• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.127-137
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• 2021

Air emission charge for nitrogen oxide as a precursor of fine dust has been introduced and implemented within the country from 2020. Therefore, the development of economical combustion technology for NOx reduction has got more needed urgently. This study investigated the air-staging effect as a way to reduce the NOx during combustion of domestic unused forest biomass, recently possible to secure REC (Renewable Energy Certification) as a substitute for overseas wood pellets in a 0.1 MWth circulating fluidized bed combustion test-rig. Operating conditions were comparison with and without air-staging, the supply position of tertiary air (6.4 m, 8.1 m, 9.4 m in the combustor) and variation of air-staging ratio (Primary air:Secondary air:Tertiary air=91%:9%:0%, 82%:9%:9%, 73%:9%:18%). NO and CO concentrations in flue gas, profiles of temperature and pressure at the height of the combustion, unburned carbon in sampled fly ash and combustion efficiency on operating conditions were evaluated. As notable results, NO concentration with air-staging application under tertiary air supply at 9.4 m in the combustor reduced 100.7 ppm compared to 148.8 ppm without air-staging while, CO concentration increased from 52.2 ppm without air-staging to 99.8 ppm with air-staging. However, among air-staging runs, when tertiary air supply amount at 6.4 m in the combustor increased by air-staging ratio (Primary air:Secondary air:Tertiary air=73%:9%:18%), NO and CO concentrations decreased the lowest 90.8 ppm and 66.1 ppm, respectively. Furthermore, combustion efficiency at this condition was improved to 99.3%, higher than that (98.3%) of run without air-staging.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.485-496
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• 2022

Modern agriculture is being transformed into smart agriculture to maximize production efficiency along with changes in the 4th industrial revolution. However, rural areas in Korea are facing challenges of aging, low fertility, and population outflow, making it difficult to transition to smart agriculture. Among ICT technologies, simulation allows users to observe or experience the results of their choices through imitation or reproduction of reality. The combination of the three-dimension (3D) model and the greenhouse simulator enable a 3D experience by virtual greenhouse for fruits and vegetable cultivation. At the same time, it is possible to visualize the greenhouse under various cultivation or climate conditions. The objective of this study is to apply the greenhouse climate management model for simulation development that can visually see the state of the greenhouse environment under various micrometeorological properties. The numerical solution with the mathematical model provided a dynamic change in the greenhouse environment for a particular greenhouse design. Light intensity, crop transpiration, heating load, ventilation rate, the optimal amount of CO₂ enrichment, and daily light integral were calculated with the simulation. The results of this study are being built so that users can be linked through a web page, and software will be designed to reflect the characteristics of cladding materials and greenhouses, cultivation types, and the condition of environmental control facilities for customized environmental control. In addition, environmental information obtained from external meteorological data, as well as recommended standards and set points for each growth stage based on experiments and research, will be provided as optimal environmental factors. This simulation can help growers, students, and researchers to understand the ICT technologies and the changes in the greenhouse microclimate according to the growing conditions.

• Korean Journal of Plant Resources
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• v.36 no.1
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• pp.1-14
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• 2023

This study measured the antioxidant activity and phytochemical content of 192 Boehmeria nivea var. tenacissima (Gaudich.) Miq. collected from six regions in order to identify the possibility of its industrial application. Two antioxidant activity assay (DPPH radical scavenging activity and ABTS radical scavenging activity) and two phytochemical content assay (total polyphenol content (TPC) and total flavonoid content (TFC)) of 192 samples were analyzed. The results showed that the DPPH radical scavenging activity of 192 samples was ranged from 0.02 to 1.35 mgAAE/g, and among them, the samples collected from Goheung (0.53 ± 0.37) and Ulleungdo (0.52 ± 0.28) showed the highest activity. The ABTS radical scavenging activity was showed the ranged from 0.07 to 1.81 mgAAE/g, and the samples collected at Ulleungdo (0.47 ± 0.36) showed the highest activity. The total polyphenol content of 192 samples was 18.6 to 234.8 ugGAE/g, and the samples collected at Mokpo (93.4 ± 34.7) and Jindo (90.4 ± 24.5) showed the highest content. The total flavonoid content was 0.10 to 1.22 mgQE/g and the samples collected at Ulleungdo (0.49 ± 0.31) showed the highest content. In the correlation analysis, there was no significant relationship between the environmental conditions and the antioxidant activity. The total polyphenol content showed a positive correlation with daily temperature difference, and negative correlation with average wind speed and average humidity, and total flavonoid content showed negative correlations with the average temperature, maximum temperature, and minimum temperature. This result can be used as a basic data establish the cultivation conditions of B. nivea var. tenacissima (Gaudich.) Miq. as a functional raw material to increase the usefulness of B. nivea var. tenacissima (Gaudich.) Miq..

