• Resources Recycling
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• v.26 no.6
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• pp.45-49
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• 2017

Most Waste slurry is produced in the process of silicon manufacturing for semiconductor industry, containing silicon (Si) and silicon carbide (SiC). Waste slurry is simply stored with solidifying by cement or buried. On the other hand, it was suggested in this study that the waste slurry should be used for heating source as supplementary material in steel making process. The waste slurry was refined and pulverized, which was recycled into SiC-based sludge briquette. Chemical composition for SiC-based sludge briquette was analyzed and the feature of heating source was observed in accordance with the injection time and input amount. As a result, SiC-based sludge briquette in terms of low cost and high efficiency had an effect on increasing liquid steel temperature in steel making plants.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.139-142
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• 1984

Effects of irradiation on the microbial growth and physicochemical properties of garlic powder were investigated during 3 months storage. Total bacteria and coliform group of garlic powder were $4.74{\times}10^{4}$ and $5.0{\times}10^{3}$ per g, respectively and irradiation of 5 kGy and 7 kGy could sterilize coliform group and total bacteria, respectively. $D_{10}$ value of total bacteria was 3.34 and no microorganisms were grown in 5 to f kGy irradiated groups after 3 months storage at $30{\pm}1^{\circ}C$. Moisture, sugars and pH of garlic powder were not remarkably changed during storage but pyruvic acid content was slightly decreased with storage period. Color difference of garlic powder after 3 months storage could not be distinguished by naked eye, but a slight change was recongized by the mechanical measurement.

• Journal of the Korea Concrete Institute
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• v.13 no.2
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• pp.114-122
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• 2001

The purpose of this study was to manufacture sintered lightweight aggregate using paper sludge ash and to evaluate the qualities of the aggregate according to various mix proportions, conditions of pelletization and sintering. The paper sludge ash alone, due to its mineral and chemical compositions could not gain suitable expansion and strength. Hence, it was essential to add mineral additives such as clay, fly ash etc. The optimum muting ratio range determined in this study is as follows , paper sludge ash 30∼50 %, clay 30∼50 %, fay ash 0∼40 %, Paper sludge 0∼10% and hematite 2∼3 %(for manufacturing lightweight aggregate both for non-structural and structural concrete). It was possible to manufacture various lightweight aggregate whose dry specific gravity ranged about from 0.6 to 1.4 by using this optimum mixing ratio. From the test results of the qualities of aggregate, it showed that the 10% granules crushing value test and water absorption percentage ranged about 5∼10 ton and 10∼20%. Thus, it was favorably comparable to those of the imported aggregate. The manufactured lightweight aggregate could be used for structural concrete and non-structural concrete.

• Korean Journal of Oriental Medicine
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• v.15 no.3
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• pp.1-10
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• 2009

Samhwajahyangyakbang, a medical book of Hyangyak which was presumed to be published by Samhwaja in the late Goryeo dynasty, became the original source of Hyangyakganibang. As Hyangyakganibang became the original source of Hyangyakjesengjipseongbang which was supplemented to be Hyangyakjipseongbang, Samhwajahyangyakbang is a fundamental book which is the original source of Hyangyak medical books such as Hyangyakganibang and Hyangyakjipseongbang in the late Goryeo and the early Chosun dynasty. I restored the articles of Samhwajahyangyakbang, mainly focusing on the remaining articles in Hyangyakjipseongbang, followed by supplementing some other remaining articles with the help of , a database of old medical books, and then, recorded and discussed the results in the paper. 1. The remaining articles of Samhwajahyangyakbang were found in Hyangyakjipseongbang, Uibo and Uibanghappyeon. Among them, there is a prescription which is not overlapped in Uibanghappyeon. 2. The classification system of Hyangyakjipseongbang was alternatively adopted due to the absence of classification or table of contents in Samhwajahyangyakbang. 3. There are a total number of 152 articles in the restored Samhwajahyangyakbang and 151 articles out of the total number have been restored from Hyangyakjipseongbang. There are 5 articles which remain as notes in the citations of other books in Hyangyakjipseongbang. 4. There are a total number of 246 prescriptions in the restored Samhwajahyangyakbang. 5. Even though Samhwajahyangyakbang is a concise medical book, it is one of the core medical books which are cited in Hyangyakjipseongbang. In addition, it is the most frequently cited in Hyangyakjipseongbang among the Korean medical books. It implies that the compilers of Hyangyakjipseongbang considered Samhwajahyangyakbang the most valuable book among the Hyangyak medical books. It is speculated that such results could be achieved because Samhwajahyangyakbang was very popular in those days and its' printing quality was also good. On the contrary, the number of citations of Hyangyakgugeupbang is much less than that of Samhwajahyangyakbang. It is presumed that Hyangyakgugeupbang could not be distributed widely not because it was less valuable but because its' printing quality was poor.

