• Korean Journal of Soil Science and Fertilizer
• /
• v.30 no.1
• /
• pp.29-34
• /
• 1997

This experiment was carried out to investigate the effects of nitrate concentration in culture solution on the growth and the uptake of inorganic elements in Tomato plant in the greenhouse. Tomato plants(cv. TVR-2) were grown with nitrate concentrations 8, 16, 24, 32cmol/l, based on Japan ENSI standard solution. Dry weights of lamina and petiole increased with the nitrate concentration. However, the dry weight of fruit was the highest in the treatment of nitrate concentration of 16cmol/l. The proportion of dry weights of vegitative organ to reproductive organ was the lowest in the treatments of nitrate concentrations of 16cmol/l and it increased with the nitrate concentration. The fruit yield was the highest at the treatment of nitrate concentration of 16cmol/l. With the increase of nitrate level the concentrations of N, $NO_3-N$, Ca and Na increased in lamina and petioles. The concentrations of K, P, S and Cl tended to decline in the nitrate concentration of 16 and 32cmol/l. These results indicate that optimum nitrate concentrations in a tomato grown by hydroponics change with growth stage, and the optimum concentrations for vegitative and reproductive stage were 8 and 16cmol/l, respectively. It also was proved that the nitrate concentrations in the culture solution affected antagonistically the uptake of inorganic anion in tomato : In low nitrate level $Cl^-$ uptake was affected much, while $SO_4{^{2-}}$ and $H_2PO_4{^-}$ uptake were affected in high nitrate level.

• Journal of Korean Society for Atmospheric Environment
• /
• v.32 no.5
• /
• pp.536-546
• /
• 2016

The diurnal variations of $O_3$ and $NO_2$ in an urban park and the effects of air temperature and wind speed on the diurnal variations are investigated. $O_3$ and $NO_2$ concentrations were observed at a site in an urban park of Seoul from 27 July 2015 to 9 August 2015. The $O_3$ and $NO_2$ concentrations observed in the urban park are compared to those observed at the Gangnam air quality monitoring station (AQMS). The $O_3$ concentration is higher in the urban park than at the Gangnam AQMS in the daytime because the amount of $O_3$ dissociated by NO is smaller as well as partly because the amount of $O_3$ produced in the oxidation process of biogenic volatile organic compounds (VOCs) is larger in the urban park than at the Gangnam AQMS. The $NO_2$ concentration is lower in the urban park than at the Gangnam AQMS during day and night because the observation site in the urban park is relatively far from roads where $NO_x$ is freshly emitted from vehicles. The difference in $NO_2$ concentration is larger in the daytime than in the nighttime. To examine the effects of air temperature and wind speed on the diurnal variations of $O_3$ and $NO_2$, the observed $O_3$ and $NO_2$ concentrations are classified into high or low air temperature and high or low wind speed days. The high $O_3$ and $NO_2$ concentrations in the daytime appear for the high air temperature and low wind speed days. This is because the daytime photochemical processes are favorable when the air temperature is high and the wind speed is low. The scatter plots of the daytime maximum $O_3$ and minimum $NO_2$ concentrations versus the daytime averages of air temperature and wind speed show that the daytime maximum $O_3$ and minimum $NO_2$ concentrations tend to increase as the air temperature increases or the wind speed decreases. The daytime maximum $O_3$ concentration is more sensitive to the changes in air temperature and wind speed in the urban park than at the Gangnam AQMS.

• Journal of Environmental Health Sciences
• /
• v.22 no.3
• /
• pp.28-36
• /
• 1996

The objects of this study were to investigate emissions of air pollutant the particles as well as the combustibility of the low grade domestic anthracite coal and imported high-calorific bituminous coal in the fluidized bed coal combustor. The production of air pollution from anthracite-bituminous coal blend combustion in a fluidized bed coal combustor was evaluated. The effects of air velocity and anthracite fraction on the reaching time of steady state condition was also evaluated. We used coal samples the domestic low grade anthracite coal with heating value of 2,010 kcal/kg and the imported high grade bituminous coal with heating value of 6,520 kcal/kg. The experimental results are presented as follows. The time of reaching to steady state was affected by the temperature variation. The steady state time was about 120 minute at 0.3 m/s which was the fastest. It has been found that $O_2$ and $CO_2$ concentration were reached steady state at about 100 minute. As the height of fluidized bed becomes higher, the concentration s of $SO_2$ and $NO_x$ mainly increased. The concentration of freeboard was the highest and emission concentration was diminished. Also, as anthracite fraction increased, the emission of $SO_x$ concentration was increased. But, it has been found that the variation of $NO_x$ concentration with anthracite fraction was negligible and the difference of emission concentration according to air flow rates was negligible, too. It has been found that $O_2$ concentration decreased and $CO_2$ concentration increased as the height of fluidized bed increased. As anthracite fraction increased, the mass of elutriation particles increased, and $CO_2$ concentration decreased. Also, as air velocity increased, $O_2$ concentration decreased and $CO_2$ concentration increased. Regardless-of anthracite fraction and flow rate, the combustible weight percentage in elutriation particles were high in the case of fine particles.

