• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.719-727
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• 2021

In the field of architecture, retractable devices capable of responding flexibly to the environment have been applied widely to large structures. Among these devices, the aesthetically pleasing retractable membrane is lightweight so that the membrane can be opened easily using only a traction device. On the other hand, because the towed membrane moves as it is connected to the main cable by a trolley, the number of trolleys needed increases in proportion to the roof's area. This study proposes an optimal model for an open-type trolley (OTT), which is used widely in these devices, using topology optimization. The analysis used the ANSYS program. A new model was proposed based on the results and reviewed through the feedback. Through this process, it was possible to develop a prototype with increased durability and reduced weight. For OTT, optimization was performed based on static analysis and the boundary conditions, so three prototypes were designed. A comparison of the proposed trolley with the conventional one under the same conditions revealed an up to 71.04% decrease in volume while the yield-strength reached 8.67 to 11.43%. In conclusion, the optimal trolley proposed was found to be reliable in terms of economy and stability.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.1
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• pp.47-60
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• 2021

Hydrogen is a next-generation energy source, and according to the roadmap for activating the hydrogen economy, it is expected that industries to stably produce, store, and transport of hydrogen as well as the supply of hydrogen fuel cell vehicles will be made rapidly. Accordingly, safety measures for accidents of hydrogen vehicles in confined spaces such as tunnels are required. In this study, as part of a study to ensure the safety of hydrogen fuel cell vehicles in road tunnels, a basic investigation and research on the risk of fire and explosion due to gas leakage and hydrogen tank rupture among various hazards caused by hydrogen fuel cell vehicle accidents in tunnels was conducted. The following results were obtained. In the event of hydrogen fuel cell vehicle accidents, the gas release rate depends on the orifice diameter of TPRD, and when the gas is ignited, the maximum heat release rate reaches 3.22~51.36 MW (orifice diameter: 1~4 mm) depending on the orifice diameter but the duration times are short. Therefore, it was analyzed that there was little increase in risk due to fire. As the overpressure of the gas explosion was calculated by the equivalent TNT method, in the case of yield of VCE of 0.2 is applied, the safety threshold distance is analyzed to be about 35 m, and number of the equivalent fatalities are conservatively predicted to reach tens of people.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.1
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• pp.68-81
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• 2021

The agricultural ecosystem is one of the major sources of greenhouse gas (GHG) emissions. In order to search for climate change adaptation options which mitigate GHG emissions while maintaining crop yield, it is advantageous to integrate multiple models at a high spatial resolution. The objective of this study was to develop a tool to support integrated assessment of climate change impact b y coupling the DSSAT model and the DNDC model. DNDC Regional Input File Tool(DRIFT) was developed to prepare input data for the regional mode of DNDC model using input data and output data of the DSSAT model. In a case study, GHG emissions under the climate change conditions were simulated using the input data prepared b y the DRIFT. The time to prepare the input data was increased b y increasing the number of grid points. Most of the process took a relatively short time, while it took most of the time to convert the daily flood depth data of the DSSAT model to the flood period of the DNDC model. Still, processing a large amount of data would require a long time, which could be reduced by parallelizing some calculation processes. Expanding the DRIFT to other models would help reduce the time required to prepare input data for the models.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1143-1157
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• 2020

In this study, a criteria for the SWAT model calibration method in SWAT-CUP which considers multi-site and multi-variable observations was presented. For its application, the SWAT model was simulated using long-term observed flow, soil moisture, and evapotranspiration data in Yongdam study watershed, investigating the hydrological runoff characteristics and water balance in the water cycle analysis. The model was calibrated with different parameter values for each sub-watershed in order to reflect the characteristics of multiple observations through one-by-one calibration, appropriate settings of model simulation run/iteration number (1,000 simulation runs in the first iteration and then 500 simulation runs for the following iterations), and executions of partial and all run in SWAT-CUP. The flow simulation results of watershed outlet point, ENS 0.85, R2 0.87, and PBIAS -7.6%, were compared with the analysis results (ENS 0.52, R2 0.54, and PBIAS -22.4%) applied in the other batch (i.e., non one-by-one) calibration approach and showed better performances of proposed method. From the simulation results of a total of 15 years, it was found that the total runoff (streamflow) and evapotranspiration rates from precipitation are 53 and 39%, and the ratio of surface runoff and baseflow (i.e., sum of lateral and return flow, and recharge deep aquifer) are 35 and 65%, respectively, in Yongdam watershed. In addition, the analytical amount of available water (i.e., water yield), including the total annual streamflow (daily average 21.8 m3/sec) is 6.96 billion m3 per year (about 540 to 900 mm for sub-watersheds).

