• Journal of Mushroom
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• v.10 no.1
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• pp.3-8
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• 2012

In this study, to produce Flammulina velutipes mushroom liquid spawn efficiently and effectively the effects of explosive aeration (supplying air with tiny bubbles) of the liquid culture medium on carbon dioxide concentration and residual sugar content in the medium on carbon dioxide concentration and residual sugar contentin the medium were measured. Carbon dioxide concentrations were measured at the outlet of the incubator. On the third day the explosive aeration greatly increased mycelial growth of the liquid spawn, and carbon dioxide concentration also greatly increased but decreased after 5 days. Free sugar contents in the liquid culture consistantly decreased up to 7 days and thereafter was not detected. The weight of the mycelia were maintained similar levels after 3 days. Total nitrogen content in the liquid medium constantly decreased during the 11days of explosive aeration. The content of free sugars in 7 days of culture was the lowest level, thus the inoculum incubated for 6~7 days was thought to be the most effective. Carbon dioxide concentration measurement at the outlet of the container during the liquid spawn incubation required low cost but was efficient to estimate the degree of mycelial growth to be used as a simple indicator.

• Asian Journal of Turfgrass Science
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• v.20 no.1
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• pp.83-91
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• 2006

This research was initiated to enhance the tilth of fine-textured soil for turf growth by incorporation of crumb rubber shredded from used tires. A specific objective was to determine the physical properties of soil mixes amended with different grade and amount of crumb rubber in soils. Two soils and three different grades(3.5, 6.5 and 9.5 mm) of crumb rubber were used. The soils selected were an Arenzville silt loam(coarse-silty, mixed, nonacid, mesic Typic Udifluvents) and a Hosmer silty clay loam(fine-silty, mixed, mesic Typic Fragiudalfs). The amount of crumb rubber mixed in soil ranged from 0 to 0.4 $g{\cdot}g^{-1}$(using 0.05 $g{\cdot}g^{-1}$) increments and 0 as a control. For each treatment, soil cores were constructed following the recommendation by the United States Golf Association Green Section Record. Results indicated that porosity of the mixes decreased as the amount of crumb rubber increased. Regardless of the grade of crumb rubber, mixes with less than 0.15 $g{\cdot}g^{-1}$ of crumb rubber in fine-textured soil could not enhance their macro-porosity and hydraulic conductivity. However, as the amendment increased over 0.15 $g{\cdot}g^{-1}$, the tilth of the mixes had improved significantly macro-porosity, hydraulic conductivity and air permeability, as compared with a control.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.318-318
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• 2011

자연수를 가압(4~5기압)하면서 물과 공기의 비를 4:1~3:1로 혼합하면 수체 내 초미세기포(Diameter $3{\sim}10{\mu}m$)가 발생하는데 이를 산소용해수라 하며 수질정화시설 또는 양식장 등에 널리 사용되고 있다. 산소용해수의 특징은 기포의 비표면적이 넓고 10시간 이상 포화 농도를 유지하여 수체에 잔류하는 시간이 길기 때문에, 일반 산기석을 활용한 포기나 순산소 용해 등의 타 방법과 구별된다. 산소용해수의 산소전달효율은 기존 방법과 큰 차이를 보이기 때문에 실제 적용시에는 대상수를 이용하여 산소전달계수($K_{L}a$)를 사전에 산정할 필요가 있다. 본 연구에서는 한국건설기술 연구원의 안동 수자원 환경실험센터 내 실외형 콘크리트 사각반응수조에 산소용해장치 및 확산장치를 결합한 일체형 시스템을 적용시켜 2010년 9월~2011년 1월의 5개월간 결과를 분석, 본 장치의 $K_{L}a$를 산정 후 수질정화의 활용 면에서 검토하였다. $K_{L}a$의 산정에는 다양한 방법이 이용되나 용존 산소 농도의 제어에 한계가 있는 실외 대형실험장에 적합한 Lewis and Whitman의 Two-film 이론에 근거한 정상포기법을 적용하였다. 체적 $80m^3$의 수조 내에서 현장 유지용수를 대상으로 실험한 결과 산소전달계수는 $0.324\pm0.050$/min, 포화농도는 8.64 mg $O_2$/L, 도달시간은 11 /min이 산정되었으며, 이는 기존 산기석 포기의 산소전달계수 범위인 $0.105\pm0.019$ /min보다 약 3.1배 높은 결과를 보였다. 또한, 확산장치의 수류 순환 방향 및 정도를 검토하기 위하여 실험수조에서 1m단위로 격자를 구성한 후 초음파 유속계로 실측한 결과 0.0~2.5 m/s 의 평면적 유속범위를 도출하였다. 그리고 전체 순환을 고려했을 때 용존산소는 약 8시간 후 8.64 mg $O_2$/L 값에 도달하여 안정화 되었으며, 강한 수류순환과 산소용해수에 의해 하상에 존재하는 퇴적물들의 이송 및 산화촉진을 유도하였다. 이를 근거로 실험수조의 체적과 기준 가동시간인 8시간을 적용시켰을 때, 실험구 수질은 대조구와 비교하여 COD, T-N, T-P가 모두 25~35% 개선되었다. 이 결과는 여과공정 없이 단순 순환만을 고려한 물리적 수질정화 방법의 단독 활용 가능성을 나타내며, 기존 연구에서 나타난 SOD (Sediment oxygen demand) 저감 능력을 감안할 때 향후 폐쇄성 수역의 수질관리에도 효율적으로 활용할 수 있음을 시사한다.