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.87-94
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• 2023

Fresh bakery products are widely consumed worldwide and therefore particular requirements for their quality characteristics have been established. The shelf life of bakery products is mainly subjected to microbial spoilage and staling. This study investigated the optimum conditions of modified atmosphere packaging (MAP) application to extend the shelf life of the bakery products. The gas conditions of the headspace in 'Baumkuchen' cake were 0, 30, 70, and 100% CO₂ concentrations and stored at 30℃ for 5 days. The bakery samples were evaluated weight loss, hardness, color change, pH and total aerobic bacteria, yeast and molds count throughout the storage period. Values of the weight loss and hardness were increased over the storage period, meanwhile pH was significantly decreased. However, no significant color changes were observed during storage. It was also found no significant difference between the different gas treatments. Total aerobic bacteria count of the stored samples after day 5 was increased by 6.94 log CFU/g in the air filled package, compared to 6.20 log CFU/g in the 100% CO₂ filled package and 6.02 log CFU/g in the 70% CO₂ filled package. Yeast and molds count were 3.65 log CFU/g in air filled package, 2.66 log CFU/g in 100% CO₂ filled package, 2.64 log CFU/g in 70% CO₂ filled package, 2.86 log CFU/g in 30% CO₂ filled package and 3.31 log CFU/g in 100% N₂ filled package on day 2. In conclusion, it was shown that 70% and 100% CO₂ treatments in the package were effective to reduce microbial growth.

• Journal of the Daesoon Academy of Sciences
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• v.41
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• pp.133-178
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• 2022

This study investigates if four propitious sites (四明堂, sa myeongdang) identified in Daesoon Jinrihoe's The Canonical Scripture correspond with the orthodox descriptions of dragon, energy hub, sand, and water (龍穴砂水, yong hyeol sa su) which are held by Fengshui as conditions necessary for that specific designation. In this study, these conditions, based on the shape of the site-formations, were observed via through on-site surveys and the application of the theories presented by traditional books on Fengshui. First, the dragon veins (龍脈, yongmaek) of the energy hub of the Five Immortals Playing Baduk (五仙圍碁穴 oseonwigi- hyeol) on Mount Hoemun in Sunchang consists of solid soil, is like a spiderweb, rises and lays prone, winds in every direction, and looks almost disconnected while actually remaining connected. Second, the Fengshui characteristics of the energy hub of Worship Held by Buddhist Monks from Abroad (胡僧禮佛穴, hoseungyebul- hyeol) on Mount Seungdal in Muan is that the branching feet (枝脚 jigak) support the mountain range by forming a valley to the left and right of the dragon veins that stretch from the peak of Mount Seungdal. Also, the direction-changing helm (橈棹 yodo) supports the mountain range solidly can be said to be well-developed. It is likewise noted that there is an excellent change in dragon veins in that exhibit curvature that spans being high, low, rising, and lying. This makes it appear as though the dragon is wriggling back and forth. Third, the state of the energy hub of Celestial Maidens Weaving Silk (仙女織錦穴, seonnyojikgeum-hyeol) on Sonryong Ridge in Jangseong County demonstrates overall harmony between mountain and water as it is near Mount Ju and Mount An and has a solid water outlet to which it is tightly fastened such that its energy does not leak out. Meanwhile, the positioning of its blue dragon of the east, red phoenix of the south, white tiger of the west, and black tortoise of the north is so intimate that its long flow can be said to be spinning. The Songryong Ridge area where energy hub was formed between soil and bedrock is the right land for a great favored location as it corresponds with Fengshui logic in an exemplary manner. Fourth, the Fengshui characteristics of the energy hub of Subjects Receiving the Imperial Command (群臣奉詔穴, gunshinbongjo-hyeol) at Baerye-jeon Field in Taein can be described as embracing the village snuggly as it centers around Mount Wangja, and its blue dragon and white tiger respond to each other. Additionally, a clear distinction between host and guest is noticeable in the positions of Mount Ju and Mount An. The flowing body of water in front of the village wraps around that village as a Horizontal Water Formation (橫水局, hoengsuguk), and vigorous vapor from the earth draws breath as the yin-yang energy of the landscape courses through the earth. As dragon veins, the range of the mountain, are like the blood vessels within the human body and the dragon is compared to the limbs, the energy hub of Subjects Receiving the Imperial Command at Baerye-jeon Field in Taein can be identified as a favored location that was formed directly by the sky and earth.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.491-501
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• 2022

