversion of $CO_2$ to valuable product of $CH_4$ can be used as a fuel to run the turbine for electricity generation. Through this technique, the amount of coal needed for the combustion in a gas turbine can be reduced as well as $CO_2$ emissions. Therefore, a series of catalysts based on cerium oxide doped with copper, nickel and manganese were prepared by impregnation method. From the characterization analysis, it showed that the prepared catalysts calcined at $400^{\circ}C$ were amorphous in structure with small particle size in the range below 100 nm. Meanwhile, the catalyst particles were aggregated and agglomerated with higher surface area of $286.70m^2g^{-1}$. By increasing the calcination temperature of catalysts to $1000^{\circ}C$, the particle sizes were getting bigger (> 100 nm) and having moderate crystallinity with lower surface area ($67.90m^2g^{-1}$). From the catalytic testing among all the prepared catalysts, Mn/Ce-75/$Al_2O_3$ calcined at $400^{\circ}C$ was assigned as the most potential catalyst which gave 49.05% and 56.79% $CO_2$ conversion at reaction temperature of $100^{\circ}C$ and $200^{\circ}C$, respectively.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.319-319
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• 2017

Methane is the main greenhouse gas released from rice paddy field. Methane from paddy fields accounts for 11 % of the global total methane emission. The global warming potential (GWP) of methane is 25 times more than that of carbon dioxide on a mass basis. It is well known that most effective practice to mitigate methane in paddy is related to the water management during rice growing season and the use of organic matters. This study was conducted to investigate the effects of tillage and cultivation method on methane emission in paddy. Tillage (tillage and no-tillage) and cultivation methods (transplanting and direct seeding) were combined tillage-transplanting (T-T), tillage-wet hill seeding (T-W), tillage-dry seeding (T-D) and no-till dry seeding (NT-D) to evaluate methane mitigation efficiency. Daily methane emission was decreased on seeding treatments (T-W, T-D, NT-D) than transplanting treatment (T-T). Amount of methane emission during rice growing season is highest in T-T ($411.7CH_4\;kg\;ha^{-1}y^{-1}$) and lowest in NT-D treatment (89.7). In T-W and T-D treatments, methane emissions were significantly decreased by 36 and 51 % respectively compared with T-T. Methane emissions were highly correlated with the dry weight of whole rice plant ($R^2=0.62{\sim}0.93$). T-T treatment showed highest $R^2$ (0.93) among the four treatments. Rice grain yields did not significantly differ with the tillage and cultivation methods used. These results suggest that direct seeding practice in rice production could mitigate the methane emissions without loss in grain yield.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.4
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• pp.583-591
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• 2015

The coastal stow net (stow net hereafter) in Korea is one of the major fishing methods for yellow croaker (Larimichthys polyactis), ribbon fish (Trichiurus lepturus), and anchovy (Engraulis japonicus). In terms of energy efficiency, the stow net fishery is more competitive than towing fishing gears such as trawl gears. The fishing vessels in stow net fishery have consumed less fossil fuel and also have had less carbon dioxide emission into the atmosphere. however, the stow net fishery is necessary to be regulated due to its increased output of the fleet. Therefore, it is required for fisheries authorities to manage the fishing capacity or fishing power for the assurance of fishery's sustainability. For fisheries management authorities, it is necessary to quantify data related to fishing capacity and fishing power to deploy fishery policy in a sustainable way. In terms of data for decision-making, Data envelopment analysis (DEA) method was conducted to estimate fishing capacity. Fishing power index (FPI) was also applied to calculate relative fishing power to approach the problem in a quantitative way.