• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.247-251
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• 2008

Degradation behavior in the seawater of Tongyeong, Incheon, Kunsan and Hongsung was explored for Mater-Bi$^{(R)}$, poly(3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV), poly(butylene succinate-co-butylene adipate) (PBSA) and polycaprolactone (PCL) which can eventually be used for various fishery tools. Acinetobacter lwoffu/junii and Shewanella algae/putrefaciens inhabited all the seawater samples. Eikenella corrodens was also detected in all the seawater samples, although identified with poor confidence by VITEK system. Mater-Bi$^{(R)}$ was degraded faster than PHBV, PBSA and PCL in the seawater in contradiction to the degradation behavior in soil environment. The seawater retrieved from Incheon exhibited the most elevated activity for the plastic degradation, which may be partly ascribed to the largest number of total viable counts.

• The Research Journal of the Costume Culture
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• v.27 no.2
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• pp.169-180
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• 2019

The purpose of this study is to offer basic data on cosmetics by investigating college women's purchasing and use behaviors regarding cosmetics according to their experience with side effects. A questionnaire was administered to 351 college women in the Seoul and Kyoung-in areas. The data were analyzed with SPSS Statistics V22.0 using frequency, ${\chi}^2$-test, and t-test. The results are as follows. First, 72.6% of surveyed women reported experiencing side effects from cosmetics. The largest side effects were acne and boils, and the primary ways of coping with these side effects were discontinuing use and using other products. Second, the group that experienced cosmetics' side effects used brands that were more expensive and eco-friendly than the group without side effects. Third, the group that experienced side effects continued to use the product more than the group without side effects. The primary reason for continued use was efficacy, and the reasons for discontinued use were efficacy and curiosity. Fourth, the side-effects group proactively identified cosmetics ingredients more than the non-side-effects group. Specifically, they checked the major components, the function, and for any hazardous ingredients. Fifth and finally, 98.3% of survey respondents purchased and used functional cosmetics. The group that had experience with side effects used more functional cosmetics than the group without side effects.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.1295-1302
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• 2021

The study aims to investigate the antecedents affecting purchase intention in the category of green skincare products. Many studies have used the theory of planned behavior to investigate factors affecting intention to purchase products in general. This paper not only retests the influences of attitude, subjective norm, perceived behavioral control on the intention to buy eco-friendly skincare products but also suggests a new antecedent - environment knowledge of purchase intention. More importantly, this study is the first to propose the moderating effect of country of origin and product knowledge on the relationship between attitude and purchase intention. This study employs a sample of 350 female customers from 18 to 39 years old in Ho Chi Minh City. The research applies the Multiple Linear Regression to analyze the proposed hypotheses in the conceptual framework and results in significant outcomes. The result shows that attitude is the most influential factor then, subjective norm, perceived behavioral control and environmental knowledge. Most importantly, the findings of this study suggest that product knowledge is found to moderate the effect of attitude on purchase intention. The finding of moderating effect is a new contribution to the literature and future research can be carried out to validate this result.

• Journal of Powder Materials
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• v.28 no.2
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• pp.91-96
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• 2021

Rare earth magnets with excellent magnetic properties are indispensable in the electric device, wind turbine, and e-mobility industries. The demand for the development of eco-friendly recycling techniques has increased to realize sustainable green technology, and the supply of rare earth resources, which are critical for the production of permanent magnets, are limited. Liquid metal extraction (LME), which is a type of pyrometallurgical recycling, is known to selectively extract the metal forms of rare earth elements. Although several studies have been carried out on the formation of intermetallic compounds and oxides, the effect of oxide formation on the extraction efficiency in the LME process remains unknown. In this study, microstructural and phase analyses are conducted to confirm the oxidation behavior of magnets pulverized by a jaw crusher. The LME process is performed with pulverized scrap, and extraction percentages are calculated to confirm the effect of the oxide phases on the extraction of Dy during the reaction. During the L ME process, Nd is completely extracted after 6 h, while Dy remains as Dy₂Fe₁₇ and Dy-oxide. Because the decomposition rate of Dy₂Fe₁₇ is faster than the reduction rate of Dy-oxide, the importance of controlling Dy-oxide on Dy extraction is confirmed.

