• Resources Recycling
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• v.29 no.5
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• pp.48-54
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• 2020

Sulphuric acid (H₂SO₄) leaching and hydrolysis were experimented for the recovery of titanum dioxide (TiO₂) from the water-leached residue followed by soda-roasting spent SCR catalysts. Sulphuric acid leaching of Ti was carried out with leachate concentration (4~8 M) and the others were fixed (temp.: 70 ℃, leaching time: 3 hrs, slurry density: 100 g/L, stirring speed: 500 rpm). For recovering of Ti from the leaching solution, hydrolysis precipitation was conducted at 100 ℃ for 2 hours in various mixing ratio (leached solution:distilled water) of 1:9 to 5:5. The maximum leachability was reached to 95.2 % in 6 M H₂SO₄ leachate. on the other hand, the leachability of Si decreased dramatically 91.7 to 3.0 % with an increase of H₂SO₄ concentration. Hydrolysis precipitation of Ti was proceeded with leaching solution of 8 M H₂SO₄ with the lowest content of Si. The yield of precipitation increased proportionally with a dilution ratio of leaching solution. Moreover, it increased generally by adding 0.2 g TiO₂ as a precipitation seed to the diluted leaching solution. Ultimately, 99.8 % of TiO₂ can be recovered with the purity of 99.46 % from the 1:9 diluted solution.

• Land and Housing Review
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• v.14 no.4
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• pp.111-120
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• 2023

Indoor air quality has become increasingly important with the increase in time spent in residential environments, impact of external fine dust, yellow dust, and the post-COVID 19 pandemic. Residential mechanical ventilation plays a key role in addressing indoor air quality. The legal standard for residential air changes per hour in Korea is 0.5 ACH. However, there are no standards for the location of supply and return vents. This study atempts to analyze the impact of ventilation performance based on the location of supply and return vents. An experiment was conducted using the CO₂ tracer gas concentration decay method in a mock-up house set inside a large chamber to minimize external influences. The experimental results indicated that the commonly used combination of 2 supply and 2 return vents in living room spaces had a lower mean age of air than the combination of 1 supply and 2 return vents. Using multiple supply and return vents had lower mean age of air than using just 1 supply and 1 return vent.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.2
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• pp.139-143
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• 2014

This study was conducted to investigate the germination and growth response by Salinities of Spergularia marina Griseb grown in the western coastal region in South Korea. The germination was investigated for 10 days at temperature $10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$ in order to examine the germination of Spergularia marina Griseb by NaCl concentration 0.0, 0.3, 0.5, 1.0, 2.0%. The germination of NaCl concentration 0.0~1.0% was 90% over at $15^{\circ}C$ treatment, but the germination of NaCl concentration 2.0% was 0% at all temperature treatments. To identify the growth response of Spergularia marina Griseb according to the salinity, Spergularia marina Griseb was cultivated for 8 weeks in Hoagland culture medium and sea water. In nutrient solution culture, growth was best in NaCl 50mM among 0~400 mM concentrations and in 0, 12.5, 25, 50, 100% of sea water, growth was best in 12.5% (dilution ratio with fresh water) treatment. Spergularia marina Griseb's inorganic component contents according to salinity showed that $Na^+$ content increased, but contents of $K^+$, $Ca^+$, $Mg^+$ decreased. As a result, appropriate condition for Spergularia marina Griseb's germination is considered to be maintained at $15^{\circ}C$ and in less than NaCl 1.0% of salinity. When nutrient solution culture, NaCl 0.3% of treatment level is considered to be the optimum salinity.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.4
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• pp.362-371
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• 2016

