• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.151-159
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• 2015

Paper records were generally degraded by some factors from atmospheric environments, like temperature, relative humidity or air pollutants. In this study, the degradation behavior of paper records by single or mixed gases of $NO_2$, $SO_2$, HCHO and TVOC was evaluated. The mechanical, optical and chemical properties of 4 kinds of paper (acid and neutral-based printing paper, traditional Hanji, and filter paper) were directly and indirectly affected by gaseous harmful materials. The brightness and $L^*$ value in all papers were slightly increased by accelerated aging under gaseous HCHO and TVOCs, but highly decreased by conditions under gases $NO_2$ and $SO_2$. The optical properties of paper records were most vulnerable in acid-based paper and high stable in filter paper and traditional Hanji by air pollutant degradation. The aging treatments under mixed gas pollutants including $NO_2$ resulted in decrease of physical, mechanical and optical properties of paper, so it was supposed that the concentration of $NO_2$ gas would be strictly controlled for optimum indoor air quality management in domestic storage centers for paper records.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.2
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• pp.225-241
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• 2007

A closed flux chamber system was used for measuring major greenhouse gas (GHG) emission from tideland and/or wetland soils in estuarine area at Saemankum, Kunsan in southwestern Korea during from months of February to June 2006. Hourly averaged GHG soil emissions were measured two to three times a day during the ebb tide hours only. Site soils were analyzed for soil parameters (temperature, pH, total organic contents, N and C contents in soil) in the laboratory. Soil GHG fluxes were calculated based on the GHG concentration rate of change measured inside a closed chamber The analysis of GHG was conducted by using a Gas Chromatography (equipped with ECD/FID) at laboratory. Changes of daily, monthly GHGs' fluxes were examined. The relationships between the GHG emissions and soil chemical contents were also scrutinized with respect to gas production and consumption mechanism in the soil. Soil pH was pH $7.47{\pm}0.49$ in average over the experimental period. Organic matter contents in sample soil was $6.64{\pm}4.98\;g/kg$, and it shows relatively lower contents than those in agricultural soils in Kunsan area. Resulting from the soil chemistry data, soil nitrogen contents seem to affect GHG emission from the tidal land surface. The tidal soil was found to be either source or sink for the major GHG during the experimental periods. The annual average of $CH_{4}\;and\;CO_{2}$ fluxes were $0.13{\pm}0.86\;mg\;m^{-2}h^{-1}\;and\;5.83{\pm}138.73\;mg\;m^{-2}h^{-1}$, respectively, which will be as a source of these gases. However, $N_{2}O$ emission showed in negative flux, and the value was $-0.02{\pm}0.66\;mg\;m^{-2}h^{-1}$, and it implies tidal land surface act as a sink of $N_{2}O$. Over the experimental period, the absolute values of gas fluxes increased with soil temperature in general. Averages of the ambient gas concentration were $86.8{\pm}6.\;ppm$ in $CO_{2},\;1.63{\pm}0.34\;ppm\;in\;CH_{4},\;and\;0.59{\pm}0.15\;ppm\;in\;N_{2}O$, respectively. Generally, under the presence of gas emission from agricultural soils, decrease of gas emission will be observed as increase in ambient gas concentration. We, however, could not found significant correlation between the ambient concentrations and their emissions over the experimental period. There was no GHG compensation points existed in tide flat soil.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.169-172
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• 2005

