• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.67-73
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• 2020

In this study, the self-healing performance of mortar beams containing self-healing materials was evaluated through experiments. Normal mortar beams and self-healing mortar beams were used In the experiments. The self-healing performance was evaluated by comparing the mortar compressive strength, member strength, and self-healing effects of cracks. The experimental results showed that the compressive strength of mortar containing self-healing material was smaller than that of normal mortar, but the ratio of 118 days compressive strength to 28 days compressive strength was the same. The member strength tended to increase with increasing curing period. In normal mortar specimens, the member strength did not recover even if the curing period increased, but the strength of the self-healing mortar specimens tended to recover as reaction products were produced. The crack width tended to decrease after the healing periods in both specimens, but the reaction product was observed only in the self-healing mortar specimens.

• Earthquakes and Structures
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• v.16 no.6
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• pp.727-741
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• 2019

A reinforced concrete water tank is a typical functional liquid storage structure and cracks are the greatest threat to the liquid storage structure. Tanks are readily cracked due to seismic activity, thereby leading to the leakage of the stored liquid and a loss of function. In order to study the effect of cracks on liquid storage tanks, self-healing and leakage tests for bending cracks and through cracks in the walls of a reinforced concrete water tank were conducted. Material performance tests were also performed. The self-healing performance of bending cracks in a lentic environment and through cracks in a lotic environment were tested, thereby the self-healing width of bending micro-cracks in the lentic environment in the short term were determined. The through cracks had the capacity for self-healing in the lotic environment was found. The leakage characteristics of the bending cracks and through cracks were tested with the actual water head on the crack. The effects on liquid leakage of the width of bending cracks, the depth of the compression zone, and the acting head were determined. The relationships between the leakage rate and time with the height of the water head were analyzed. Based on the tests, the relationships between the crack characteristics and self-healing as well as the leakage were obtained. Thereby the references for water tank structure design and grading earthquake damage were provided.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.10-19
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• 2016

The objective of this study is to investigate the self-healing properties of ternary blended cement(TBC) paste made with OPC, GGBFS and FA. The influence of OPC-GGBFS-FA on the self-healing ability of ternary blended cement paste was researched by ultrasonic pulse velocity(UPV) measurement. The TBC paste with GGBFS-FA replacement ratios of 20%, 40% and 60% were prepared having a constant water-cementitious materials ratios os 0.5. The research focuses on behavior after 28days(after loading). Four-point bending tests are used to pre-cracked the prismatic specimens at 28days. For specimens (uncracked and cracked) submerged in tap-water and sea-water until 60days. According to the experimental results, the TBC paste system has self-healing ability increased when the fraction of GGBFS increased. Because GGBFS and FA continues to hydrate after 28days, it is likely that hydrated products from GGBFS and FA may modify microstructures, seal these cracks. From these results, it is clear that the crack in all samples experience self-healing and that this occurs mostly in the first 30days of submerging. Futhermore, most of the healing for both specimens of submerged in sea-water and tap-water occurred during the first 30days. Sea-water submerged specimens healed cracks as fast as those in tap-water. Differences in healing effects of submerged in sea-water and tap-water may be attributed to the presence of specific sea-water ions. Therefore, self-healing effects considered age-effects was more strong effect occurred mostly in the first 30days, and then gradually weaken.

• Journal of Korean Academy of Nursing
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• v.39 no.3
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• pp.338-348
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• 2009

Purpose: The purpose of this study was to explore and describe healing effects of the forest on alcoholics through a forest experience program. Methods: The qualitative data was gathered from one focus group discussion with 6 alcoholics and individual interviews with 8 alcoholics. They had all participated in a "healing forest" program. All interviews were recorded and transcribed according to thematic content analysis processes. Results: The four main themes on the attributes of forest were "a lively living being", "placidity and tranquility", "acceptive atmosphere", and "beautifulness as it is" which revealed the participants' perceived nature of the forest which was attributed to the healing effects. Eight other themes on participants' positive changes included "revived senses", "aspired to live", "relieved and relaxed from being tense", "gaining insight on self", "having an acceptive attitude", "becoming compliant with his/her life", "learning that life is being together" and "recognizing the value of one's existence". Conclusion: The findings of the study illustrated the participants' self-healing processes through interactions with the nature of the forest. Nursing interventions utilizing healing atmospheres such as "healing forest" programs can be considered helpful in providing a venue to alcoholics to reflect on their lives affirmatively.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.3
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• pp.53-59
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• 2018

When manufacturing self-healing concrete using bacteria, nutrients are added to increase the activity of the bacteria. Although many researches have focused on the effects of nutrients containing bacterial healing agent on concrete, few have studied the effects of sole nutrient on self-healing of cement composites. Bacterial nutrients, like commercial chemical admixtures, affect hydration characteristics such as flow, setting, hydration heat, mechanical strength of cement composites and also affect the self healing of cement composites by hydration of unhydrated particles. In this study, effect of the four nutrient commonly used in the existing literature on the hydration characteristics of cement composites by its addition was investigated. Flow, setting time, hydration heat, compressive strength have studied for each nutrients added by 1.5% and 3% of cement weight. Experimental results shows that urea and calcium-nitrate can be used up to 3% without significant detrimental effect on cement composites. Addition of calcium-lactate up to 1.5% show better compressive strength than control, but addition of 3% show almost non-hydration. Yeast extract shows detrimental effects on the composites regardless of the amount added.