The distribution patterns of Chromophoric Dissolved Organic Matter (CDOM) and the chemical characteristics of CDOM in the Seomjin river estuary were investigated in March, June and July 2012 in order to determine the spatial and temporal variability of CDOM along the salinity gradient considering the effects of mixing, nutrients and Chl a. The average CDOM values were $1.0{\pm}0.3m^{-1}$, $1.3{\pm}0.4m^{-1}$, and $1.4{\pm}0.3m^{-1}$ in March, June and July, respectively. A high concentration of CDOM (greater than $1.5m^{-1}$) was found at the head of the river which decreased towards the river mouth to as low as less than $0.5m^{-1}$. The average concentrations of CDOM increased from the dry season (March and June) to the wet season (July), and the average slope values ($S_{300-500}$), which were used as indicators of CDOM characteristics and sources, were in the range of $0.013-0.018m^{-1}$. The CDOM and $S_{300-50}$ values showed that not only the concentration of CDOM but also the chemical properties of DOM clearly changed between upstream and downstream in the Seomjin river. CDOM and FDOM showed a negative correlation with salinity ($R^2$ > 0.8), and CDOM was positively correlated with FDOM. Furthermore, the mixing pattern of CDOM was confirmed as conservative for all seasons. The main environmental factors influencing the concentration of CDOM was confirmed as conservative for all seasons. The main environmental factors influencing the concentration of CDOM were salinity (mixing) and water temperature, which meant the dilution of low CDOM seawater, was the controlling factor for the spatial distribution of CDOM. Increases in water temperature seemed to induce the production of CDOM during summer (June and July) through the biological degradation of DOM either by microbial activity or photo-degradation.

• The Korean Journal of Physiology
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• v.24 no.1
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• pp.27-37
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• 1990

The extrafetal transfer of $Li^{+}$ in amniotic fluid was studied in 45 pregnant rabbits. LiCl solution was administered either intravenously to mother or directly into the amniotic sac and monitored the appearance and disappearance of $Li^{+}$ in the amniotic fluid, then calculated the transfer rate of $Li^{+}$ of extrafetal origin. To study the transplacental $Li^{+}$ transfer, a solution of 150 mM LiCl was infused continuously via maternal vein (initial dose: 0.7 mmol/kg, maintaining dose: 0.03 mmol/kg/min) and the $Li^{+}$ concentration was measured in maternal blood and amniotic fluid after 60 and 120 minutes of infusion. Change in the volume of aminotic fluid was determined by Congo red dilution method at the same time. Effects of duration of gestation was not considered in this study. Extrafetal transport of $Li^{+}$ into the amniotic fluid was estimated by comparing the $Li^{+}$ concentration and volume of amniotic fluid determined before and after ligating the placental vessels. Extrafetal $Li^{+}$ transport from the amniotic fluid was determined by observing the time dependent disappearance of $Li^{+}$ and Congo red in amniotic fluid after injecting 0.5 ml solution of 15 mM or 90 mM LiCl and 50 mg/ml Congo red. Following are the results obtained: 1) During infusion of LiCl through maternal vein the ratio of the aminotic $Li^{+}$/maternal plasma $Li^{+}$ increased significantly along with the increment of fetal weight. 2) The volume of amniotic fluid of larger fetuses than 20.5 gm increased significantly during administration of LiCl while that of smaller fetuses did not change. 3) After umbilical cord ligation the $Li^{+}$ concentration of amniotic fluid of larger fetuses than 20.5 gm was decreased to $59.9{\pm}10.3%$ and $56.9{\pm}42.9%$ $(mean{\pm}S.D.)$ of those of control group after 60 and 120 minutes of LiCl infusion respectively. In amniotic fluid of smaller fetuses than 20.5 gm, there was no significant difference between control and ligation groups. 4) The disappearance rate of Congo red in the amniotic fluid was $45.2{\pm}8.2%/hr$. 5) The disappearance rate of $Li^{+}$ after intraamniotic injection of LiCl depended on the amount injected. On injecting $7.5\;{\mu}mol$ LiCl, $Li^{+}$ disappeared rapidly from the amniotic fluid and the rates after 60 min and 90 min were $97.0{\pm}2.8,\;98.5{\pm}2.0%$ respectively. On injecting $45\;{\mu}mol$ LiCl, the rates were $56.0{\pm}15.4,\;78.9{\pm}14.5%$ at 60 and 90 min. 6) From the above results it was concluded: a) $Li^{+}$ transfer into the amniotic fluid increased along with the fetal growth and one half of $Li^{+}$ influx is through the extrafetal route even after the maturation of fetal kidney. b) One half of the $Li^{+}$ transfer from the amniotic fluid was through swallowing of fetus, while the remaining half was transfered rapidly through amniotic membrane, which was concentration limited.