Bentonite has been proposed as a buffer and backfill material for high-level radioactive waste repository. Under such repository environment conditions, bentonite is subjected to combined thermal, hydrological, mechanical, and chemical processes. This study evaluates the feasibility of applying X-ray CT technology on the characterization of bentonite under hydration conditions using a newly developed testing cell. The cylindrical cell is made of platic material, with a removable cap to place the sample, enabling to apply vertical pressure on the sample and to measure swelling pressure. The hydration test was carried out with a sample made of Gyeonju bentonite, with a dry density of 1.4 g/cm³, and a water content of 20%. The sample had a diameter of 27.5 mm and a height of 34 mm. During the test, water was injected at a constant pressure of 0.207 MPa, and lasted for 7 days. After one day of hydration, bentonite swelled and filled out the space inside the cell. Moreover, CT histograms showed how the hydration process induced an initial increase and later progressive decrease on the density of the sample. Detailed profiles of the mean CT value, CT standard deviation, and CT gradient provided more details on the hydration process of the sample and showed how the bottom and top regions exhibited a decrease on density while the middle region showed an increase, especially during the first two days of hydration. Later, the differences in CT values with respect to the initial state decreased, and were small at the end of testing. The formation and later reduction of cracks was also characterized through CT scanning.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2B
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• pp.121-135
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• 2010

This study is to assess the effect of potential future climate change on the inflow of agricultural reservoir and its impact to downstream streamflow by reservoir operation for paddy irrigation water supply using the SLURP. Before the future analysis, the SLURP model was calibrated using the 6 years daily streamflow records (1998-200398 and validated using 3 years streamflow data (2004-200698 for a 366.5 $km^2$ watershed including two agricultural reservoirs (Geumgwang8 and Gosam98located in Anseongcheon watershed. The calibration and validation results showed that the model was able to simulate the daily streamflow well considering the reservoir operation for paddy irrigation and flood discharge, with a coefficient of determination and Nash-Sutcliffe efficiency ranging from s 7 to s 9 and 0.5 to s 8 respectively. Then, the future potential climate change impact was assessed using the future wthe fu data was downscaled by nge impFactor method throuih bias-correction, the future land uses wtre predicted by modified CA-Markov technique, and the future ve potentiacovfu information was predicted and considered by the linear regression bpowten mecthly NDVI from NOAA AVHRR ima ps and mecthly mean temperature. The future (2020s, 2050s and 2e 0s) reservoir inflow, the temporal changes of reservoir storaimpand its impact to downstream streamflow watershed wtre analyzed for the A2 and B2 climate change scenarios based on a base year (2005). At an annual temporal scale, the reservoir inflow and storaimpchange oue, anagricultural reservoir wtre projected to big decrease innautumnnunder all possiblmpcombinations of conditions. The future streamflow, soossmoosture and grounwater recharge decreased slightly, whtre as the evapotransporation was projected to increase largely for all possiblmpcombinations of the conditions. At last, this study was analysed contribution of weather, vegetation and land use change to assess which factor biggest impact on agricultural reservoir and stream watershed. As a result, weather change biggest impact on agricultural reservoir inflow, storage, streamflow, evapotranspiration, soil moisture and groundwater recharge.

• Journal of Korean Society of Disaster and Security
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• v.16 no.2
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• pp.15-32
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• 2023

There are some difficulties such as safety problem and need of manpower in measuring discharge by submerging the instruments because of many floating debris and very fast flow in the river during the flood season. As an alternative, microwave water surface current meters have been increasingly used these days, which are easy to measure the discharge in the field without contacting the water surface directly. But it is also hard to apply the method in the sudden and rapidly changing field conditions. Therefore, the estimation of the discharge using the surface velocity in flood conditions requires a theoretical and economical approach. In this study, the measurements from microwave water surface current meter and rating curve were collected and then analyzed by the discharge estimation method using the surface velocity. Generally, the measured and converted discharge are analyzed to be similar in all methods at a hydraulic radius of 3 m or over or a mean velocity of 2 ㎧ or more. Besides, the study computed the discharge by the index velocity method and the velocity profile method with the maximum surface velocity in the section where the maximum velocity occurs at the high water level range of the rating curve among the target locations. As a result, the mean relative error with the converted discharge was within 10%. That is, in flood season, the discharge estimation method using one maximum surface velocity measurement, index velocity method, and velocity profile method can be applied to develop high-level extrapolation, therefore, it is judged that the reliability for the range of extrapolation estimation could be improved. Therefore, the discharge estimation method using the surface velocity is expected to become a fast and efficient discharge measurement method during the flood season.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.311-328
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• 2017