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.11-21
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• 2017

The paper presents experimental results of self-healing effects of OPC-GGBFS paste with cracked and uncracked specimens. The self-healing of cracked specimens is processes of crack closing with re-hydration of unhydrated in crack surface. The OPC paste with GGBFS replacement ratios of 0%, 10%, 20% and 30% were prepared having a constant water-binder ratios of 0.5. The OPC-GGBFS paste specimens immersed in tap-water and sea-water. The temperature of tap and sea-water was $5^{\circ}C$, $15^{\circ}C$ and $25^{\circ}C$. The cracked specimens after deterioration were immersed for 60 days. The relationship between self-healing effect and age-effect was calculate based upon the experimental results. The self-healing effect was measured in ultrasonic pulse velocity (UPV) before and after loading. When the relative change rate of UPV is increases with the increase in GGBFS replacement ratios. Moreover, the self-healing effect is increased with the temperature of tap-water is increase. But the cracked specimens immersed in sea-water was unclear effects of different temperature. Furemore, most of the healing for OPC-GGBFS specimens immersed in tap-water and sea-water occurred during the first 30 days. The self-healing effect until 30 days is higher than that the age-effect. After 30 days, self-effect and age-effect was largely decreases. SEM/EDS analysis of crack on the surface of the specimens in tap-water were covered with aragonite, and sea-water were covered with brucite.

• Journal of Korean Academy of Rural Health Nursing
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• v.15 no.1
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• pp.16-29
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• 2020

Purpose: The purpose of this study was to determine the effect on depression and self-esteem in elders taking part in the Magma healing program. Methods: This study was a single group pre-post quasi-experimental design. The participants were elders over 60 who had complained of depression more than once within the last 3 months, and who were living in the jurisdiction of a health clinic in the 3-area of Chungnam. Data from 14 elders who participated in the Magma healing program were analyzed using nonparametric paired t-test with SPSS 25.0. Results: The study results showed that the Magma healing program had statistically significant results in reducing depression (z=-2.91, p=.004) and improving self-esteem (z=-2.91, p=.004) in elders. Conclusion: The Magma healing program has been proven to be a very useful program to reduce depression in elders and promote self-esteem, thereby integrating their lives and leading to successful aging.

• Journal of Agricultural Extension & Community Development
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• v.30 no.4
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• pp.171-186
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• 2023

This study aims to explore comprehensively the effects of a flower craft activity program focused on perceived stress, depression, and self-esteem of adult with mixed methods. The main results of this study are as follows. In the mixed analysis results, perceived stress was reduced by immersing oneself in completing one's own work through flower craft activities, as distracting thoughts in the head disappeared. In the case of depression, depression decreased in the relationship between group members who worked together to complete their own work through flower craft activities. In the case of self-esteem, it was analyzed that flower craft activities had the effect of increasing self-esteem through the satisfaction of the need for life and self-esteem. In future study, this suggests that the healing program applied based on this can be comprehensively reviewed, modified, and supplemented to reorganize it into a more effective flower craft activity program.

• Korean Journal of Environment and Ecology
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• v.31 no.6
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• pp.595-605
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• 2017

This study was intended to investigate the effects of after-school forest healing programs on the pro-social behavior and self-efficacy of young children using the attributes of forest and the forest healing factors. The children attending a kindergarten located in ${\bigcirc}{\bigcirc}$ - dong, Cheongju city were divided into a test group which participated in the forest healing program activities and a control group which participated in the regular programs of the kindergarten but not in the forest healing program. Each group consisted of 20 boys and girls aged 3 to 5 years. The forest healing program was conducted once a week from 10 April to 10 July in 2017 for a total of 12 sessions, and each session lasted one hour (60 minutes). The pro-sociality behavior and self-efficacy test of the children was conducted before and after the forest healing program, and the data were analyzed using SPSS 18.0 program. The result showed that the pro-social behaviors that indicated the ability to execute the positive action and the self-efficacy that indicated the self-confidence were statistically significant (p<0.05). The young children who participated in the forest healing program improved their self-esteem through positive thoughts from being with their peer in nature. Moreover, they increased not only ecological knowledge but also consideration for others and cooperative spirit. They also greatly improved the ability to control personal emotion and the ability to form the personal relationship which are the sub-factors of pro-sociality, the ability to adapt to the early childhood education institution, and the physical efficacy which is the sub-factor of self-efficacy. It was concluded that the after-school forest healing program had a positive impact on pro-social behavior and self-efficacy.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.236-244
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• 2018

In this study, we tried to fabricate self - healing microcapsules using liquid inorganic materials which can be mixed directly with cement composites. The basic properties of the liquid inorganic material were evaluated and microencapsulation was performed. The focus of this paper is on the quality and manufacturing characteristics of cement composites rather than the healing effects of self - healing microcapsules according to mixed capsules. Test results, the self-healing microcapsules encapsulate liquid inorganic material which is stable at room temperature and has high crack followability, and the yield is over 90%. The size of self - healing microcapsule was able to change according to the synthetic agitation speed and it was able to secure more than 70% of target size. In addition, the loss of less than 10% was found to occur through the membrane strengthening of self - healing microcapsules, and it could be reduced by 50% compared with the case without membrane strengthening.