• Journal of Ocean Engineering and Technology
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• v.36 no.4
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• pp.211-216
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• 2022

Since liquefied natural gas (LNG) is imported in a liquid state of about -162℃ to increase transportation efficiency in Korea, it must be vaporized in a gaseous state to supply it to consumers. Among them, ambient air vaporizer (AAV) has caught attention due to eco-friendly and low costs characteristics. However, there is a disadvantage that the performance of the heat exchanger is deteriorated due to frost due to mist and icing when used for a long time. In this paper, frost generation model in AAV vaporizer was investigated with numerically to examine utilizing the vaporizer performance with the frost generation behavior. The frost generation behavior of AAV vaporizers was examined with humidity, fin characteristic, and temperature effects. As for the LNG discharge temperature, the 12 fin vaporizer showed the highest discharge temperature when the atmospheric temperature was 25℃, and the 8 fin vaporizer had the lowest LNG discharge temperature when the atmospheric temperature was 0℃. In the case of frost formation, in the case of the 12 fin vaporizer, it was formed the most at the atmospheric temperature of 25℃, and the least was formed in the vaporizer at the 0℃ condition of the atmospheric temperature of 8 fins.

• Advances in concrete construction
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• v.13 no.3
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• pp.233-242
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• 2022

An attempt is made to develop an eco-friendly concrete with ground granulated blast furnace slag (GGBS) and pond ash as partial replacement materials for cement and fine aggregate, respectively without compromising the strength and durability. Sixteen concrete mixes were developed by replacing cement and fine aggregate by GGBS and pond ash, respectively in stages of 10%. The maximum replacement levels of cement and fine aggregates were 50% and 30% respectively. Experimental results revealed that the optimum percentage of GGBS and pond ash replacement levels were 30% and 20% respectively. The optimized mix was used further to study the flexural behavior and durability properties. Reinforced Concrete (RC) beams were cast and tested under a four-point bending configuration. Also, the specimens prepared from the optimized mix were subjected to alternate wet and dry cycles of acid (3.5% HCl and H₂SO₄) and sulphate (10% MgSO₄) solutions. Results show that the optimized concrete mix with GGBS and pond ash had a negligible weight loss and strength reduction.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.793-802
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• 2023

The aim of this study analyzed changes in dietary habits and lifestyles before and after COVID-19 targeting adolescents, using the food consumption behavior survey (2019 vs 2021). In the change in health-related factors, height decreased overall, and a significant difference was especially evident in males. Awareness that functional foods and eco-friendly foods contribute to health has increased. Among the results of dietary behavior, the frequency of skipping breakfast showed that the rate of not skipping breakfast and the rate of skipping breakfast more than 5 times increased at the same time(p=0.019). The rate of eating out decreased significantly after COVID-19, and it was analyzed that schools and school cafeteria, as well as Street carts or restaurants and academy, all increased significantly as places where snacks were not consumed. In order to analyze changes in food-related lifestyle, it was grouped into convenience-seeking, quality/safety-seeking, taste-seeking, and health/safety-seeking. 'Small packaged or pre-processed products' decreased. On the other hand, items such as 'Safety rather than price when choosing food' and 'Don't eat food that could go bad' improved. 'Tend to eat regularly' was higher than 2021 compared to 2019. Also 'Tend to purchase HACCP and GAP-certified products' are increased. Because of COVID-19 changes in lifestyle have affected the diet of adolescents. The results of this study suggest that it can be used as a guideline establishment and nutrition counseling material for the formation of correct eating habits for adolescents in the future pandemic era.