We present CO(3-2), CO(2-1), and 230 GHz (1.3 mm) continuum images of nearby galaxies taken with the Submillimeter Array (SMA). Our main topic is to study the relation between higher-J molecular gas (e.g., CO J=3-2, 2-1) and nuclear activities (e.g., active galactic nuclei [AGNs] and starbursts). The nearby Seyfert 2 galaxy M51 shows strong CO(3-2) emission from the circumnuclear molecular gas, with an intensity twice as strong as that of the CO(1-0) emission. Strong CO(3-2) emission enhancement suggests that the circum nuclear molecular gas in M51 is warm and dense, which may be related to the AGN activities. Molecular gas in the nearby moderate starburst galaxy NGC 6946 is distributed along the large-scale bar or spiral arms and along the minibar, and the multi-J CO line images show very similar distribution to each other. For this galaxy, there is no clear enhancement in higher-J lines as seen in M51, which may be because NGC 6946 does not have clear AGN activities. Based on the results of these two galaxies, the physical conditions of the circum nuclear molecular gas may be related to the AGN activities. We also observed the nearby edge-on starburst galaxy NGC 3628 and the starburst/Seyfert composite galaxy NGC 4945 with the CO(2-1) line and 230 GHz (1.3 mm) continuum emission. These information will give us some hints for understanding the relation between nuclear activities and circum nuclear molecular gas and dust.

• Journal of the Korean Chemical Society
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• v.29 no.1
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• pp.52-60
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• 1985

Oxides of nitrogen (NO$_x$) in exhaust gases was determined by absorbing the gas in alkaline peroxide solution containing 0.03${\%}$ H2O2 and 0.1N NaOH. About 100 ppm of NO$_x$ was rapidly oxidized to NO$_2$ or N$_2$O$_5$ by H$_2$O$_2$ and required a contact time of 2 minutes with the absorbing solution for complete absorption. With vigorous shaking including air or oxygen gas, high concentration of NO$_x$ (>200 ppm) can be absorbed within 30 minutes. The remaining H$_2$O$_2$ affect the absorbance of color solution strongly. However, the excess H$_2$O$_2$ was completely decomposed by zinc powder 0.5g and the sample solution should be adjusted to the pH range 6.1∼6.6 before the reduction so that conversion of nitrate to nitrite ion is possible. The absorbed NO$_x$ is determined colorimetrically by the diazotization-coupling method with sulfonilamide and NEDA as the coupling agent. The sensitivity of the new method was 4.48 ${\times}$ 10$^4$ as molar absorptivity which was high sensitive compared with that obtained for the usual zinc reduction NEDA method with O$_3$. This method was far more rapid, brief and accurate than previously published O$_3$-NEDA method in Korean industrial standard.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.1
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• pp.145-153
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• 1987

Stability limits of a double concentric jets flame and the structure of recirculation zone formed behind a thick burner rim were investigated. To control the flame stability, swirled secondary air flow ranging 0.13-0.71 of swirl number, and air, fuel, and mixture gas injection from an injection coaxial slit set on burner rim were examined. Flame stability limits, flame shapes, lengths of recirculation zone, temperature distributions, residence times, air ratios in the recirculation zone were measured. The following results were obtained. (1) Lean limits were considerably widened by a strong swirl because the recirculation zone was enlarged. (2) At fuel injection as well as mixture injection, lean limits were also extended. But, air injection had no effect on stability limits. (3) Injected gas seems to diffuse into the recirculation zone through its outer boundary surrounded the secondary air. Therefore, chemical structure in the recirculation zone with air injection coincides with that without injection. (4) Injection position had no effect on flame stability limits.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.203-206
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• 2006

The sensor consists of a heater, an insulating layer, a pair of contact electrodes, and CNT-sensing film on a micromachined diaphragm. The heater plays a role in the temperature change to modify sensor operation. Gas sensor responses of CNT-film to $NO_2$ at room temperature are reported. The sensor exhibits a reversible response with a time constant of a few minutes at thermal treatment temperature of $130^{\circ}C$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3246-3252
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• 2009

The interest on the recovery of thermal energy using the waste has been rising to solve the problems of continuous increase of waste generation and the depletion of the fossil fuel recently. The incineration has been used most popularly as a treatment process of the waste for the energy recovery. However, it is expected that incineration and design cost will increase in the treatment of air contaminant emitted from incinerator. This research has simulated the actual incinerator and the flue gas treatment system using the Aspen plus which is the software to simulate the chemical process. The incineration process is composed of the 1st and 2nd combustor to burn the waste, SNCR process to reduce the $NO_x$ using the urea, and the steam generation process to save the energy during incineration. The $Ca(OH)_2$ slurry was used as an acid gas (HCl, $SO_2$) treatment materials and the removal efficiency for the products from the neutralization of acid gas in SDA and combustion ash was simulated at the bag filter. The simulation result has been corresponded with the treatment efficiency of emitted gas from the actual industrial waste incinerator and it is presumed to be used to forecast the efficiencies of flue gas treatment system in the future.

