• Journal of Climate Change Research
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• v.4 no.2
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• pp.115-126
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• 2013

Recently Korea considers the source of biomass burning emissions reflecting national characteristic, so that includes the inventory of emission source but preceding research is rarely implemented in Korea. Therefore, a study on characteristics of greenhouse gas emissions from biomass burning is necessary and it also makes the source management effectively when the climate-atmospheric management system takes effect. In this study, using the manufactured charcoal kiln and the number of experiment was three times to get a reliable experiment result. The sampling time was decided by changing degree in charcoal kiln and charcoal manufacturing process. The results of calculation greenhouse gas emission factor from charcoal kiln were $668g\;CO_2/kg$, $20g\;CH_4/kg$, $0.01g\;N_2O/kg$. Using the emission factor developed in this study, estimate the emissions from charcoal kiln in Korea. The results of calculation were $46,040ton\;CO_2/yr$, $1,378ton\;CH_4/yr$, $0.69ton\;N_2O/yr$ and greenhouse gas emissions applying GWP are as follows. $CH_4$ emissions was $28,947ton\;CO_2eq./yr$, $N_2O$ emissions was $214ton\;CO_2eq./yr$. As a results, Gross emissions of charcoal kiln in Korea was $75,201ton\;CO_2eq./yr$, but the oak used in this study is included to the biomass so emissions of $CO_2$ are excluded. Therefore the net emissions of charcoal kiln in Korea was $29,161ton\;CO_2eq./yr$.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.6
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• pp.85-96
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• 2018

Developed nations have implemented various policies to reduce greenhouse gases since the 1997 Kyoto Protocol in order to minimize the effects of global warming. Korea should also reduce energy consumption in the industrial sector, and the transportation and building sectors in order to achieve its greenhouse gas reduction target of 37 percent compared to the Business As Usual levels. The government implements various laws and regulations for reducing energy consumption. To reduce energy consumption in the building sector, in particular, the Energy Conservation Design Standards are enforced according to the 'Enforcement Support for Green Building Construction'. The amount of electricity used to maintain room temperature at $28^{\circ}C$ in these buildings have a 30% reduction (measured on the walls and rooftop) in power usage compared to buildings not required to meet these standards. Although the effect of these energy savings on landscaping is proven, this demonstration is not effective for energy saving since it is not a suitable method for the 'Energy Saving Design Standards of Buildings'. For landscaping to be effective as far as a component of energy reduction, the perfusion rate of the building should be calculated based on the thermal conductivity of the component materials for the energy saving designs with respect to the basis of Article 14 of the Green Building Act. Therefore, the purpose of this study is to ensure that the planting-based mats currently being widely used in the landscape industry can have insulating performance suitable for the 'Energy Saving Design Standards' of Buildings according to the 'Enable Green Building Construction Methods'.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.95-103
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• 2019

Temperature and relative humidity are important factors in crop cultivation and should be properly controlled for improving crop yield and quality. In order to control the environment accurately, we need to predict how the environment will change in the future. The objective of this study was to predict air temperature and relative humidity at a future time by using a multilayer perceptron (MLP). The data required to train MLP was collected every 10 min from Oct. 1, 2016 to Feb. 28, 2018 in an eight-span greenhouse ($1,032m^2$) cultivating mango (Mangifera indica cv. Irwin). The inputs for the MLP were greenhouse inside and outside environment data, and set-up and operating values of environment control devices. By using these data, the MLP was trained to predict the air temperature and relative humidity at a future time of 10 to 120 min. Considering typical four seasons in Korea, three-day data of the each season were compared as test data. The MLP was optimized with four hidden layers and 128 nodes for air temperature ($R^2=0.988$) and with four hidden layers and 64 nodes for relative humidity ($R^2=0.990$). Due to the characteristics of MLP, the accuracy decreased as the prediction time became longer. However, air temperature and relative humidity were properly predicted regardless of the environmental changes varied from season to season. For specific data such as spray irrigation, however, the numbers of trained data were too small, resulting in poor predictive accuracy. In this study, air temperature and relative humidity were appropriately predicted through optimization of MLP, but were limited to the experimental greenhouse. Therefore, it is necessary to collect more data from greenhouses at various places and modify the structure of neural network for generalization.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.258-267
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• 2020

The agrivoltaic can produce electricity and grow crops on fields at the same time. It is necessary to analyze the cultivation environment and evaluate the crop productivity under agrivoltaic because the shading point changes according to structure of agrivoltaic and sun's position. Two types of "fixing" and "tracing" agrivoltaic were installed, and a rice cultivation experiment was conducted in the fields under each agrivoltaic and without shading (control). "Hyunpoombyeo" was transplanted on June 7, 2019, and grown with fertilization of 9.0-4.5-5.7 kg/10a (N-P-K). Fifteen weather stations were installed under each agrivoltaic to measure solar radiation and temperature, and yield and yield-related elements were investigated by points. The accumulated solar radiation during the rice growing season in fixing was no much difference between points, and that in tracing was much difference between points. However, the average solar radiations of two agrivoltaics were similar. The mean temperature, yield, and yield-related elements showed a significant difference for the shading rate, and decreased with increasing the shading rate except ripening grain rate and 1000 grain weight of fixing agrivoltaic. In the relationship between shading rate and yield, fixing and tracing were fitted to a logistic equation and a simple linear equation, respectively, and showed a high correlation (tracing: R2 = 0.62, fixing: R2 = 0.73). The shading rate variation by point for two types was large despite similar yield variation. Thus, it needs to be more closely examined the relationship of the shading rate for a specific period rather than the shading rate during the whole growing season.