• Geomechanics and Engineering
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• v.25 no.1
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• pp.41-48
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• 2021

In cold regions, the integrity of the infrastructures built on weak soils can be extensively damaged by weathering actions due to the cyclic freezing and thawing. This damage can be mitigated by exploiting soil stabilization techniques. Generally, ordinary Portland cement (OPC) is the most commonly used binding material for investigating the chemo-hydromechanical behavior. However, due to the environmental issue of OPC producing a significant amount of carbon dioxide emission, calcium sulfoaluminate (CSA) cement can be used as one of the eco-sustainable alternatives. Although recently several studies have examined the strength development of CSA treated sand, no research has been concerned about CSA cement-stabilized sand affected by cyclic freeze and thaw. This study aims to conduct a comprehensive laboratory work to assess the effect of the cyclic freeze-thaw action on strength and durability of CSA cement-treated sand. For this purpose, unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) tests were performed on the stabilized soil specimens cured for 7 and 14 days which are subjected to 0, 1, 3, 5, and 7 freeze-thaw cycles. The test results show that the strength and durability index of the samples decrease with the increase of the freeze-thaw cycles. The loss of the strength and durability considerably decreases for all soil samples subjected to the freeze-thaw cycles. Overall, the use of CSA as a stabilizer for sandy soils would be an eco-friendly option to achieve sufficient strength and durability against the freeze-thaw action in cold regions.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.4
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• pp.173-187
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• 2019

Based on the theory of planning behavior, the purpose of this study was to validate the path to consumers organic bakery product purchasing process, and moderating effect of price sensitivity. The improvement of national income and changes in diet due to economic growth began to increase consumption of organic and eco-friendly farm products, and thus products using organic materials began to be released in bakeries. Thus, it was necessary to understand consumer awareness and purchasing processes for organic bakery products. Specifically, the study examined the structural relations among purchase reasons, purchase motives, and purchase behavioral intention of organic bakery products. A survey was conducted in May 2019 from adults who had experience purchasing organic bakery products in Seoul metropolitan area, and 327 responses were used for data analysis. The findings of the study showed that consumers' interests in health, food safety, and environment had positive effects on their attitudes, subjective norm, and perceived behavioral control toward organic bakery products, while their interests in organic products did not have an effect on perceived behavioral control. There were significant differences in the purchasing process of organic bakery products according to their price sensitivity. The study suggests that the correct delivery of information on organic ingredients and the price policies available to many consumers will contribute to the revitalization of organic bakery products.

• Elastomers and Composites
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• v.53 no.3
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• pp.175-180
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• 2018

Solution-styrene-butadiene rubber (SSBR) composites were manufactured using four kinds of fillers: silica-silane coated carbon black (SC-CB) hybrid, starch-SC-CB hybrid, pure silica, and pure starch. The influence of filler type on the mechanical properties of the rubber matrix was studied in this work. SC-CB was prepared by silane-graft-coating using vinyl triethoxy silane and carbon black, which enhanced the dispersion effect between the rubber matrix and the filler, and improved the mechanical properties of the compounds. The morphology of the composites was observed by field-emission scanning electron microscopy (FE-SEM). The thermal decomposition behavior of the composites was determined by thermogravimetric analysis (TGA), and the crosslinking behavior of the composites was tested using a rubber process analyzer (RPA). The hardness, tensile strength, swelling ratio, and gas transmittance rate of the composites were evaluated according to ASTM. The test results revealed that with the addition of SC-CB, the hybrid fillers, especially those blended with silica, showed a better reinforcement effect, the highest hardness and tensile strength, and stable thermal decomposition behavior. This implies that the silica-SC-CB hybrid filler has a notable mechanical reinforcement effect on the SSBR matrix. Because of self-crosslinking during its synthesis, the starch-SC-CB hybrid filler produced the most dense matrix, which improved the anti-gas transmittance property. The composites with the hybrid fillers had better anti-swelling properties as compared to the neat SSBR composite, which was due to the hydrophilicity of silica and starch.