• Korean Journal of Clinical Laboratory Science
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• v.53 no.1
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• pp.88-95
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• 2021

Aucklandia lappa Decne., a traditional herbal medicine, has been used to treat various diseases, including asthma, coughs, rheumatism, and diarrhea. In the present study, the effects of the oral administration of Aucklandia lappa Decne. extract on hair growth was investigated in hair-removed mice. A 70% ethanol extract of Aucklandia lappa Decne. (ALD) was prepared, and the extraction yield and total polyphenol content of ALD were measured as 27.30±0.01 and 28.39 mg gallic acid equivalent (GAE)/g, respectively. The oral administration of ALD to hair-removed CL57BL/6 mice for six weeks had no significant effects on food intake and body weight changes. Biochemical and histological examinations also showed that the oral administration of ALD for six weeks had no significant effect on the liver and kidney functions. On the other hand, hair growth was significantly higher in the ALD group than the control group and the Pancidil group (positive control). In addition, the number of hair follicles and the degree of collagen production in the dermis were significantly higher in the ALD group than in the control and pancidil groups. These results suggest that ALD is a potential source of nutricosmetics with hair growth-promoting effects.

• Journal of People, Plants, and Environment
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• v.23 no.6
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• pp.655-665
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• 2020

Background and objective: This study was conducted to compare the cultivation environment, growth of cut flowers, and management performance of conventional farms and smart farms growing the standard cut chrysanthemum, 'Jinba'. Methods: Conventional and smart farms were selected, and facility information, cultivation environment, cut flower growth, and management performance were investigated. Results: The conventional and smart farms were located in Muan, Jeollanam-do, and conventional farming involved cultivating with soil culture in a plastic greenhouse, while the smart farm was cultivating with hydroponics in a plastic greenhouse. The conventional farm did not have sensors for environmental measurement such as light intensity and temperature and pH and EC sensors for fertigation, and all systems, including roof window, side window, thermal screen, and shading curtain, were operated manually. On the other hand, the smart farm was equipped with sensors for measuring the environment and nutrient solution, and was automatically controlled. The day and night mean temperatures, relative humidity, and solar radiation in the facilities of the conventional and the smart farm were managed similarly. But in the floral differentiation stage, the floral differentiation was delayed, as the night temperature of conventional farm was managed as low as 17.7℃ which was lower than smart farm. Accordingly, the harvest of cut flowers by the conventional farm was delayed to 35 days later than that of the smart farm. Also, soil moisture and EC of the conventional farm were unnecessarily kept higher than those of the smart farm in the early growth stage, and then were maintained relatively low during the period after floral differentiation, when a lot of water and nutrients were required. Therefore, growth of cut flower, cut flower length, number of leaves, flower diameter, and weight were poorer in the conventional farm than in the smart farm. In terms of management performance, yield and sales price were 10% and 38% higher for the smart farm than for the conventional farm, respectively. Also, the net income was 2,298 thousand won more for the smart farm than for the conventional farm. Conclusion: It was suggested that the improved growth of cut flowers and high management performance of the smart farm were due to precise environment management for growth by the automatic control and sensor.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.199-202
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• 2000

The leaf color varies with the contents of pigments, especially chlorophylls and carotenoids. Teichung 65 (T.65), a japonica rice, with pgl(pale-green leaf) gene exhibits pale green color on the whole plant from seedling to harvest. This study conducted to evaluate the agronomic characters and examine the chloroplasts of 'pgl' plants in parents and BC$_1$F$_2$ of T.65(pgl) xSuweon ${345}^2$. The average grain yield of pale-green-leaf individuals in F$_2$ was the same as T.65(pgl) but that of green-leaf individuals was much higher than that of Suweon 345. The contents of chlorophyll a(Ca), chlorophyll b(Cb) and total chlorophyll content(Ct) of T.65(pgl) in flag leaf were lower than those of Suweon 345, but the Ca/Cb ratio of T.65(pgl) was higher than that of Suweon 345 during from 15 days after heading (DAH) to 60 DAH. The SPAD value of T.65(pgl) in flag leaf was lower than that of Suweon 345, but that in the second and the third leaves was similar to that of Suweon 345. The SPAD value of pale-green-leaf individual group was lower than that of green individual group in upper three leaves. The structural difference of chloroplasts in flag leaf between T.65(pgl) and Suweon 345 through TEM at 20 DAH was not detected, but the number of osmium granules in chloroplast of T.65(pgl) were higher than that of Suweon 345.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.4
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• pp.237-242
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• 2022

