• Journal of the Korean Society for Heat Treatment
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• v.14 no.5
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• pp.297-303
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• 2001

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.367-375
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• 2009

Recently, more focus is shift to imbalances in aggregate market supply and demand and an exhaustion of natural resources. In this situation, Electric arc furnace oxidizing slag (EAF slag) has high application possibility as aggregate for concrete due to similar property with general aggregate. However, it is inherent the problem which causes pop-out by free-CaO contained in slag In this study, we've got the plan to assure the chemical stability of EAF slag, and then experimentally tested the mechanical performance and durability for the fine aggregate used EAF slag. On this test result, we suggest the application plan. At the result of this study, it shows that EAF slag would reduce the surface defect such as pop-out due to natural aging for the fixed hour and adjustment the grain size of EAF slag. And mechanical performance and durability according to the replacement rate of concrete service, were revealed more than equal or equal compare to general aggregate. Hereafter, quality control must precede not to impede the beauty of concrete surface as assure the safety for aging and processing. And, to establish the environmental resource recycling system for by-products of steel, it should be made development of various application and guideline of quality control for the EAF slag aggregate. Moreover, it must be constantly studied all kind of engineering performance and durability for related to this study.

• Journal of the Korea Institute of Building Construction
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• v.18 no.4
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• pp.321-327
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• 2018

Blast furnace slag has been actively used as a substitute for cement in the construction field with high value-added through resource recycling research. However, most of the slag cannot find a clear recycling purpose. This is because some slags contain unstable materials and are used for road-use asphalt and embankment, which are low value-added materials. Electric arc furnace reduction slag(ERS) has been reported to contain a large amount of unstable free CaO due to deoxidation and component adjustment. In this study, free CaO of ERS which is generated in Korean steelmakers is quantitatively evaluated by using ethylene glycol method. As a result of free CaO quantitative evaluation of ERS, it was confirmed that there is a big difference according to the location of each field. In addition, ERS generally existed in powder form as undifferentiated characteristics, but it was confirmed that free CaO content was different due to hydration product in aggregate form due to water treatment. In addition, free CaO is an amorphous material and its crystallization characteristics are different due to the influence of temperature when it is cooled. ERS requires a long-term aging period as it contains a lot of free CaO.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.133-142
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• 2014

Recently, more focus is shift to imbalances in aggregate market supply and demand and an exhaustion of natural resources. In this situation, Electric arc furnace oxidizing slag (EAF Slag) has high application possibility as aggregate for concrete due to similar property with general aggregate. In this study, We've got the plan to assure the chemical stability of EAF Slag, and then experimentally tested the mechanical performance and durability for the fine aggregate used EAF Slag. On this test result, we suggest the application plan. At the result of this study, it shows that EAF slag would reduce the surface defect such as pop-out due to natural aging for the fixed hour and adjustment the grain size of EAF Slag. And mechanical performance and durability according to the replacement rate of concrete service, were revealed more than equal or equal compare to general aggregate. Hereafter, quality control must precede not to impede the beauty of concrete surface as assure the safety for aging and processing. And, to establish the environmental resource recycling system for by-products of steel, it should be made development of various application and guideline of quality control for the EAF slag aggregate. Moreover, it must be constantly studied all kind of engineering performance and durability for related to this study.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.4
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• pp.313-319
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• 2015

This study relates to an investigation into semi-dry manufacturing process of BP sludge based on non-heating production method. In this study, we conducted a research into reduction of water content ratio which arose from mixture of BP by-products of high water content ratio(50% or higher) with industrial by-products to use such BP by-products as construction materials in large quantity. We measured the reduction rate of water content ratio at the feeding ratio of water content reduction agent(1:0.5) in BP by-products. The results showed that water content ratio was the lowest with 18.5% in the mixture of PA+CFA(1:0.5). Moreover, water content ratio ranged between approximately 9.2% and 11.4% at the age of 1 day to 2 days at the aging temperature of $20-30^{\circ}C$, suggesting that the water content ratio was in the range within 10% which was a level suitable for use as construction material in this study. Meanwhile, we compared and evaluated the physical properties of non-heated BP by-products based on post-aging pulverization method. The results showed that there was no significant difference, depending on pulverization method. When production efficiency and economic feasibility were taken into consideration, it was found desirable to use fine particle pulverizer or pin mill enabling continuous production.