• Korean Journal of Environmental Biology
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• v.36 no.3
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• pp.359-369
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• 2018

Harmful algal blooms (HABs) are a serious problem for public health and fisheries industries, thus there exists a need to investigate the possible ways for effective control of HABs. In the present study, we investigated the algicidal effects of a newly developed GreenTD against the HABs (Chattonella marina, Heterosigma akashiwo, Cochlodinium polykriokides, and Heterocapsa circularisquama) and non-HABs (Chaetoceros simplex, Skeletonema sp. and Tetraselmis sp.), which is focused on the different population density and concentration gradients of algicidal substances. The time series viability of target alga was assessed based on the activity of Chl. a photosynthetic efficiency in terms of $F_v/F_m$, and in vivo fluorescence (FSU). Effective control of Raphidophyta, C. marina and H. akashiwo was achieved at a GreenTD concentration of $0.5{\mu}gL^{-1}$ and $0.2{\mu}gL^{-1}$, respectively, and regrowth of both the species was not observed even after 14 days. The inhibitory ratio of the dinoflagellate, C. polykriokides was more than 80% at $0.2{\mu}gL^{-1}$ of GreenTD. H. circularisquama was constantly affected in the presence of $0.2{\mu}gL^{-1}$ of GreenTD in the high- and low-population density experimental groups. On the other hand, diatoms, C. simplex, and Skeletonema sp. were not significantly affected even in the presence of $0.2{\mu}gL^{-1}$ of GreenTD and exhibited re-growth activity with the passage of incubation time. In particular, green alga Tetraselmis sp. remained unaffected even in the presence of the highest concentration of GreenTD ($1.0{\mu}gL^{-1}$), implying that non-HABs were not greatly influenced by the algicidal substances. As a result, the algicidal activity of GreenTD on the harmful and nonharmful algae was as follows: raphidophyte>dinoflagellates>diatoms>green alga. Consequently, our results indicate that inoculation of GreenTD substances into natural blooms at a threshold concentration ($0.2{\mu}gL^{-1}$) can maximize the algicidal activity against HABs species. If we consider the dilution and diffusion rate in the field application, it is hypothesized that GreenTD will demonstrate economic efficiency, thus leading to effective control against the target HABs in the closed bay.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.513-521
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• 2009

The primary goal of this research was to develop an optimized analytical procedure for soil analysis based on ion-selective microelectrodes for agricultural purposes, which can perform on-site measurement of various ions in soil easily and rapidly. For the simple and rapid on-site diagnosis, an analysis of soil chemicals was performed employing a multicomponent-in-situ-extractant and an evaluation of ionselective microelectrodes were conducted through the regressive correlation method with a standard analytical approach widely employed in this area. Examination of sensor responses between various soil nutrient extractants revealed that 0.01M HCl and 1M LiCl provided the most ideal Nernstian response. However, 1M LiCl deteriorated the selective response for analytes due to high concentration (1M) of lithium cation. Thus, employing either 0.1M HCl as an extractant followed by 10 times dilution, or 0.01M HCl as an extractant without further dilution was chosen as the optimal extractant composition. A study of regressive correlation between results from ion-selective microelectrodes and those from the standard analytical procedure showed that analyses of $K^+$, $Na^+$, $Ca^{2+}$, and $NO_3{^-}$ showed the excellent consistency between two methods. However, the response for $NH_4{^+}$ suffered the severe interference from $K^+$. In addition, the selectivity for $Mg^{2+}$ over $Ca^{2+}$ was not sufficient enough since available ionophores developed so far do not provide such a high selectivity for $Mg^{2+}$. Therefore, as an agricultural on-site diagnostic instrument, the device in development requires further research on $NH_4{^+}$ analysis in the soil sample, development of $Mg^{2+}$-selective ionophore, and more detailed study focused on potassium, one of the most important plant nutrients.

