• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.532-537
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• 2005

Increasing of body weight has been one of the important economic factors in the poultry industry. Insulin-like growth factor (IGF)-I is a polypeptide that serves to regulate muscle development and body growth. Moreover, IGF-I is related to feed efficiency. However, there are few studies regarding the regulatory roles of chicken IGF-I/-II compared with that of mammals. Especially, the Korean Native Ogol Chicken (KNOC) has a lean body growth and its body weight is generally lighter than the broiler chicken. Therefore, this study was conducted to investigate associations among serum IGF-I/-II concentration, feed efficiency, and body growth in KNOC. The body weight and feed intake of KNOC were recorded from 20 to 36 weeks at 2 weeks intervals, and blood was taken every 2 weeks. Serum IGF-I/-II were measured by RIA. Chickens were divided into two groups, high and low serum IGF-I concentration. Generally, feed efficiency and growth performance (body weight and weight gain) in the high serum IGF-I group were higher than those of the low group during the experimental period. In particular, the body weight of the IGF-I high group were significantly different from those of the IGF-I low group at 34 and 36 weeks, respectively (p<0.05). Moreover, body weight, weight gain, and feed efficiency had a significant correlation with serum IGF-I at several weeks (p<0.05 and p<0.01). These results show that IGF-I plays an important role in body growth and suggests a possibility that serum IGF-I could be used as a selection marker for body growth in KNOC.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.172-181
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• 2005

Collection Efficiency of a tritium bubbler being used at domestic nuclear power plants was studied. Equilibrium is attained while tritium vapour in air passes through the bubbler. When a lot of gas sample passes through the bubbler, the tritium concentration of water is raised and volume of water is decreased or increased. These phenomena give effect to the collection efficiency. Estimation of the tritium concentration of the water agreed with our experiments. If relative humidity is higher than 0.5, the efficiency becomes lower than 1 and if relative humidity is lower than 0.5, the efficiency becomes higher than 1, provided collected tritium is evaluated with original volume of the water. Though the relative humidity is riot 0.5, the efficiency can be maintained near 1 by making $\frac{saturated\; water\; vapour(cm^3_w)\times volume \; of \; gas \; sample(cm^3)}{volume\; of\; water(cm^3)}$ small

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.613-618
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• 2014

In this study, nitrogen doped graphene oxide (GO) was prepared using liquid phase ammonia treatment to improve its electrical properties. Also, the aminated GO was manufactured into a film format and the electromagnetic interference (EMI) shielding efficiency was measured to evaluate its electrical properties. The XPS result showed that the increase of liquid phase ammonia treatment concentration led to the increased nitrogen functional group on the GO surface. The measurement of EMI shielding efficiency reveals that EMI shielding efficiency of the liquid phase ammonia treated GO was better than that of non-treated GO. When GO was treated using the ammonia solution of 21% concentration, the EMI shielding efficiency increased by -5 dB at higher than 2950 MHz. These results were maybe due to the fact that nitrogen functional groups on GO help to improve the absorbance of electromagnetic waves via facile electron transfer.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.69-75
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• 2020

This study was conducted to improve the solid-liquid separation efficiency of clarifiers. To do so, the study did a bio-flocculation experiment simply by controlling the stirring speed (rpm) and baffle angle of a clarifier on a lab scale, but without using a coagulant. For the purpose of the experiment, the feed wall of a clarifier was so improved that a baffle could be installed on the clarifier. Then, it was ensured to change its stirring speed (to 0.0rpm, 0.6rpm, and 1.2rpm), with the angle fixed at 10°. As a result, it was found that concentration efficiency increased by 2.0%, and effluent removal efficiency (SS concentration) by 7.8%, at a stirring speed of 0.6ppm. This indicates the bio-coagulation efficiency of sludge increased with changing stirring speeds. Then, the baffle angle of the sedimentation unit was changed to analyze how the changed baffle angle would affect the sedimentation of sludge. As a result, it was found that the compression of sludge interface was very effective at a baffle angle of 20°. It is hoped that these experimental findings will be useful in improving the sedimentation efficiency of circular clarifiers.

