• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.433-439
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• 2023

In this study, the bonding performance of repair materials was evaluated on concrete repair surface to develop concrete repair materials based on UHPC (Ultra High Performance Concrete) which has high mechanical and durability performance. The ten test variables were applied considering the roughness and wet condition of the concrete surface subject to repair, the addition of polymer, and the use PP and PVA fibers in repair materials. The addition of the polymer caused a significant decrease in strength, which was thought to be due to the effect of the additional super plasticizer used to adjust workability. Also, flow was reduced by up to 13.8 % with the use of plastic-based fibers. As a result of evaluating the bond strength of the repair material considering the condition of the surface subject to repair, it was thought that in the case of using UHPC-based repair material, high bonding performance could be secured without any additional surface treatment as long as the surface of the base material was sound. In addition, UHPC-based repair materials showed high bonding performance even when the attachment surface was wet. In the future, research will be conducted on shot-crete application and gradient pouring for the development of UHPC-based repair materials, and continuous improvement in the repair material mixing property will be carried out to ensure economic efficiency and performance as a concrete structural repair material.

• Clean Technology
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• v.18 no.1
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• pp.111-119
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• 2012

These days many companies are trying to reduce, recycle and reuse their wastes. Even though many wastes can be recycled, those are incinerated or landfilled. To solve these problems, there are many projects to make efforts to recycle wastes in especially the industrial complexes. But, due to the absence of information about waste recycling, recyclable wastes are still incinerated or landfilled. Based on these research background, this study aims to suggest the evaluation methodology of the $CO_2$ emissions and cost reduced by circulating the industrial waste to resource. We evaluated the environmental and economic effect between companies which emit the plastic waste and organic solvent waste and use them as raw-materials in the off-line recycling information exchange network. The environmental and economic aspects were analyzed comparing waste recycling with waste incineration. By recycling the plastic waste as raw-materials, $CO_2$ emission were reduced 1,070 ton in 2009 and 1,234 ton in 2010 and 657.4 million won in 2009 and 755.0 million won in 2010 were reduced. In recycling the organic solvent waste, 7.3 ton-$CO_2$ in 2010 and 5.6 ton-$CO_2$ in 2011 were reduced and 15.9 million won in 2010 and 12.2 million won in 2011 were reduced.

• Resources Recycling
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• v.26 no.1
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• pp.69-77
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• 2017

Used small household appliances(small e-waste) consists of a variety of complex materials and components. The small e-waste is mainly composed of plastics and an important potential source of waste plastic. The black plastics, particularly are very difficult to separate by resin type and therefore these are mainly recycled in the form of a mixtures. In the present study, the sorting technologies such as gravity and electro static separation, near-infrared ray(NIR) and IR/Raman optical sorting separation on mixture of black plastics were analyzed and their limitations on sorting process were also investigated. The Laser Induced Breakdown Spectroscopy(LIBS) spectrum of each black plastics was used for identification of black plastics by resin type, and after analyzing the normalization operation, Principal Component Analysis(PCA) was carried out. The spectrum data was optimized through PCA process. In order to improve the identification accuracy and sorting efficiency of black plastics, it is necessary to design a classifier with high efficiency and to improve the performance and reliability of the classifier by applying the field of intelligent algorithms.

• Design Convergence Study
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• v.14 no.4
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• pp.119-132
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• 2015

The enforcement of volume-rate disposal system which has been resulted in reducing the household waste and increasing the amount of recycled contents is showing positive effects that are generating social and economic benefits, However due to the lack of user's perception about how to separate and dispose of recycling wastes, some problems are constantly raised, like food waste is disposed in the standard volume-rate garbage bag. By rearranging visual information printed on standard plastic garbage bags (SPGB), this study attempted to find ways to deliver the information regarding how to use them properly. In order to achieve this, from the perspective of visual information design, the study examined the cases of visual information printed on nine SPGB from domestic and overseas. Among these, this study conducted a survey on user's awareness of visual information printed on SPGB in three districts of Seoul, Korea. As a result, user-preferred items were identified. Based on the result, this study selected information to be printed on SPGB, established the hierarchical order of the selected information, and proposed a guideline for using SPGB with informative graphics; therefore, the effectiveness of information delivery was improved. In addition, this study also examined the external validity of the guideline by comparing a survey on user's awareness.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.515-521
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• 2023