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.63-68
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• 2006

Effects of oxidizer inlet velocity on NO emission characteristics of 0.2MW oxy-fuel combustor have been experimentally investigated. The NO formation process in the oxy-fuel combustion is extremely sensitive even for the small fraction of nitrogen in oxidizer. By increasing the oxidizer velocity, flame length is reduced due to the enhanced turbulent mixing. The increased oxidizer velocity also results in the decreased flame temperature through the elevated entrainment rate of the recirculated product and the corresponding NO emission is drastically decreased. Experimental results clearly indicate that the entrained product gases play a crucial role to decrease the temperature at the flame zone and the post flame zone where the thermal NO is mainly formed.

• Journal of Food Hygiene and Safety
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• v.16 no.1
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• pp.61-65
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• 2001

To investigate the optimum condition of 3-monochloro-1, 2-propanediol(MCPD) analysis, gas chromatography with electron capture detector was used. Determination of MCPD derivatized with phenylboric acid was more effective than that of underivatized MCPD. In derivatization of MCPD with phenyl boric acid, there were no significantly different between boiling for 2min at 9$0^{\circ}C$ and vortexing for 5min at room temperature. Extrelut column was suitable for extraction of MCPD diluted in 20% NaCl solution and recovery rates were higher than direct extraction of MCPD with ethyl acetate. But, the method of direct extraction of MCPD with ethyl acetate was useful for rapid ants qualitative analysis. The sample extracted in soysauce(ganjang) was derivatized with phenylboric acid and analyzed by gas chromatography-mass selective detector. That was confirmed as MCPD-phenylboronate.

• Journal of Animal Science and Technology
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• v.66 no.1
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• pp.103-114
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• 2024

This study was done to investigate the effects of the incorporation of Achyranthes japonica extracts (AJE) in diet on the production parameters of growing pigs. Exp 1: Total, 105 crossbred pigs (average body weight: 24.47 ± 2.46 kg) were used in a 6-week feeding trial. Pigs (seven replicates, five pigs per pen) were allotted randomly to three treatments. Dietary treatments: CON (basal diet); basal diet with 0.025% AJE, and basal diet + 0.050% AJE). Growth performance, nutrient digestibility, fecal microbial count, and fecal noxious gas were assessed in this study. Average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F) were not affected by the addition of up to 0.05% AJE. In the case of apparent total tract digestibility (ATTD), dry matter (DM), nitrogen (N), and digestible energy (DE) were not changed in 3rd and 6th weeks of the feeding trial through the addition of AJE up to 0.05% in the growing pig diet. In microbial count, Lactobacillus and Escherichia coli count at 3rd and 6th week was similar in all the treatment diets. The inclusion of AJE at levels up to 0.05% in growing pig diet had no effect on the production of NH3, H2S, acetic acid, and CO₂ in the feces. After ending the Exp 1, a total of nine pigs were divided into three treatment groups. Treatment diets were included, TRT1, basal diet + powder quercetin 30 g; TRT2, basal diet + powder quercetin 150 g; TRT3, basal diet + powder quercetin 300g. Rate of absorption in blood was increased with the higher dose of quercetin. The results suggested incorporation of AJE up to 0.05% has no significant effect on ADG, ADFI, and G:F, as well as DM, N, and DE digestibility, fecal microbial count, and fecal noxious gas emission in growing pigs, even though no negative effect was found.