• Korean journal of food and cookery science
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• v.24 no.4
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• pp.536-541
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• 2008

In order to determine the effects of strawberry powder on the baking quality of cakes, yellow layer cakes were prepared with four freeze-dried strawberry powders substitutes, at levels of 0%, 1%, 2%, 3%, 4% and 5%. Then, the physical properties, baking properties and sensory characteristics of the finished cakes were assessed. The cakes were stored for 6 days at $22^{\circ}C$ and the change in hardness during storage was evaluated. The Viscosity of the doughs, as well as the specific gravity, increased as the amount of strawberry powder in the flour increased. The volume indices of the strawberry powder cakes were less than that of control, but the other indices did not differ from those of the controls. The crust color of the strawberry cakes evidenced a reduction in L. a and b values. The crumb color also evidenced a reduction in the L and b values, but the a values increased. Sensory characteristics were evaluated by 60 students from the Dept. of Food and Biotechnology. Crust color, crumb color, moistness, softness, taste and overall acceptance were measured via a 5-scale acceptance test. The crust color of cakes containing more than 3% strawberry powders and the crumb color of all strawberry cakes evidenced lower scores than the controls. Cakes containing 5% strawberry powders were least acceptable in terms of overall characteristics. Although cakes prepared with flour containing up to 4% strawberry powder were less acceptable than the controls, general sensory scores ranged in an average${\sim}$like range. The incorporation of strawberry power into cakes was shown to increase the overall hardness.

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.243-246
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• 1993

For extending the shelf-life of Yukwa (oil puffed rice cake) which is one of the most favorable Korean traditional rice snack, the Yukwa was packed in $O_2$ preventive container and substituted the air with $N_2$ gas or packed with $O_2$ absorbent (ageless sachet). The quality of Yukwa stored at $35^{\circ}C$ was evaluated by POV, AV and TBA including sensory evaluation. The POV of oil in Yukwa of $N_2$ substitute pack and absorbent sachet included were 5.3 and 11.9 meq/kg, respectively, while no packing (control) was 195.5 meq/kg after 90 days storage at $35^{\circ}C$. AV and TBA were also same trend but the gap with the control was not so big. The Yukwa, $N_2$ gas substituted, was better in quality than absorbent treatment in sensory evaluation and no difference was detected in quality of 90 days storage Yukwa at $35^{\circ}C$ with 15 days. The main reason for lower sensory score of absorbent treatment was that the $O_2$ absorbent also absorbed the flavor component of Yukwa.

• Korean Journal of Environment and Ecology
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• v.35 no.6
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• pp.659-668
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• 2021