• Journal of Energy Engineering
• /
• v.10 no.4
• /
• pp.379-386
• /
• 2001

This experimental study deals with on Nitric Oxide Formation & Reduction in Industrial Bunner. In this study, Laser-induced fluorescence (LIF) techniques have been used for quantitative measurements of Nitric Oxide. The NO A-X (0, 0) Vibrational band around 226 nm was excited using a XeCl excimer-pumped dye laser. And on-line excitation used $P_{21}+Q_1(14.5)/R_{12}+Q_2(20.5)/P_1(23.5)$ transition, for minimizing the other interferential effect. The measurements were taken NO concentration distribution in double swirling diffusion flame. In this swirl burner, NO concentration in downstream fo the flame decrease as primary/secondary air ratio increases.

• Journal of the korean society of oceanography
• /
• v.32 no.4
• /
• pp.191-201
• /
• 1997

To test the roles of NO$_3^-$ concentration and light as controlling factors of NO$_3^-$ uptake in the NO$_3^-$-low and -high environments and to assess the significance of night-time nitrogen (N) uptake in estimating the daily N uptake rate, 2 diel studies of N uptake were conducted in NO$_3^-$-low (the eastern part of the Yellow Sea) and NO$_3^-$-high (the marginal ice zone of the northwestern Weddell Sea) environments on June 14 to 15, 1996 and January 15 to 16, 1995, respectively. Ourobservations confirmed that NO$_3\;^-$ uptake by phytoplankton is mainly determined by ambient NO$_3^-$ concentration in NO$_3^-$-low environment and by light in NO$_3^-$-high environment, respectively, Our results suggest the need for diel studies to accurately estimate the daily N uptake rates and thus new and regenerated production because the daily rates calculated without considering the night-time N uptake would be significantly underestimated (up to 41%), particularly in the NO$_3^-$-low environment.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.8
• /
• pp.1010-1020
• /
• 2014

Ballast water effluent treated by an electrolytic method contains reactive chlorine species and disinfection by-products (DBPs). In this study, we conducted whole effluent toxicity (WET) testing and ecological risk assessment (ERA) to investigate its ecotoxicological effects on marine environment. WET testing was carried out for three marine pelagic organisms, i.e., diatom Skeletonema costatum, rotifer Brachionus plicatilis and fish Paralichthys olivaceus. The biological toxicity test revealed that S. costatum was the only organism that showed apparent toxicity to the effluent; it showed no observed effect concentration (NOEC), lowest observable effect concentration (LOEC) and effect concentration of 50% (EC50) values of 12.5%, 25.0% and 83.3%, respectively, at brackish water condition. In contrast, it showed insignificant toxicity at seawater condition. B. plicatilis and P. olivaceus also showed no toxicities to the effluent at the both salinity conditions. Meanwhile, chemical analysis revealed that the ballast water effluent contained total residual oxidants (TROs) below $0.03{\mu}g/L$ and a total of 20 DBPs including bromate, volatile halogenated organic compounds (VOCs), halogenated acetonitriles (HANs), halogenated acetic acids (HAAs) and chloropicrin. Based on ERA, the 20 DBPs were not considered to have persistency, bioaccumulation and toxicity (PBT) properties. Except monobromoacetic acid, the ratio of predicted environmental concentration (PEC) to predicted no effect concentration (PNEC) of the other 19 DBPs did not exceed 1. Thus, our results of WET testing and ERA indicated that the ballast water effluent treated by electrolysis and subsequently neutralization was considered to have no adverse impacts on marine environment.

