• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.71-71
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• 2018

Sea pollution accidents have been occurred due to the increase of marine ship traffic. Oil spill from the hull hole induced by tanker collision results in the huge sea pollution. Proper and prompt reaction on such oil spill disaster is needed to minimize the damage. Thru-hull emergency wood plug is typically used to manually close small holes, while it is required to develop some mechanical devices for closing large holes in the hull due to huge fluid pressure. Accurate estimation of oil discharge and velocity from such holes are important to develop proper device to control hull hole damage. High resolution CFD modeling investigation on the configurations of hull hole of 7.5 m initial depth and 30 cm diameter, which was observed in the oil spill accident of the Hebei Sprit off the west coast of Korea in 2007, has been carried out to compute the oil spill velocity distribution in terms of flow depth. Friction loss due to the viscous flow and the discharge coefficient of crude oil with specific gravity SG = 0.85 and viscosity of $4-12cP(mPa{\cdot}s)$ at the temperature of $20^{\circ}C-100^{\circ}C$ are presented in terms of Reynolds number based on the results of high-resolution CFD modeling.

• Food Science and Preservation
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• v.18 no.3
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• pp.414-422
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• 2011

The optimum condition for phenolics contents extraction from purple sweet potato was 12 hrs. in 50% ethanol. The electron donating scavenging activities (DPPH), ABTS radical cation decolorization (ABTS) and antioxidant protection factor (PF) of Jami, Yeonjami and Shinjami were higher than general sweet potato, and thiobarbituric acid reaction substance (TBARs) was below 30%. The minimum inhibitory concentration (MIC) against Staphylococcus aureus and Escherichia coli on skin were each 5,000 and 2,500 ppm in all purple sweet potatoes, and MIC of Jami was the lowest as 2,500 ppm against Staphlococcus epidermidis. The whitening (tyrosinase inhibitory) activity of purple sweet potatoes was the highest as 62.5% and 48.7% in Jami water and ethanol extracts. The anti-inflammation (hyaluronidase inhibitory) activity of purple sweet potatoes was the highest as 25.3% and 94.4% in Jami water and ethanol extracts. The safety of cosmetic with Jam; extracts was assessed by various safety profiles. pH and viscosity change of essence for 90 days was not detected. Cosmetic was stable to temperature and light for 90 days. The result to measure changes of skin color and pore size of the skin was that an aged skin was more effective than young skin.

• Food Science and Preservation
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• v.18 no.6
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• pp.898-906
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• 2011

Physicochemical and physiological characteristics of red garlic were investigated in each of the four steps of its processing, and were compared with those of fresh and black garlic. With the progress in processing, the lightness value of the external and internal colors of the red garlic significantly decreased. The hardness was highest in the fresh garlic and lowest in the black garlic. During processing, the red garlic tended to become hard. The crudeprotein and ash contents were highest in the red garlic (step 4), but its moisture content was the lowest. The crudelipid content of the red garlic was lower than that of the fresh garlic. The pH of the red garlic showed little difference from that of the fresh garlic, but the black garlic was significantly, acidified. The acidity and pH contradicted each other : the black garlic had the highest acidity, and the acidity of the red garlic was within the low range. The fresh garlic had the lowest in reducing-sugar content, but such content was significantly increased in the red garlic and black garlic. Six kinds of organic acid were detected in the fresh garlic, and the same contents were also quantified in the red garlic until third step. In step 4, malic acid was not detected in the red garlic. Acetic and citric acid were only in the black garlic. S-allyl cysteine content of the red garlic was $18.05{\pm}0.53$ mg/100 g, similar to that of the black garlic ($19.43{\pm}0.50$ mg/100 g).

