• Journal of the Korean Ceramic Society
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• v.45 no.8
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• pp.443-452
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• 2008

Shrinkage crack is a major concern for cement materials, especially for flat structures such as Korean On-Dol floor system, flooring for garages, and wall. One of the methods to reduce the adverse effects of shrinkage cracking is to reinforce cement materials with shot randomly distributed fibers. The efficiency of inorganic fibrous material to arresting cracks in cementitious composites was studied. Cement materials reinforced with five different qualities of inorganic fibrous material were tested. Contents of inorganic fibrous material were 1.0 kg, 1.5 kg, 2.0 kg, 2.5 kg, 3.0 kg by weight of cement mortar and C : S types of cement mortar were 1:3 and 1:4. W/C were 60% and 80%. Cement mortar of inorganic fibrous material reinforcement showed an ability to reduce the crack width and crack length significantly as compared to unreinforced cement mortar. $40%{\sim}60%$ drop in shrinkage crack of 1:4 cement mortar with 1.5 kg over was observed.

• Advances in materials Research
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• v.4 no.3
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• pp.165-178
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• 2015

Friction coefficient of epoxy metal matrix composites were investigated. The main objective was to increase the friction coefficient through rubber sole sliding against the epoxy floor coating providing appropriate level of resistance. This was to avoid the excessive movement and slip accidents. Epoxy metal matrix composites were reinforced by different copper wire diameters. The epoxy metal matrix composites were experimentally conducted at different conditions namely dry, water and detergent wetted sliding, were the friction coefficient increased as the number of wires increased. When the wires were closer to the sliding surface, the friction coefficient was found to increase. The friction coefficient was found to increase with the increase of the copper wire diameter in epoxy metal matrix composites. This behavior was attributed to the fact that as the diameter and the number of wires increased, the intensity of the electric field, generated from electric static charge increased causing an adhesion increase between the two sliding surfaces. At water wetted sliding conditions, the effect of changing number of wires on friction coefficient was less than the effect of wire diameter. The presence of water and detergent on the sliding surfaces decreased friction coefficient compared to the dry sliding. When the surfaces were detergent wetted, the friction coefficient values were found to be lower than that observed when sliding in water or dry condition.

• Journal of the Korea Concrete Institute
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• v.15 no.4
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• pp.549-556
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• 2003

Various researches on the application of polymer dispersions to the cement mortar and concrete have been practised in many countries like America, Japan and Germany and so on because of high performance and good modification effect of these. In this study, SBR, Polymer dispersion that widely used in situ is employed that the self-flowability may be induced in the cemen mortar. In order to comprehend and investigate the modification of cement mortar with self-flowability by SBR and properties and fracture mode of adhesive strength in tension of that, experimental parameter was set as SBR solid-Cement ratio(S/C) and Cement:Fine aggregate(C:F) and the experiments such as Unit weight, Flow, Consistency change, Crack resistance and Segregation that inform on the general properties have been done. In addition of that, Adhesion in tension is measured with a view to comprehending the properties and fracture mode in tensile load. Consistency change of cement mortar modified by SBR did grow better as the ratio of SBR solid-Cement increased and was much superior to that of resin based flooring such as polyurethane and epoxy which recorded the loss of consistency in 90min. after mixing. Adhesive strength in tension increased with continuity in the curing age and showed the maximum in case of C:F=1:1 and S/C=20%. As the increase of curing age, the fracture mainly happened in the concrete substrate and the interface between the specimen and concrete substrate.

• Korean Institute of Interior Design Journal
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• v.25 no.5
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• pp.121-129
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• 2016

With the ingenious properties of unconstrained formativeness and frank expression of materiality the exposed concrete became popular with numerous architectures. The application of the exposed concrete has expanded to indoor environments such as commercial and residential spaces beyond the building exteriors with the uncompromising nature of its materiality. The purpose of this study is to conduct sensibility evaluation of the exposed concrete finish in interior spaces. The sensibility evaluation is conducted through a survey on a set of space models of the exposed concrete finish. The three rendered space models were evaluated by emotional vocabulary of 18 pairs of words. The result were as follows: First, the emotions derived from the exposed concrete finish are 'modern', 'cold', 'simple', 'restrained', 'rough', 'dark', 'new', 'chic', 'familiar' and 'eco-friendly'. Second, three sets of space models with alternative materials on walls and floors in exposed concrete interior space showed clear difference in sensibility. A space with the exposed concrete finish on the floor, the walls and the ceiling showed the results of 'cold', 'dark', 'rational' and 'masculine'. In the exposed concrete finish environment with wood flooring 'comfortable', 'warm', 'bright' senses and with white paint finish on the wall 'bright', 'practical', 'ordinary' and 'restrained' senses were obtained. Third, all three images achieved senses of 'chic', 'modern', 'new', 'pleasant', 'environment friendly' and 'satisfactory'. The modernity and stylish expressions of the exposed concrete finish were kept with the application of different material finishes as well as complementing its cold and rough expressions with warmth and brightness.