• Journal of the Korea Society of Computer and Information
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• v.26 no.12
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• pp.213-220
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• 2021

As the coronavirus disease(COVID-19) pandemic is declared and the number of confirmed cases and deaths increases in countries around the world, the world is gripped with fear. Therefore, in this study, psychological factors of infection prevention behaviors of firefighters and maritime police officers were analyzed based on the Health Belief Model. Although there was no significant difference in the COVID-19 prevention behaviors between the two groups, there was a significant positive correlation between the perceived disease infection possibility, perceived severity, and perceived benefits in the general characteristics and the COVID-19 prevention behaviors. There was no significant difference with perceived obstacles. This study is of great significance in that it is the first analysis of firefighters and maritime police officers as a health belief model, and can be used as basic data for the implementation of new infectious disease prevention actions.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.294-299
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• 2020

Based on the combined results of field surveys and analyses of the road structure and traffic flow, we propose a new plan for reducing roadside non-point pollution in the Paldang Water Source Protection Zone. The results show that the soil surrounding the roads in Paldang is highly permeable, which mitigates the need for filtration facilities. Roads flanked by steep slopes are found to facilitate the reduction of non-point roadside pollution through vegetation and soils along road slopes without the need for pollution reduction facilities. These results highlight the need for a flexible roadside non-point pollution reduction plan for roadside non-point pollution, which can be tailored to compliment relevant regulations and design standards after analyzing the characteristics of the target road.

• Transactions of Materials Processing
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• v.31 no.2
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• pp.51-56
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• 2022

In this study, finite element analyses were performed by applying a stress ring and split die design to relieve the tensile stress acting on the die due to high surface pressure during warm-closed forging. The applied material was a yield-ratio-control-steel (YRCS). It was used without quenching or tempering after forging. In the case of stress rings design, the number of stress rings and the tolerance for shrink fit were different. Vertical and horizontal splits were applied for insert die split design. Case 5 die with three stress rings, 0.2 % shrink fit tolerance, and vertical split was selected as an effective die design for tensile stress reduction. Based on die stress reduction analyses, Case 5 die for warm-closed forging was produced and smooth forgeability was secured, making it possible to manufacture forging product of yoke with the required geometry. In addition, controlled cooling using warm forging heat was applied to secure mechanical properties of yokes. When oil cooling was used for direct controlled cooling after warm-closed forging, a relatively uniform Rockwell hardness distribution and high mechanical properties could be obtained.

• Transactions of Materials Processing
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• v.32 no.5
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• pp.239-246
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• 2023

To reduce the forming load due to the temperature drop, during the hot forging process, a reheating hot forging process design is required that to repeat heating and forging. However, if the critical strain required for recrystallization is not induced during forging and grain growth becomes dominant due to the reduction in dislocation density due to repeated heating, the mechanical properties may deteriorate. Therefore, in this study, Inconel 706 alloy was applied, and the grain refinement behavior was comparatively analyzed according to the number of reheating times and effective strain during reheating hot forging process. Reheating was carried out with a total compression rate of 40% up to 4 times. The Inconel 706 compression test specimens heated once showed finer grains as the effective strain increased due to the dynamic recrystallization phenomenon. However, as the number of heating increases, grain refinement was observed even in a low effective strain distribution of 0.43 due to static recrystallization during reheating. Moreover, grain growth occurs at a relatively low effective strain of 0.43 when the number of reheating is four or more. Therefore, it was effective to apply an effective strain of 0.43 or more during hot forging to Inconel 706 in order to induce crystallization through grain refinement and improve the properties of forged products. In addition, we could notice that up to three reheating times condition was appropriate to prevent grain growth and maintain fine grain size.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4D
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• pp.539-543
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• 2008

The Directional sign system in Korean high speed railway stations has a lot of problems. For an example, It lacks of consistency in the shape or allocation. Also, the signs do not match with the actual directions sometimes. Last but not least, the view is blocked by the other signs such as advertisement or other barriers. We suggested the methods to standardize the sign systems that include visibility, accuracy, consistency, and simplicity. First, we categorized signs into directional signs, locational signs, and infomational signs. Then, we examined the actual high speed railway stations in Korea to learn the real situation. Finally, we suggested the methods to standardize the sign systems considering the factors that are visibility, accuracy, consistency, and simplicity.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.5
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• pp.1352-1363
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• 2015

This study was carried out to investigate the characteristics of the dependent variables depending on the condition changes of independent variable of the operation and the material during the production of collets added with rice and dried shrimp by using single extruder to utilize as basic data for the manufacture of extrusion collets. A total of 7 independent variables were set up as a raw, 20, 40 and 60 mesh for the powder particle size of rice; 12, 14, 16 and 18% for the moisture content of rice; 2, 4, 6 and 8% for the addition amount of dried shrimp; 90, 95, 100 and $110^{\circ}C$ for the barrel temperature; 210, 280 and 340 rpm for the screw speed; 4, 6, 8 and 10 mm for the discharge port diameter; 30, 40, 50 and 60 kg/h for the input amount of the mixed material. The characteristics of the dependent variables including puffing ratio, moisture content, lightness, uniformity, productivity of collets was to be studied by changing the conditions of the independent variables. As a results of this study, 20 mesh of powder particle size of rice, 14% of moisture content of rice, 4% of addition amount of dried shrimp, $100^{\circ}C$ of barrel temperature, 280 rpm of screw speed, 6 mm of discharge port diameter and 50 kg/h of input amount of mixed material were found to be the most preferable over other independent variables for the production of extrusion collets. In conclusion, it is necessary to set the independent variable in order to produce the high quality collets added with the rice as the main raw material and dried shrimp as the sub-materials.