• Journal of Environmental Science International
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• v.32 no.10
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• pp.731-739
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• 2023

In this study, lab-scale phosphorus coagulation/precipitation experiments were performed using three types of polyaluminum chloride (PAC) with different Al contents (10%, 12%, and 17%). The PO₄-P removal efficiencies at various operating conditions, such as initial PO₄-P concentration, initial pH, and Al/P molar ratio, were evaluated, and correlations among the operating factors affecting phosphorus coagulation/precipitation with PAC were derived to optimize the process efficiency. When the initial PO₄-P concentration was 0.065 and 0.161 mmol P/L under an initial pH of 8-10, the optimal PAC dose was 0.126-0.378 and 0.189-0.667 mmol Al/L, respectively. Under these conditions, the Al/P molar ratio was 2.16-6.18 and 1.28-4.30, respectively, and the PO₄-P removal efficiency was in the range of 40.2-92.5%. When the Al/P molar ratio was 2 or less under an initial pH condition of 6-8, the PO₄-P removal efficiency was approximately ≤40% owing to insufficient Al³⁺ ions. However, when the Al/P molar ratio is 3-5, the PO₄-P removal efficiency improved to approximately 80-90%. Thus, the optimal Al/P molar ratio to achieve a PO₄-P removal efficiency of over 90% was determined to be approximately 4 in the PO₄-P coagulation/precipitation process using PAC.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.1
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• pp.48-54
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• 2019

This research was carried out to investigate the plant growth, inorganic ion and amino acid content characteristics in a halophyte, Suaeda glauca, under different NaCl concentrations for cultivating in the reclaimed land. S. glauca was hydroponically cultivated under 0, 50, 100, 200, 300 and 400 mM NaCl concentrations with Hogland's nutrient solution. To evaluate growth response under different NaCl concentrations, plant height and number of branches, dry weight, Fv/Fm value, and photosynthetic efficiency were investigated. To find out physiological characteristic, inorganic ion contents and amino acids in the plant were evaluated. The optimum concentration of NaCl for plant growth were 50 mM. The plant growth were gradually decreased in the concentration ranged from 100 to 400 mM. As increasing of NaCl concentration, Na ion was increased, but K, Ca, Mg ions were decreased in the plant. The amino acid contents were varied due to NaCl concentrations, but most of amino acids content in total plant was the lowest at 50 mM. Conversely, proline was exceptionally high at 50 mM of NaCl concentration. The Fv/Fm value was the highest at 50 mM of NaCl concentration. From these results, the optimum salt concentration for the growth of S. glauca was 50 mM, but the plant seems to adapt in a variety of salt environments in view of the change of ions and amino acids depending on salt concentration and the maintenance of photosynthetic efficiency even under high salt condition.

• Journal of Forest and Environmental Science
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• v.23 no.1
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• pp.29-33
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• 2007

This study was purposed to elucidate the best optimum sites by ecophysiological response measurements of Kalopanax pictus samplings of plantation. The diurnal changes of the stomatal transpiration, water use efficiency, water potential, and intercellullar $CO_2$ concentration of leaves were measured by the portable IR $CO_2$ analyzer. The results obtained are summarized as follows. 1) The daily stomatal transpiration rate was highest at 10:00 a.m. After 16:00, the stomatal transpiration rate rapidly decreased. 2) The daily water use efficiency was maximum at 8:00 a.m., and then rapidly decreased until midday with decreasing water potential. 3) The daily $C_i/C_a$ ratio rapidly decreased until 9:00 a.m., and then showed a stable value until 16:00, and then rapidly increased. The daily intercellullar $CO_2$ concentration ($C_i/C_a$ ratio) showed the same tendency as water potential changes. Consequently, stomatal transpiration and water use efficiency was increased with high water potential of leaves at am, and then remarkably decreased with low water potential at pm.