• Journal of Bio-Environment Control
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• v.30 no.1
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• pp.1-9
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• 2021

This study was conducted to examine the changes of photosynthesis, growth, chlorophyll contents and functional material contents in light intensity and EC concentration of wild baby leaf vegetable, Indian lettuce (Lactuca indica L. cv. 'Sunhyang') in DFT hydroponics. The cultivation environment was 25±1℃ of temperature and 60±5% of relative humidity in growth system. At 14 days after sowing, combination effect of light intensity (Photosynthetic Photon Flux Density (PPFD 100, 250, 500 µmol·m-2·s-1) and EC level (EC 0.8, 1.4, 2.0 dS·m-1) of nutrient solution was determined at the baby leaf stage. The photosynthesis rate, stomatal conductance, transpiration rate and water use efficiency of Indian lettuce increased as the light intensity increased. The photosynthesis rate and water use efficiency were highest in PPFD 500-EC 1.4 and PPFD 500-EC 2.0 treatment. The chlorophyll content decreased as the light intensity increased, but chlorophyll a/b ratio increased. Leaf water content and specific leaf area decreased as light intensity increased and a negative correlation (p < 0.001) was recognized. Plant height was the longest in PPFD 100-EC 0.8 and leaf number, fresh weight and dry weight were the highest in PPFD 500-EC 2.0. Anthocyanin and total phenolic compounds were the highest in PPFD 500-EC 1.4 and 2.0 treatment, and antioxidant scavenging ability (DPPH) was high in PPFD 250 and 500 treatments. Considering the growth and functional material contents, the proper light intensity and EC level for hydroponic cultivation of Indian lettuce is PPFD 500-EC 2.0, and PPFD 100 and 250, which are low light conditions, EC 0.8 is suitable for growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.392-402
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• 2021

The present study investigated the effects of tillage practices (deep cultivation [DC] and conventional tillage [CT]) and extended planting dates (mid-June to July) for maize-onion rotation in paddy fields. The silage corn (Zea mays L.) cultivar 'Kwangpyeongok' and the waxy corn cultivar 'Ilmichal' were planted on June 14, July 3, and July 15 in 2019. In both maize, the plant height of June 14 planted was up to 100 cm greater than that of July 15 planted on August 16 and up to 40 cm on August 30. At 30 Days after planting, the leaf area index (LAI) of silage corn planted on July 3 and 15 greater than that of corn planted on June 14 due to high temperature in the early season; however, there were no differences in the LAI of waxy corn according to the planting date. Despite favorable temperature, plants sown on July 3 and 15 experienced high moisture stress during the seedling stage due to consistent rainfall, and waxy corn was highly sensitive to high moisture stress. The total yield of silage corn was 1,232 (845 in TDN), 860 (598 in TDN), and 765 (508 in TDN) DW kg·10a^-1 for plants sown on June 14, July 3, and July 15, respectively. The fresh marketable ear yield of waxy corn was 872, 814, and 525 FW kg·10a^-1 for plants sown on June 14, July 3, and July 15, respectively. After the completion of maize cultivation, onion seedlings (Allium cepa L.) were transplanted on November 12, 2019, and harvested on May 27, 2020. Neither summer tillage nor maize planting date affected onion growth or yield. The marketable onion yield was 8,305 and 7,848 kg·10a^-1 with DC and CT, respectively. In conclusion, DC did not improve maize growth or yield under paddy conditions. Mid-June to early July is a practical window for maize planting for growers in this region.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.376-383
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• 2022