• Korean Journal of Plant Resources
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• v.28 no.2
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• pp.243-252
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• 2015

This study was performed to establish a production system for in situ and ex situ conservation of Elsholtzia minima Nakai, an endemic plant grown in Jeju Island. Moreover, this study aimed to identify root-growth characteristics according to the use of pre-treatment agents and seedling growth effect according to fertilizer application. The mean temperature was similar in greenhouse and vinyl-moist chamber, but air humidity was higher in vinyl-moist chamber than in greenhouse. After stem planting of Elsholtzia minima Nakai, initial root growth was observed after 10 days in greenhouse and after 7 days in vinyl-moist chamber. Root growth rate was more rapid in vinyl-moist chamber. Moreover, survival rate, root growth rate and root number was slightly higher in vinyl-moist chamber than in greenhouse, indicating that vinyl-moist chamber is more effective in plant growth. When pre-treatment agents were used to remove root growth-inhibiting substances, a higher root growth rate of more than 95% was found in pre-treatment groups, excluding the group treated with AgNO₃ at 77.5%. Thus, Elsholtzia minima Nakai is thought to have less root growth inhibitors. In the analysis of nitrogen application rate and Osmocote application by seedling container, a difference was found in survival rate and growth according to application rate and container conditions. When Osmocote, a slow release fertilizer, was applied to the soil surface around each culture container, survival rate and the growth of aerial and root parts were most favorable. Thus, Osmocote fertilizer is thought to be desirable for seedling propagation of Elsholtzia minima Nakai.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.405-411
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• 2007

This study was carried out to measure insoluble phosphorus fractions content fixed in different soil type and isolate a superior phosphate solublizing bacteria(PSB) producing free phosphate in citrus orchard soil. Distribution of insoluble phosphate fraction ordered Al-P>Ca-P>Fe-P in the investigated citrus orchards. Insoluble phosphate fraction such as Al-P, Ca-P, Fe-P were higher in volcanic ash than in non-volcanic ash soil. A PSB with high holo zone in PDA-P medium isolated from citrus orchard soil. This strain identificated by MIDI system as Bacillus sphaericus. The optimum growth of pH and temperature were at 4~5, $30^{\circ}C$, respectively. When Bacillus sphaericus cultured at $25^{\circ}C$, 150 rpm condition in LB broth medium included different phosphate. Bacillus sphaericus produced free phosphate in the culture broth medium from tricalcium-phosphate(207.0 ppm), aluminium phosphate(324.5 ppm) and hydroxyapatite(334.8 ppm) and Phosphatase activity of Bacillus sphaericus was higher at $35^{\circ}C$ culture condition than that of $25^{\circ}C$. Two type preparation inoculated Bacillus sphaericus made with carrier materials such as Bentonite, $CaCO_3$, Sodium alginate. Density of PSB in this preparation conserved at $10^5c.f.u.\;g^{-1}$ level during storage in different temperature condition for 7 month. It also showed that free phosphate produced at PDA-P medium.

• Journal of the Korean Institute of Gas
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• v.25 no.5
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• pp.78-87
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• 2021

This paper analyzes the range and attributes of the traffic information service between domestic public institutions and private companies, and suggests the possibility of joint application of node-link information for each company and the possibility of joint use of private traffic information. For this purpose, the present condition and attributes of domestic and foreign traffic information node-links (link length, node ID number, U-turn information, lane information, left turn information, right turn information, etc.) were analyzed. The analysis targets, the node-link of the national standard node and the two companies were analyzed. The area of the experiment was selected in Jongno-gu, Seoul, where standard-link information is complex, traffic volume is high, and various standard-links exist. The experiment was conducted by comparing and analyzing the traffic information attributes of three types of node-links and performing node-links overlapping matching (utilizing encoding_decoding method), and the possibility of matching node-links and attributes of different specifications was analyzed using Open LR technique.

• Resources Recycling
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• v.30 no.1
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• pp.44-52
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• 2021

This study investigated the effect of the type of alkaline precipitant used on the synthesis of lithium hydroxide by examining the behavior of lithium hydroxide produced using lithium sulfate recovered from a waste lithium secondary battery as a raw material. The double-replacement reaction (DRR) process was used to remove the impurities contained in the lithium salt precursor of lithium sulfate and to improve the efficiency of the synthesis of lithium hydroxide. The experiment was conducted by control the molar ratio of the precursor ([Li]/[OH]), the reaction temperature, and the composition of the alkaline precipitant (KOH, Ca(OH)2, Ba(OH)2) used for the production of highly-crystalline lithium hydroxide. A secondary solid-liquid separation was performed following the reaction to remove the impurities generated, and the purified aqueous solution of lithium hydroxide was evaporated to remove the moisture and obtain the product as a powder. The crystallinity and synthesis behavior of the product were examined.