'Jogreen' (Secale cereal L.) was developed for rye cultivars not fast heading but winter hardiness with high yields, which was open-pollinated by ten rye cultivars including 'Chochun' in 1995. Its average heading date was April 15, which was five days earlier on average compared with 'Gogu'. At harvest, the plant height of 'Jogreen' was 117 cm which was taller than 'Gogu' as much as 6 cm. The number of stems was 983 per m², which was higher than that of Gogu (979). 'Jogreen' did not show both winter kill and powdery mildew, but showed lodging as 3 which is similar to 'Gogu'. The biomass in the dry weight base was 8.1 MT ha^-1, and showing was 4% higher than 'Gogu'. The crude protein content of 'Jogreen' was 11.9%, 0.8% lower than that of 'Gogu', and the acid detergent fiber (ADF) and the neutral detergent fiber (NDF) contents were 36.9% and 64.5%, respectively, higher than that of 'Gogu'. The total digestible nutrients (TDN) content also was low, but the TDN content was 5.09 ton ha^-1, which was higher than that of 'Gogu'. The seed productivity of 'Jogreen' was approximately 3.1 ton ha^-1, which was similar to the check. 'Jogreen' was found to be resistant to winter kill and can be adapted to after-paddy-rice cultivation in all Korean provinces. 'Jogreen' is likely to lodge, therefore, farmers should follow the recommended seeding rate and fertilization rate.

• Journal of Mushroom
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• v.21 no.3
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• pp.179-184
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• 2023

The development of automated bottle cultivation systems has facilitated the large-scale production of Pleurotus ostreatus, a commonly cultivated oyster mushroom species in South Korea. However, as the consumption of this product is decreasing and production quantities are exceeding demand, farmers are seeking various other mushroom types and cultivars. In response to this, we have developed a new oyster mushroom cultivar named 'Sena'. This high-yielding cultivar has a white pileus and excellent quality. The white oyster mushroom cultivars 'Goni' and 'Miso' were selected as parental strains from the genetic resources of the National Institute of Horticultural and Herbal Science's Mushroom Division. By crossing their monokaryons, hybrids were developed and subjected to cultivation trials and characteristic evaluations to select the superior cultivar. The optimal temperature for 'Sena' mycelial growth is 25-30℃, with inhibition occurring at temperatures above 30℃, whereas the temperature for mushroom growth is 14-18℃. The mushrooms grow in clusters, with the white pileus having a shallow funnel shape. Optimal mycelial growth occurs in malt extract agar medium. When cultivated in 1,100 cc bottles, the 'Sena' cultivar had 35 available individuals, surpassing the number 16 available from the control cultivar 'Goni'. The yield per bottle also increased by approximately 157 g, a 24% increase over the control cultivar amount. When 300 g samples of harvested mushrooms were packed and stored at 4℃ in a cold storage facility for 28 days, the weight loss rate of 'Sena' was approximately 4.22%, lower than that of 'Goni'. Moreover, the changes in pileus and stipe whiteness (measuring 6.99 and 8.33, respectively) were also lower than those of the control cultivar. Since the appearance of a white cap is crucial for quality assessment, the 'Sena' cultivar is superior to the 'Goni' cultivar in terms of both weight and quality after undergoing low-temperature storage.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.175-188
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• 2023

Global interest in hydrogen energy is increasing as an eco-friendly future energy that can replace fossil fuels. Accordingly, a next-generation hydrogen production technology using microorganisms, nuclear power, etc. is being developed, while a lot of time and effort are still required to overcome the cost of hydrogen production based on fossil fuels. As a way to minimize greenhouse gas emissions in the hydrocarbon-based hydrogen production process, methane direct decomposition technology has recently attracted attention. In order to improve the economic feasibility of the process, the simultaneous production of value-added carbon materials with hydrogen can be one of the most essential aspects. For that purpose, various studies on catalysis related to the quality and yield of high-value carbon materials such as carbon nanotubes (CNTs). In terms of process technology, a number of the research and development of fluidized-bed reactors capable of continuous production and improved gas-solid contact efficiency has been attempted. Recently, methane direct decomposition technology using a fluidized bed has been developed to the extent that it can produce 270 kg/day of hydrogen and 1000 kg/day of carbon. Plus, with the development of catalyst regeneration, separation and recirculation technologies, the process efficiency can be further improved. This review paper investigates the recent development of catalysts and fluidized bed reactor for methane direct pyrolysis to identify the key challenges and opportunities.