• Journal of the Mineralogical Society of Korea
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• v.32 no.3
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• pp.213-222
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• 2019

Birnessite (birnessite, $7{\AA}$ manganate, ${\delta}-MnO_2$) is a major mineral comprising manganese nodule. Various synthetic methods have been studied and evaluated because it can be used as an ion exchange agent and a battery recharging material. However, it is difficult to obtain a single birnessite phase because it does not have a stoichiometric chemical composition. Feitknechtite (${\beta}-MnOOH$) is formed as an intermediate product during birnessite synthesis and in this study, the transition of this phase to birnessite was compared by using XRD and SEM. Two different methods, Feng et al. (2004) and Luo et al. (1998), based on redox reaction were used. It was possible to obtain the impurity-free birnessite for the sample aged 60 days at $27^{\circ}C$ by Feng et al. (2004) method and 3 days at $60^{\circ}C$ by Luo et al. (1998) method. The phase transition rate of the feitknechtite phase was slower in the case of $Mg^{2+}$ doped birnessite which was synthesized by Luo et al. (1998) method, and almost single phase almost single phase birnessite was identified at high temperature. Crystal surface and morphology also confirmed the difference between the samples synthesized by two methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.263-272
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• 2021

This study investigated the oral health knowledge and educational needs of adults by life cycle. We aimed to provide basic data for developing oral health education plans for well -aging. The survey was conducted online and through mobiles by Gallup Korea during February 2021. A total of 319 adults over the age of 19 were surveyed. The study aimed at investigating the general characteristics, the quality of life-related to oral health, knowledge of oral health, and the need for well-aging education. The PASW Statistics ver 18.0 statistical program was used for data analysis. The analysis of the data suggests that prevention was the highest priority among all age groups. Furthermore, there was a difference in the perceived educational need among different age groups. The cause of the youth, the treatment of the middle-aged and the elderly were significantly related to oral and systemic disease. The need for education related to oral diseases was ranked in the order of aches, bad breath, periodontal diseases, and tooth discoloration. For information, the subjects reached out to the internet, dental and medical institutions, and public health centers. The teaching methods experienced by those surveyed included lectures combined with experience, videos, and expert lectures. We believe that this study can be used to develop an education plan that reflects the needs of the subjects when conducting life cycle education for well-aging.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.343-352
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• 2021

The purpose of this article is to study the negative factors reflected in the will and the factors of well aging as an alternative. The survey data was 36 wills published in the media such as newspapers and broadcasting between 2008 and 2020. As a result, various aspects of negative factors were found in youth wills between the ages of 13 and 34. In middle-aged wills between the ages of 35 and 49, female was not found. The negative factors in the socio-economic aspects were remarkable in the wills of adulthood between the ages of 50 and 64. All the writers of wills over the age of 65 were women, and their writings were strongly linked to the spiritual side. In view of these results, the will explored in this study can paradoxically become a proposal for a complete life. The will is a record with the potential of well aging. Sources of the suicide note included daily newspaper, broadcasting and local media. This study analyse the age and gender and the negative factors reflected in the will, by using the physical aspect, the mental aspect, and the socio-economic aspect as the methodology. In addition, the frequency of words and expressions exposed in the will were analyzed and keywords were created in word cloud.

• Journal of Digital Convergence
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• v.19 no.4
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• pp.205-215
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• 2021

This study was conducted to provide basic data to establish health promotion and chronic disease management education programs and educational plans for well-aging by investigating the educational needs for health promotion and chronic disease management by life cycle. This is a descriptive correlation research study, and collected and analyzed through a structured questionnaire targeting 330 adults over 19 years of age registered at Gallup Korea. The results of the study were perceived health status 3.11 points (SD=.72), health promotion behavior 2.27 points (SD=.47), and health-related quality of life 0.92 points (SD=.10). Health-related quality of life was found to have a positive correlation with perceived health status (r=.472, p<.001) and health promotion behavior (r=.122, p<.026). The priority of educational needs and contents for health promotion and chronic disease management was the highest in chronic disease management. There was a significant difference according to the life cycle (p=0.001), and it was found that the mature stage was more likely to be aware of the level of knowledge, the need for education, and the willingness to participate in education compared to the youth. Through the results of this study, it is necessary to develop a comprehensive customized program that is subdivided according to the life cycle when developing health promotion and chronic disease management education programs for well-aging.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.299-309
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• 2022

YouTube videos secure the latest trends in the field and provide viewers' preferences and non-preferences. This study analyzes the discussion of death in recent YouTube videos and explores the relationship between life, well-dying, and well-aging. The purpose of this study is to contribute to the establishment of a healthy life for Koreans by exploring relevance. The survey period and target are 13 videos uploaded on YouTube from 2019 to 2021. As a result of the investigation, it was possible to encompass 25 speakers who were discussing death centered on doctors. Video speakers in charge of various areas conducted various discussions on death from the perspective of experts. The key points are the true value of life, death that you don't need to fear, the importance of hope, the naturalness of death, etc. 11 expert perspectives are measured into 4 types based on 4 criteria: life, death, well-aging, and well-dying. Despite the limitations of studying 13 extracted at a specific time, this study revealed that YouTube videos are a place for free communication. It can contribute in part to maintaining and improving the health of our lives in the future and researching convergence.