• Journal of Animal Environmental Science
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• v.5 no.1
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• pp.1-15
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• 1999

The structural and environmental characteristics of typical pig houses in different growth phases were surveyed and analyzed. Based on the data for thirty six selected farms in four provinces, Gyonggi-do, Gangwon-do, Choongnam, and Chonbook, in Central Korea, the goal is to eventually establish standard pig houses of sow and litter, nursery pigs, and growing-finishing pigs. The survey included farm scale, production specialization, structural dimensions of the houses and their ventilation systems, cooling and heating systems, and floor and pit systems related to manure collection. The survey showed 90∼99% of growing-finishing curtain installation rate was lower by 10∼20%. The sidewall curtain system, although popular, is not well insulated which leads to excessive heating costs in winter. Regarding flooring and manure collection system of the house, there was quite a lot variability among provinces, with 30∼80% of the houses installing scraper systems with concrete-slat floors in comparison with 30∼60% using a slurry system. Gangwon-do and Choongbook Chungwoo-goon are the predominant regions that installed a scraper system. A general trend toward enlargement and enclosure of pig houses for all growth phases was gaining popularity in most regions in recent years. A steady shift to three site production from a lumped system was also observed to prevent a disease transfer. The structural design of a standard pig house with its environmental control systems including ventilation and heating/cooling system was suggested for further validation study. In-depth analysis of the survey data is presented in the Results and Discussing section.

• Journal of Environmental Science International
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• v.27 no.2
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• pp.123-133
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• 2018

The historical exchanges between the Republic of Korea and Japan have broadly occurred, in terms of both political and cultural aspects, from ancient to modern times. Regarding ancient gardening culture, in particular, Asuka developed gardens with the gardening techniques passed down by the Baekje people. The development of the basic form of a garden pond along with its characteristics, established through such exchanges, is suggested by investigating its components through analysis of data from the gardens of Baekje and Asuka. In terms of the garden pond structure, homogeneity was confirmed between Baekje and Asuka, with a linear rectangular form as the basic design. In addition, the vertical construction technique was used by both ancient kingdoms. In terms of the types of stone used in building the shore of the garden pond, Baekje used diverse types such as natural stone, crushed stone, and cut stone. In contrast, rounded river stone was used by Asuka. Regarding the floor of the garden pond, Baekje used soil, which enabled the planting of lotus flowers. In contrast, Asuka used stones to pave pond floors, which made the growth of plants impossible. In terms of layout, Baekje used ornamental stones for pond landscaping, while Asuka used manmade island and water intake facilities in their pond construction. The effects of Baekje's garden culture on Asuka's garden building can be seen from its influence on the form of the garden pond and shore construction style. In terms of the construction of the garden pond's shore with the same stones and the stone flooring, the garden ponds of the Asuka Kingdom reveal technically unified and refined aspects.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.629-634
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• 2016

In this study, we investigated the effect of factors that influence the measurement of smoke density using synthetic rubber flooring. The characteristics of rolling stock in an enclosed environment can cause enormous loss of life by smoke inhalation during fires inside passenger cars. The amount of smoke generation from interior materials for rolling stock is strictly restricted domestically and in other countries. Precise measurement of smoke density is therefore required to assess the fire performance of interior materials. Major factors that influence the measurement of smoke density include the uniformity of the specimen, the variations in conditions and instruments, and the operational and maintenance environment of the instruments. The contribution of factors was analyzed by estimating the uncertainty to investigate the contribution ratios of the major factors. The results show a contribution ratio of about 86% for the variation from the measurement of light transmission using a photomultiplier tube. Thus, this factor was the most representative for the measurement of smoke density. The contribution ratio of the other factors was low at about 11%, including irradiant flux conditions (${\pm}0.5 kW/m^2$) and the influence of the operational and maintenance environment of the instrument. These results were obtained using specimens with high uniformity.