• Food Science of Animal Resources
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• v.30 no.1
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• pp.87-94
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• 2010

The aim of the present study was to develop polyclonal antibodies to regional inedible adipocytes of pigs and investigate the effect of these antibodies on adipocytes in vitro. As antigens, abdominal and subcutaneous adipocyte PMPs from pigs were injected into sheep 3 times per 3 wk intervals for passive immunization, and non-immunized serum, antisera against abodominal (AAb) or subcutaneous adipocyte PMPs (SAb) were collected before and after the injections. Titers of the antisera obtained from sheep and their cross-reactivities with the heart, kidney, liver, lung, muscle, and spleen of pig were determined by ELISA. Isolation and culture of abdominal and subcutaneous adipocytes from pigs were performed to analyze LDH concentration. At a 1:1,000 dilution, little antibody reactivity was observed for non-immunized serum whereas both AAb and SAb had relatively strong reactivity up to a dilution of 1:16,000. These findings may indicate that strong antibodies against adipocyte PMPs can be developed using an immunological approach. Extremely low reactivity of AAb and SAb was detected with the PMPs of the organs. Both antisera most strongly reacted with each adipocyte PMPs and showed statistically (p<0.05) higher cross-reactivities compared with the non-immunized serum. In conclusion, these results may indicate that the present polyclonal antibodies against regional inedible adipocyte PMPs are well developed and are safe against cross-reactivities with the organs of pigs. Further studies on the in vivo nutritional safety and fat reduction of these antibodies in pigs will be required fat-reduced high quality pork production.

• Economic and Environmental Geology
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• v.22 no.4
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• pp.303-314
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• 1989

The electrum-silver-sulfide mineralization of the Geojae island area was deposited in three stages (I, II, and carbonate) of quartz and calcite veins that crosscut Late Cretaceous volcanic rocks and granodiorite(83 m.y.). Stages I and II were terminated by the onset of fractunng and breCCIation events. Fluid inclusion data suggest that the gold-sulfide-bearing stages I and II each evolved from an initial high temperature( near $370^{\circ}C$) to a later low temperature(near $200^{\circ}C$). Each of those stages represented a separate mineralizing system which cooled prior to the onset of the next stage. The relationship between homogenization temperature and salinity in stages I and II suggests a complex history of boiling, cooling and dilution. Evidence of boiling indicates a pressure of < 100 bars, corresponding to a depth of 500 to 1,250m assummg hthostatlc and hydrostatic pressure regimes, respectively. Fluid inclusion and mineralogical evidence suggest that the electrum-silver mineralization was deposited at a temperature of $220-260^{\circ}C$ from ore fluids with salinities between 1.9 and 8.1 equivalent wt.% NaCl. Total sulfur concentration is estimated to be $10^{-3}$ to $10^{-4}$ molal. The estimated $fs_2$ and $fo_2$ range from $10^{-11.8}$ to $10^{-14}$ atm and $10^{-35}$ to $10^{-36}$ atm, respectively. The chemical conditions indicate that the dominant sulfur species in the ore forming fluids was a reduced form($H_2S$). Rapid cooling and dilution of ore-forming fluids by mixing with less-evolved meteoric waters led to gold-silver deposition through the breakdown of the bisulfide complex($Au(HS)_2$) as the activity of $H_2S$ decreased.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.105-113
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• 2003

Successful operation of a reactor can be accomplished when it is operated at proper D depending on the state of degradation. Operation at high D leads to the washout of biomass in the reactor while operation at low D leads to product inhibition due to the accumulation of excess VFA. These appear to limit the production of hydrogen to reach a higher level. Operation by D control was performed to improve the efficiency of hydrogen fermentation of food waste. Although simple organic matters were rapidly degraded in the early stage (day 1-2), proper VFA concentration and pH values were kept in the reactor at D of $4.5d^{-1}$, which was previously reported to be optimum initial D. High butyrate/acetate (B/A) ratios over 3.2 were obtained. Without D control, the reduction of simple organic matters after day 2 caused the decrease of VFA production and the increase of pH. Hydrogen production also decreased, as microbial proliferation was less than microbial loss by washout. However, the reactor performance was dramatically improved at D control from 4.5 to $2.3d^{-1}$. It showed the highest B/A ratios over 2.0 among the reactors on day 4-7. The second hydrogen peak appeared on day 4, resulting in the highest fermentation efficiency (70.8%) among the reactors. It was caused by the enhanced degradation of slowly degradable matters. The COD removed was converted to hydrogen (19.3%), VFA (36.5%), and ethanol (15.0%). Therefore, the strategy using D control, depending on the state of degradation, was effective in improving the efficiency of hydrogen fermentation.