• Journal of Environmental Health Sciences
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• v.25 no.3
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• pp.64-69
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• 1999

This study was carried out the removal of Cr(VI) which was known to the toxic pollutant in industry using the process of UV and TiO$_2$ photocatalyst in a circular type reactor. In this experiment, the series of photocatalytic process for the removal of Cr(VI) has been selected as a model reaction in a circular type reactor in order to obtain the basic data on the influence of various experimental parameters such as circulation flow rate, pH of solution, initial Cr(VI) light illumination and TiO$_2$ dosage, and salicylic acid concentration. The results of this study were as follows; 1. With both UV light illumination and TiO$_2$ present, Cr(VI) was more effectively eliminated than with either UV or TiO$_2$ alone. 2. As the circulation flow rate of solution increased, the removal efficiency of Cr(VI) was increased. However, over 2.4 l/min of circulation flow rate, the efficiency wa limited. 3. A increase in the photocatalytic removal of Cr(VI) was noticed with decreasing pH. 4. An increase in the photocatalytic removal of Cr(VI) was noticed with decreasing Initial Cr(VI) concentration and first order kinetics was observed from the result at different initial concentration of Cr(VI). 5. Photocatalytic removal efficiency of Cr(VI) increased with increasing TiO$_2$ dosage. However, over 1.0 g/l of TiO$_2$ dosage, the efficiency reached a plateau. 6. As low concentration of saliculic acid were added, there was an increase in the removal efficiency of Cr(VI). However, over 300 mg/l of salicylic acid, the efficiecy was decreased. It eas found that application of photocatalysis to water treatment that contains both Cr(VI) and salicylic acid was possible.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.675-680
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• 2010

This study was investigated to complement nitrogen removal of low concentration influent municipal sewage. The following are the results of the effect of Internal Recircularion and Step Feed rates on Treatment efficiency at a BOD low concentration influent municipal sewage. Up to 90.0% of BOD, 87.8% of COD, 71.0% of T-N, 75.3% of T-P were removed on average at a low concentration influent. Whereas BOD and T-P were removed without any relations to Step Feed rates, T-N was influenced. Nitrogen removal efficiencies in 80% of Step Feed rates was 65%, which was caused by the lack of Carbon Source for denitrification. Nitrogen removal efficiency in 40% of Step Feed rates was 58%, which means it was not removed but dischared. Consequently, the efficiency was 73%, 80%, and 78% in 70%, 60% and 50% of Step Feed rates, which was concluded as the best range of Step Feed rates. Nitrogen removal efficiency increased under the condition of Internal Recircularion. At over 150% of Internal Recircularion rate, the efficiencies were not affected any more. It is believed that lots of Recircularion caused inflow of DO to anoxic tank. Therefore, the most appropriate Internal Recircularion rate can be concluded as 50~150%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.262-269
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• 2016

This study examined the influent of a sulfur denitrification reactor using nitrified effluent from a batch type reactor. The denitrification efficiency was compared according to the injection type. The nitrogen removal effects were compared with the changes in the EBCT and nitrogen concentration of the influent to determine the optimal operation conditions with the selected injection type. A denitrification efficiency evaluation of a reactor according to the change in injection type and up-flow was performed using a lower organic concentration of the effluent than the down-flow because of the re-precipitation of desorbed microbes and spilled solids. In the up-flow type, organics were controlled by the low concentration than the down-flow type because of solid re-precipitation. The T-N removal efficiency of the up-flow type was 73.3~90.2%, which was more that 10% higher that down-flow type. This means that the up-flow type has a great advantage in removing T-N and organics. The T-N removal efficiency by EBCT at 1hr was 47.3%, and was 88.1% and 90.5% by EBCT 3hr and 5hr, respectively. Therefore, the optimal operation conditions to remove nitrogen was considered to be EBCT for 3hr. After careful consideration of rule of law and T-N removal effects, the T-N load factor in the reactor should remain below $0.443kgT-N/m^3{\cdot}day$ to maintain the legal total nitrogen concentration for discharge, which is 20mg/L.