• Geomechanics and Engineering
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• v.12 no.5
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• pp.831-847
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• 2017

Conventional geotechnical engineering soil binders such as ordinary cement or lime have environmental issues in terms of sustainable development. Thus, environmentally friendly materials have attracted considerable interest in modern geotechnical engineering. Microbial biopolymers are being actively developed in order to improve geotechnical engineering properties such as aggregate stability, strength, and hydraulic conductivity of various soil types. This study evaluates the geotechnical engineering shear behavior of sand treated with xanthan gum biopolymer through laboratory direct shear testing. Xanthan gum-sand mixtures with various xanthan gum content (percent to the mass of sand) and gel phases (initial, dried, and re-submerged) were considered. Xanthan gum content of 1.0% sufficiently improves the inter-particle cohesion of cohesionless sands 3.8 times and more (up to 14 times for dried state) than in the untreated (natural) condition, regardless of the xanthan gum gel condition. In general, the strength of xanthan gum-treated sand shows dependency with the rheology and phase of xanthan gum gels in inter-granular pores, which decreases in order as dried (biofilm state), initial (uniform hydrogel), and re-submerged (swollen hydrogel after drying) states. As xanthan gum hydrogels are pseudo-plastic, both inter-particle friction angle and cohesion of xanthan gum-treated sand decrease with water adsorbed swelling at large strain levels. However, for 2% xanthan gum-treated sands, the re-submerged state shows a higher strength than the initial state due to the gradual and non-uniform swelling behavior of highly concentrated biofilms.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.2
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• pp.117-124
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• 2015

Currently, Eco-friendly construction materials are widely utilized for reducing $CO_2$ emission in construction. Furthermore various engineering fibers are also added for improving a brittle behavior in concrete. In the paper, concrete specimens with 10% and 20% replacement ratio with RHA (Rice Husk Ash) are prepared, and engineering behaviors in RHA and OPC concrete are evaluated with different addition of coconut fiber from 0.125~0.375% of volume ratio. Several basic tests including compressive strength, tensile strength, flexural strength, impact resistance, and bond strength are performed, and crack width and deflections are also measured in flexural test. RHA is evaluated to be very effective in strength development and 0.125% of fiber addition leads significant improvement in tensile strength, ductility, and crack resistance. RHA and coconut fiber are effective construction material both for reutilization of limited resources and performance improvement in normal concrete.

• Journal of the Korea Convergence Society
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• v.8 no.2
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• pp.113-120
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• 2017

The purpose of this present study was to evaluate the surface radiation dose reduction and radiograph artifact images in computed tomography (CT) for the manufactured radiation shields by using sea-shells. The radiation convergence shields were made from silicons, sea-shells, barium powders, producted circle types of diameter 50 mm, thickness 3.5 mm for 5 kinds (only silicon shield, only barium shield, mixed sea-shells with silicon shield, mixed barium with silicon shield, mixed sea-shells with barium and silicon shield). Radiation generation and acquisition were used 4-channel multi-detector CT. The results of this study showed that mixed sea-shells with silicon shields could reduce the surface dose of 5.3% without radiograph artifact images. In the future, we will expect the radiation convergence shield as environmentally friendly materials by using the recycling of sea-shells with the advantages of silicon which can make various shapes.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.4
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• pp.43-56
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• 2014

In this study, ecological investigation was performed on Yong-neup, Daeam-san for 5 times. This area is considered DMZ zone located between Yanggu-gun and Inje-gun, Gangwon-do, where has been recognized highly valuable for ecological preservation. As a result, Sphagnum and hydrophobic vegetation were found in Little Yong-neup, revealing its characteristics of high moor, where as no Sphagnum were found in Baby Yong-neup. Thereby, the carnification has been investigated in both Little Yong-neup and Baby Yong-neup. A main cause of damage was associated with the creation of stating rink and increases of visitors. The damages of vegetation in Little Yong-neup and Baby Yong-neup have been intensified by road construction or uses of groundwater while relocating military troops to upper stream of Little Yong-neup and Baby Yong-neup, further causing the damages of water circulation system and soil erosion. These artificial factors have caused the carnification of wetland protection areas including Little Yong-neup. The terrestrial vegetations, such as Plantago asiatica, Geranium Koreanum and Artemisia feddei have increased compared to current survey conducted by the Ministry of Environment. 5 endangered species, such as Lychnis wilfordii and Trientalis europaea and 5 other introduced species, such as Aster pilosus and Taraxacum officinale were found. 10 different species of mammal and 2 species of amphibian were investigated; and in addition to this, a original form of Sphagnum fens, the remaining wetland was found. Therefore, this study is to identify the causes of damages in Little Yong-neup and Baby Yong-neup through their ecological survey and accordingly proposing a direction for ecological restoration through the improvement of water circulation system, creation of habitats for plant and animal, restoration of vegetation through eco-friendly materials and indigeneity, relocation of the current military troops, securing of structural stability.

• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.54-61
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• 2001

As a part of the movement of natural resources conservation, there have been doing many recycling research works for obsolete aged tire, wasted plastic materials, etc. The purpose of this experimental study is to develop glass concrete by recycling wasted glasses as a cementitious constituent in concrete. First of all, the optimum replacement ratio of powdered waste glasses(PWG) can be determined through pilot compressive strength test on normal and high strength concrete cylinders, which have been made in various mix proportions by changing the replacement ratio of PWG. Then, further tests have been done to figure out mechanical properties of most desirable glass concrete with optimum replacement ratio of PWG, such as static modulus of elasticity, compressive and tensile strengths, flexural strength. On the other hand, the alkali-silica reactions by the mortar-bar method(KS F 2546) have been experimentally doing in various grain sizes of PWG, since the alkali in the cement has a tendency to react with the silica in the PWG. In can be confirmed from the test that glass concrete can have better workability than concrete with silica fume, and they are alike in compressive strength. It is concluded that wasted glasses can be used as pratical additives for economic and environmentally friendly concrete.

• Journal of the Korean GEO-environmental Society
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• v.3 no.3
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• pp.27-36
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• 2002

Generally, it is known that urethane injection is excellent in long-term durability and environment friendly for ground improvement. However, urethane grouting has short rise time thus the penetration distance from the injection point is so short. Therefore, urethane injection cannot be used for the site where requires ground improvement in deep location from the injection point. Other injection materials such as cement cannot be alternatives when rapid hardening is required. From this study, we improve disadvantage urethane injection by developing TAS method. From the field tests, it is ascertained that TAS increases injection distance over 10m, which is further than that of original urethane grouting. In addition, TAS has relatively short Rise-time compared to cement grouting thus instantaneous improvement can be mobilized right after the injection. Short Rise-time and long penetration distance provide excellent applicability for tunnel construction.

• Journal of the Korean GEO-environmental Society
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• v.10 no.4
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• pp.25-31
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• 2009

In this study, the problem of existing soil pavement is a long-term durability lack and crack occurrence. It complements in order to develop the environmental soil pavement material which composites readily blended mineral binder of liquid and decomposed granite soils. It was estimated optimal mixture proportion for unconfined compressive strength, permeability, $Cr^{6+}$detection test, SEM test with age, freezing and thawing test. It resulted mixture proportion of powder types mineral binder for rates of cement : fly ash : plaster was optimal rates of 50 : 33 : 7, and $Cr^{6+}$detection test as a result was a slight production. SEM test with 3days as a result was made Ettringite. It was found that this material was early development of early-strength for chemical. This study indicated that it will execute field appliciability Evaluation test, examination of soil pavement method with decomposed granite soils and mineral binder.

• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.45-55
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• 2015

In Incheon area, 1960s of economic development planning and heavy industry center of efforts industrial park and port facilities, It is industrial land reclamation by coastal landfill, these industrial park has the characteristics of Low permeability lipid is embedded in the silty sand that was dredged. In this study, To evaluate the heavy metal adsorption ability to filter of drains that have been developed as environmentally friendly materials by applying the effective zeolite to heavy metal adsorption for soil pollution purification suitable for geological characteristics of Incheon. soil pollution Survey data and Literature search, which is the current through the industry, the most problematic was set to Cadmium (Cd) and Copper(Cu), Lead (Pb). and Using the Numerical Analysis using the Visual Modflow, was presented the most efficient drains set interval and format.

• Journal of the Korea Fashion and Costume Design Association
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• v.19 no.2
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• pp.49-61
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• 2017

The purpose of this study was to develop an educational program designed to allow students to experience 'up-cycling' first-hand during class and understand its significance by helping them improving their practical problem-solving abilities. Teachers of home economics, Korean, and social studies to third grade middle schooler were asked to analyze the curriculums of their subjects. The analysis results were then used to identify common elements among the units, reconstruct the curriculums, and develop an integrated lesson program to offer integrated activities. Based on these, a lesson program was developed to make an eco-bag and running shoes under the theme of 'up-cycling' in the unit of 'environmentally-friendly clothing and mending of clothes' in the home economics subject. The results were as follows: First, a topical fusion lesson program was developed to integrate three subjects together. The development process involved the integration of the topic of up-cycling, a program model for integrated lessons, and a teaching and learning process plan for topical integrated education. Secondly, a lesson program for home economics was developed that was applicable to actual home economics lessons based on the topical integrated lesson program. The lesson domains were divided into large, medium, and small to create a ten-lesson teaching and learning process plan needed for the lessons, teaching materials that could be put to actual uses in lessons, and activity and evaluation logs for learners.

• Korean Journal of Construction Engineering and Management
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• v.5 no.6 s.22
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• pp.154-161
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• 2004

The term 'well-being' which becomes a popular trend in various industries has been introduced in the housing market as well. This trend could be understood as an emerging trend rooted to customers' preference for apartment enabling residents to live comfortably and healthy in 2000s. The housing industry has attempted to meet customers' requirements by presenting' well-being apartments' emphasizing healthy and natural-friendly aspects. For instance, suppliers in the industry has adopted master plans and unit plans to support well-being residence. In addition, they introduced less-toxic-emission materials to interior However, it has been unknown that customers in the housing market also agree to well-being functions presented by suppliers and, if then, which aspects they consider mon important In order to answer questions stated above, a research to investigate perceptions of potential customers in Busan towards well-being apartments is designed and this paper is a summarized result. Based on the real-world investigations, the important functions or concepts relevant to well-being apartments perceived by customers are defined and suppliers' approach to meet these Is presented.