This study was carried out to investigate the changes in soil microorganisms and soil enzymes by split irrigation and organic matter application under no-tillage green house conditions. Soil bacteria and fungi abundances were higher in soybean cake fertilizer than in the soil without the soybean cake fertilizer under whole quantity irrigation. Bacteria and fungi abundances in soil increased with increasing organic fertilizer application rate. Bacteria and fungi amount in the soil increased at half division irrigation in no-treatment of soybean cake fertilizer compared with whole quantity irrigation. Actinomycete amount in the soil decreased with increasing soybean cake fertilizer with whole quantity irrigation while clearly increased in no-treatment of soybean cake fertilizer. Actinomycete amount in soil clearly increased with increasing organic fertilizer input at half division irrigation. Chitinase activity in the soil decreased in soybean cake fertilizer with increasing organic fertilizer input, while increased in no-treatment of soybean cake fertilizer. Chitinase activity in the soil increased at half division irrigation compared with whole quantity irrigation regardless of soybean cake fertilizer input. ${\beta}$-Glucosidase activity in the soil was higher in soybean cake fertilizer than in no-treatment of soybean cake fertilizer with whole quantity irrigation. ${\beta}$-Glucosidase activity in the soil increased with increasing organic fertilizer input, but decreased in above the standard level 66%. ${\beta}$-Glucosidase activity in the soil clearly increased in no-treatment of soybean cake fertilizer at half division irrigation compared with whole quantity irrigation. N-acetyl-${\beta}$-D-glucosaminidase activity was higher in soybean cake fertilizer than in no-treatment of soybean cake fertilizer with whole quantity irrigation. N-acetyl-${\beta}$-D-glucosaminidase activity in the soil increased with increasing organic fertilizer input, but decreased in above the standard level 66%. N-acetyl-${\beta}$-D-glucosaminidase activity in the soil was not significantly different at half division irrigation and whole quantity irrigation in organic fertilizer input, while increased at half division irrigation in no-treatment of soybean cake fertilizer. Acid phosphatase activity increased at standard level 66% in soybean cake fertilizer, while was not significantly different in no-treatment of soybean cake fertilizer. Spore density of Arbuscular Mycorrhizal Fungi (AMF) in the soil increased with increasing organic fertilizer input at whole quantity irrigation in no-treatment of soybean cake fertilizer, while decreased above the standard level 66% in organic fertilizer input. However, spore density of AMF in the soil was not significantly different in soybean cake fertilizer regardless of input amount of organic fertilizer. Root colonization rate of AMF in red pepper roots was not significant difference at two irrigations regardless of soybean cake input.

• Journal of Animal Environmental Science
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• v.12 no.3
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• pp.141-150
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• 2006

To optimise the efficient use of nutrients in pig slurry is to cultivate friendly environmental crops. This field survey is to investigate the actual conditions of pig slurry utilization for cultivation of crops in the agricultural farm, based on the survey for 407 selected farms in 9 provinces included 78 counties in Korea. The results obtained in this survey were summarized as follow ; The motive which came to use pig slurry in the agricultural farm were production of friendly environmental crops (29.7%), economy of chemical fertilizer (25.1%), spontaneously (19.2%), inducement of neighboring farmhouse (16.0%), increase of soil fertility (9.3%), and the others (0.7%), respectively. The proportions of pig slurry application land were 56.5% for.ice paddy, 22.6% for dry field, 13.3% for orchard, 4.4% for controlled agriculture and 3.2% for other, respectively. The number of times of pig slurry utilization per year were once (48.9%), twice (31.9%), thrice (14.0%), and the others (5.2%), respectively. The controversial points of pig slurry utilization were malodor (54.1%), insufficiency of spread equipment (22.1%), inconvenience (14.5%), over application (3.4%), over cost (2.9%), heavy metal (1.7%), sanitation (1.0%) and the other (0.2%), respectively. The results indicated that pig slurry could be used as fertilizer source of friendly environmental crops, but further studies are needed to determine the application method and value of the pig slurry for crop cultivation.