• Journal of the Korea Convergence Society
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• v.12 no.7
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• pp.61-67
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• 2021

The purpose of this study was to investigate the colors of spectacle lenses that would be effective in blocking blue light among various colors so that the damage caused by blue light could be conveniently reduced even in daily life and when filling with dental light-curing resin. Each color dye of orange, brown, gray, yellow, red, and rosa was dissolved in an individual container of a spectacle lens tinting machine, and 6 uncolored spectacle lenses were immersed in a temperature of 90℃ for 1 hour to color. As a result of comparing the blue light transmittance of the colored spectacle lens and the tip for the photopolymerizer, the blue light transmittance of the orange colored lens was 0.82%, and the blue light blocking effssect was the best. Brown and gray tinted lenses had excellent blue light blocking rate, but it was difficult to recognize objects through the lens due to the high tinted concentration, and yellow tinted lenses were found to be effective when the tint was similar to the tip. The blue tinted lens had a blue light transmittance of 15.10%, which was lower than other tinted lenses. The results of the experimental study are expected to be helpful in recognizing the blue light transmittance by spectacle tinted lenses of various colors and making efforts to select the appropriate blue light blocking lens color and block harmful blue light stimuli.

• Clean Technology
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• v.25 no.1
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• pp.7-13
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• 2019

Recently, attention has been paid to obtaining bio-polyols from renewable resources. Successful use of these natural ingredients successfully produced in the industry for the synthesis of various polyurethanes is a very important task. In this study, a series of dimethylformamide (DMF) based polyurethanes were synthesized from methylene diphenyl diisocyanate (MDI)/1, 4-butanediol and bio-polyol (polytrimethylene ether glycol based on 1, 3-propanediol : B-POL)/polyester polyol (polyadipate diol based on 1,4-butandiol : H-PET). The effect of different ratio of bio-polyol (B-POL)/polyester polyol (H-PET) on the physical properties of polyurethane was investigated. As the B-POL content in B-POL/H-PET mixture increased, the glass transition of soft segment (Tgs) and tensile strength of polyurethane decreased, however, the elongation at break and tear strength increased. On the other hand, artificial leather was produced by wet process using synthesized DMF-based polyurethanes. It was found that there was almost no difference in the effect of the B-POL/H-PET composition on the average size and density (the number of cells per unit volume) of the porous cells formed in artificial leather. These results show that there is no problem in using bio-polyol (B-POL) based polyurethane for artificial leather produced by wet process.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.313-320
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• 2018

In the spring of 2018, opened-flowers of fruit trees were frozen to death due to abnormal low temperature around Jeonbuk Province and southern Gyeonggi Province areas. In the 2000s, abnormal weather is observed all over the world very frequently. As a consequence, various sectors of the society suffer from economic damage and negative effects of the abnormal weather. Moreover, recent global climate change is believed to increase the incidence of extreme weathers, which are out of the normal range of the local climate. It is necessary to identify these abnormal weather phenomena accurately and analyze the effects of them on crops in order to understand the effects of them on crop yields. This study projected the trend of the low-temperature occurrence in the future by predicting the changes in future flowering dates and quantifying the temperature distribution after flowering using climate change scenarios. This study targeted areas actually producing a major portion of pear, peach, and apple in South Korea. The results of this study predicted that the flowering dates of these fruits will be approximately 20 days earlier than the current normal year in the future (2071-2100) for the study area. Moreover, it was found that the distribution of low temperature would vary by fruit type and region to some degree. The results of this study present only a portion of fruit trees cultivars grown in South Korea. It was expected that, when this approach is applied to various crops and fruit trees, it will be possible to contribute to preparing countermeasures for climate change in the agricultural sector.