• Journal of Korean Society for Atmospheric Environment
• /
• v.30 no.2
• /
• pp.128-138
• /
• 2014

This study has analyzed the concentration variation of four air pollutants ($PM_{10}$, $NO_2$, CO, and $SO_2$) during the typhoon periods over 10 years (2002~2011). In this study, 10 typhoon events which had rainfalls in Korean Peninsula were selected during the study period. The analysis was performed using the observation data of both the air pollutants and rainfall. In order to examine and compare the concentrations of the air pollutants between normal periods and typhoon periods, we have obtained monthly average concentrations from July to September and daily average concentrations during typhoon periods. For the period from July to September, 34% of the total rainfalls can be explained by typhoons, and the concentration of air pollutants during the typhoon period was lower than the normal period. In addition, the concentration variations of the pollutants during the typhoon period were analyzed according to two categories: differences in the concentrations between the day before and the day of the typhoon (Case 1) and between the day before and after the typhoon (Case 2). The results indicated that the reduction rate of $PM_{10}$, $NO_2$, CO, and $SO_2$ was 30.1%, 17.9%, 11.6%, 9.7% (Case 1) and 22.8%, 21.0%, 9.0%, 8.0% (Case 2), respectively. This result suggested that air quality was significantly improved during the typhoon period than after the typhoon period by the rainfall.

• Korean Journal of Environmental Biology
• /
• v.17 no.2
• /
• pp.153-158
• /
• 1999

Uptakes of N and P by Phragmites japonica Steudel. are determined in continuous flow tanks as a function of hydraulic retention time (HRT, days) and nutrient concentration (NC). Results show that the uptake was higher at shorter HRT and higher nutrient concentration, and the regression equations were estimated. Mean above ground biomass of Phragmites japonica in the middle reaches of Sagimak stream was 335.92 g/$m^2$, and estimated uptake by this vegetation were 7.31~20.15 NH$_4$-N, 31.15~95.84 NO$_3$-N, and 4.09~11.48 PO$_4$-P mg/$m^2$/day in Sagimak stream, respectively when HRT was 1~5 days. According to this study, it is concluded that Phragmites japonica Steudel. are suitable for water quality improvement of stream through nutrient uptake at short HRT and high concentration.

• Animal Bioscience
• /
• v.34 no.2
• /
• pp.192-197
• /
• 2021

Objective: The present study evaluated the preservation of ram semen at 0℃ using soybean lecithin with a Tris-fructose extender. Methods: Semen was collected by artificial vagina ejaculation from six rams with proven fertility. High quality ejaculates were diluted by soybean lecithin (0.25%, 0.5%, 0.75%, 1.0%, 1.25%) using Tris-fructose extender and control (Tris-fructose egg yolk extender), respectively. The ejaculates were diluted to a concentration of 5×108 sperm/mL, followed by cooling to 0℃ in 90 min and maintaining the temperature for 12 days. The diluted semen samples were examined and recorded for sperm progressive motility, acrosome integrity at 0, 24, 72, 144, 216, 288 h, respectively. Two hundred and twenty-three ewes were inseminated for 216 h with optimal soybean lecithin concentrated semen or control via trans-cervical insemination. Results: The results showed that there were no differences in sperm progressive motility at 0, 24, 72, and 144 h (p>0.05). After 216 h, the sperm progressive motility in the control group and 0.5% concentration groups was significantly higher when compared to 0.25% concentration (p<0.05). The 0.5% concentration group demonstrated the highest survival rate and had no difference with the control group (p>0.05). At 216 h, the sperm progressive motility of all groups was still above 50%. The acrosome integrity of all groups was decreased with prolongation of storage time, but there was no difference at each time point (p>0.05). There was no significant difference in the lambing rate and pregnancy rate between the 0.5% concentration group and the control group (p>0.05). Conclusion: These results suggest that ram sperm is capable of fertilization after preservation at 0℃ with 0.5% of soybean lecithin in Tris-based extender substituted for egg yolk and produce normal offspring after insemination.

• Journal of Sericultural and Entomological Science
• /
• v.40 no.1
• /
• pp.70-77
• /
• 1998

This study was carried out in order to find out the relationship between physical and chemical properties of silk fiber treated by concentrated calcium nitrate solution. The tensile, thermal and dynamic mechanical properties are also examined on Ca(NO3)2 treated silk fibers. The tensile properties of silk fibers treated by calcium nitrate changed with a concentration. The thermal behavior were also affected by the concentration of calcium nitrate. The degradation temperature (endotherms) and glass transition temperature shifted to lower temperature as the treated concentration increased. It is thought that the physical properties are strongly related to the structure and morphology of Ca(NO3)2 treated silk fibers. As a result, these give property changes with a concentration dependence.