The purpose of this study is to propose a ventilation corridor management plan to improve the thermal environment for Busan Metropolitan City. To this end, the characteristics of hot and cool spots in Busan were identified by conducting spatial statistical analysis, and thermal image data from Landsat-7 satellites and major ventilation corridors were analyzed through WRF meteorological simulation. The results showed the areas requiring thermal environment improvement among hot spot areas were Busanjin-gu, Dongnae-gu, industrial areas in Yeonje-gu and Sasang-gu, and Busan Port piers in large-scale facilities. The main ventilation corridor was identified as Geumjeongsan Mountain-Baekyangsan Mountain-Gudeoksan Mountain Valley. Based on the results, the ventilation corridor management strategy is suggested as follows. Industrial facilities and the Busan Port area are factors that increase the air temperature and worsen the thermal environment of the surrounding area. Therefore, urban and architectural plans are required to reduce the facility's temperature and consider the ventilation corridor. Areas requiring ventilation corridor management were Mandeok-dong and Sajik-dong, and they should be managed to prevent further damage to the forests. Since large-scale, high-rise apartment complexes in areas adjacent to forests interfere with the flow of cold and fresh air generated by forests, the construction of high-rise apartment complexes near Geumjeongsan Mountain with the new redevelopment of Type 3 general residential area should be avoided. It is expected that the results of this study can be used as basic data for urban planning and environmental planning in response to climate change in Busan Metropolitan City.

• Korean Journal of Plant Resources
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• v.35 no.2
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• pp.362-371
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• 2022

This study was conducted to analyze the fragrance characteristics of Cymbidium 'Saelbit' and 'Midan' according to floral organs. As test materials, full bloom flowers were divided into four organs: sepal, petal, labellum, and column. Using the gas chromatography (GC) based electronic nose, fragrance patterns, intensity, and volatile components were analyzed. Principle component analysis (PCA) and discriminant factorial analysis (DFA) plots by electronic nose data showed that volatiles of both cultivars have a distinct difference in fragrance patterns according to the floral organs, and the value of fragrance distance and pattern discrimination index (PDI) between samples was significantly high between control and sepals in both cultivars. Among the main fragrance components, several components including nootkatone were detected in both cultivars and all floral organs. However, few components such as decane were found in specific cultivar or floral organs. These results will provide useful information to select suitable materials with desired fragrance and to enhance the utilization of domestic Cymbidium cultivars. In addition, considering the recent negative perception of artificial ingredients and the growing demand for natural materials, continuous researches on scent properties of promising cultivars are required.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.665-672
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• 2023

Purpose: Underground utility tunnel is facility that is jointly house infrastructure such as electricity, water and gas in city, causing condensation problems due to lack of airflow. This paper aims to prevent electricity leakage fires caused by condensation by detecting whether the control panel door in the underground utility tunnel is open using a deep learning model. Method: YOLO, a deep learning object recognition model, is trained to recognize the opening and closing of the control panel door using video data taken by a robot patrolling the underground utility tunnel. To improve the recognition rate, image augmentation is used. Result: Among the image enhancement techniques, we compared the performance of the YOLO model trained using mosaic with that of the YOLO model without mosaic, and found that the mosaic technique performed better. The mAP for all classes were 0.994, which is high evaluation result. Conclusion: It was able to detect the control panel even when there were lights off or other objects in the underground cavity. This allows you to effectively manage the underground utility tunnel and prevent disasters.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.4
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• pp.285-303
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• 2023

Interest in building underground spaces is increasing for the creation of downtown infrastructure and efficient space utilization. A representative method of utilizing underground space is a tunnel, and in addition to road tunnels, the construction of utility tunnels such as power conduits and utility conduits is gradually increasing. The current basic tunnel construction method can be divided into NATM (New Austrian Tunnelling Method) and TBM (Tunnel Boring Machine). The NATM is a reliable method, but it is accompanied by vibration and noise due to blasting. In the case of the TBM excavation method, there are disadvantages in terms of construction period and construction cost, but it is possible to improve economic feasibility by introducing appropriate complementary methods. In this study, a blasting method was develop using the NATM after TBM pre-excavation using the protective shield method. This is a method that compensates for the disadvantages of each tunnel construction method, and is expected to reduce construction costs, blasting vibration, and noise. In order to review the performance of the developed method, an experiment was conducted to evaluate the performance of explosion-proof tube to which a protective shield scale model was applied, and the impact of blasting vibration of the protective shield method was analyzed.

• Geotechnical Engineering
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• v.10 no.4
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• pp.39-52
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• 1994

The group effect of inclined ground anchor should be considered in design, but it has been hardly studied due to the difficulties of experimental or theoretical study. In this study, the model tests for the inclined ground anchors are made, and the displacements and strain fields of ground around anchor surface are analysed. As the results of this study, the group effect of the inclined ground anchor in air dried sand ground does not show even though two anchor surfaces are very close(10.7cm, surface to surface). That is to say, ,in the case that the final failure surface by pullout of anchor shows on the anchor surface, the pullout resistances of single anchors are almost same as those of the group anchors in these model tests.