The current study, which consisted of two independent studies (laboratory and greenhouse), was carried out to project the hypothesis fungi-spray scheduling for leaf mold and gray leaf spot in tomato, as well as to evaluate the effect of temperature and leaf wet duration on the effectiveness of different fungicides against these diseases. In the first experiment, tomato leaves were infected with 1 × 10⁴ conidia·mL^-1 and put in a dew chamber for 0 to 18 hours at 10 to 25℃ (Fulvia fulva) and 10 to 30℃ (Stemphylium lycopersici). In farm study, tomato plants were treated for 240 hours with diluted (1,000 times) 30% trimidazole, 50% polyoxin B, and 40% iminoctadine tris (Belkut) for protection of leaf mold, and 10% etridiazole + 55% thiophanate-methyl (Gajiran), and 15% tribasic copper sulfate (Sebinna) for protection of gray leaf spot. In laboratory test, leaf condensation on the leaves of tomato plants were emerged after 9 hrs. of incubation. In conclusion, the incidence degree of leaf mold and gray leaf spot disease on tomato plants shows that it is very closely related to formation of leaf condensation, therefore the incidence of leaf mold was greater at 20 and 15℃, while 25 and 20℃ enhanced the incidence of gray leaf spot. The incidence of leaf mold and gray leaf spot developed 20 days after inoculation, and the latency period was estimated to be 14-15 days. Trihumin fungicide had the maximum effectiveness up to 168 hours of fungicides at 12 hours of wet duration in leaf mold, whereas Gajiran fungicide had the highest control (93%) against gray leaf spot up to 144 hours. All the chemicals showed an around 30-50% decrease in effectiveness after 240 hours of treatment. The model predictions in present study could be help in timely, effective and ecofriendly management of leaf mold disease in tomato.

• Journal of the Korean Chemical Society
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• v.65 no.3
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• pp.197-202
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• 2021

In this study, activated clay treated with H₂SO₄ (20% by weight) and heat at 90 ℃ for 8 h for acid white soil was used as an adsorbent for the removal of PO₄^3--P in water. Prior to the adsorption experiment, the characteristics of activated clay was examined by X-ray Fluorescence Spectrometry (XRF) and BET surface area analyser. The adsorption of PO₄^3--P on activated clay was steeply increased within 0.25 h and reached equilibrium at 4 h. At 5 mg/L of low PO₄^3--P concentration, roughly 98% of adsorption efficiency was accomplished by activated clay. The adsorption data of PO₄^3--P were introduced to the adsorption isotherm and kinetic models. It was seen that both Freundlich and Langmuir isotherms were applied well to describe the adsorption behavior of PO₄^3--P on activated clay. For adsorption PO₄^3--P on activated clay, the Freundlich and Langmuir isotherm coefficients, K_F and Q, were found to be 8.3 and 20.0 mg/g, respectively. The pseudo-second-order kinetics model was more suitable for adsorption of PO₄^3--P in water/activated clay system owing to the higher correlation coefficient R² and the more proximity value of the experimental value q_e,exp and the calculated value q_e,cal than the pseudo-first-order kinetics model. The results of study indicate that activated clay could be used as an efficient adsorbent for the removal of PO₄³-P from water.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.255-264
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• 2022

This study was performed to investigate the effects of dietary supplementation with ginseng by-products on growth, organ development, blood biochemical profiles, immune response, and stress parameter of broilers reared in high ambient temperatures. One hundred one-day-old male chicks (Ross 308) were used. At week two, the birds were randomly allocated into five dietary groups; control (CON), 0.5% ginseng berry (GB1), 1.0% ginseng berry (GB2), 0.5% ginseng leaves and stems (GLS1), and 1.0% ginseng leaves and stems (GLS2). The temperature was maintained at 32±1℃from 9 AM to 5 PM. Growth, serum immunoglobulins and corticosterone levels were monitored and analyzed. No significant differences among groups were observed in growth. However, during the finisher period (21~35d) and overall period (7~35 d), body weight gain in all supplemented groups tended higher than CON group. Blood biochemical profiles did not significantly differ among treatment groups except in bilirubin level. Serum immunoglobulins and corticosterone level showed no significant differences among groups. IgM and IgG levels were numerically higher in GLS1 than in other groups, but the difference was not significant. Corticosterone level also tended lower in all supplemented groups than in CON group, and larger decreases were observed in groups with higher ginseng by-product concentration. In conclusion, dietary supplementation of ginseng by-products shows potential to reduce heat stress in growing broilers with no negative effect on productivity.

• Resources Recycling
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• v.31 no.1
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• pp.65-77
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• 2022

A study was conducted in Korea on the leaching behavior and possibility of recovery of vanadium and other valuable metals from domestic vanadium titanomagnetite (VTM) by direct acid leaching. In this study, a VTM concentrate containing 0.8% V₂O₅ was used, and the ratio of magnetite to ilmenite was calculated as 1.9:1 by using the HSC program. The leaching behavior of vanadium from the VTM was similar to that of iron, and it was affected by the concentration of sulfuric acid and temperature. Further, titanium could be leached in the form of TiOSO₄ at a temperature higher than 75℃. To improve the leaching efficiency of V, Fe, and Ti in VTM, reductive sulfuric acid and oxidative sulfuric acid leaching were performed. When Na₂SO₃ was used as a reducing agent, the leaching rate of vanadium was 80% of that in that case of leaching by sulfuric acid. Similarly, the leaching rate of titanium increased from 20% to 50%. When Na₂S₂O₈ was used as an oxidation agent, most of the vanadium was leached, and the main residue found by XRD analysis was ilmenite. In studies on the possibility of recovering valuable metals, the selective extraction of metals is hardly achieved by solvent extraction from oxidation leaching solutions; however, in this study, Cyanex 923, a solvation extractant from reductive leaching solutions, could selectively extract Ti.