In this study, waste carbon fiber obtained by pyrolysis of carbon fiber reinforced plastic (CFRP) was used to produce carbon fluoride through vapor phase fluorination and recycled as a reducing electrode material for lithium primary batteries. First, the physicochemical properties of the waste carbon fiber obtained by pyrolysis were determined, and the structural and chemical properties of carbon fluoride were analyzed to evaluate the effect of vapor phase fluorination on the waste carbon fiber. XRD analysis confirmed that the hexagonal network carbon laminated structure (002 peak) of the waste carbon fiber was gradually converted into a carbon fluoride structure (CF_X, 001 peak) as the temperature of gas phase fluorination increased. The discharge capacity of the lithium primary battery produced using this carbon fluoride was up to 862 mAh/g. This was compared to the discharge capacity of carbon fluoride-based Li-ion batteries made of other carbon materials. These results suggest that carbon fluoride made from waste CFRP-based carbon fibers can be used as a reducing electrode material for Li-ion batteries.

• Human Ecology Research
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• v.58 no.3
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• pp.279-298
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• 2020

The purpose of this study is to develop home economics educational programs on the theme of 'improving consumer life' for sustainable development. It is a program to enhance the changemaker mindset for responsible production and consumption among the 17 goals of the Sustainable Development Goals(SDGs). The program was developed 8 that to make solar cookers, make household goods from recycled materials, change maker-practice green life, eco-friendly journal 1, plastic warnings, design alternatives for disposable products, change maker-efforts and eco-friendly journal 2. The developed program was validated 3 times by a group of experts and students. This program has the following features. First, the Home Economics Education(HEE) program under the theme of 'Improving consumer life' for sustainable development are carried out at the stage of change-maker education with project-based process. It can improve students' collaboration skills, self-directed skills, communication skills and problem solving skills. Second, eight programs can increase understanding and interest in sustainable development, and learners are interested in social issues. This program can raise learners who play an active role in solving social problems by increasing their interest and interest in the class, free from the form of passive classes. Third, the HEE programs under the theme of 'Improving consumer life' for sustainable development are meaningful in that they are closely related to students' lives and encourage them to practice in their own lives. Fourth, since the program is well-suited to the present time and includes content elements for sustainable development, it can induce changes in learners' perceptions, attitudes and behaviors.

• Journal of Auto-vehicle Safety Association
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• v.8 no.4
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• pp.24-30
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• 2016

In Korea, the Vehicle Dismantler and Recycler industry is supervised by the Ministry of Land, Infrastructure and Transport under the Automobile Management Act. Also, Korean Automotive recycling businesses are supervised by the Minister of Environment under the Resource Recirculation Act. The main concern of the Minister of Environment is how the wastes from Dismantled vehicles will be environmentally removed, stored, treated, recycled or disposed. In 2000, the European Union (EU) adopted the End-of-Life Vehicles Directive (2000/53/EC) which required Members to ensure the collection, treatment and recovery of end-of-life vehicles (ELVs). The Directive, the most tightly regulated and precautionary legal systems, required that the last owner of a vehicle could drop off the ELV at an authorized treatment facility and that the producers of the ELV should pay the cost of the program. The adoption of the ELVs directive has led the development of Automotive Dismantler and Recycler networks to reuse, refurbish, remanufacture, recycle and recover parts and materials embedded in ELVs. Also, the ELVs directive which has had an insignificant impact on Korean manufacturers has strong presence in the European market and has been successfully externalized on them. The Korean manufacturers not only achieve the 85% recycling target set by the ELVs directive but also meet the Extended Producer Responsibility (EPR) which requires manufacturers to contribute dismantling process. In order to improve the Korean vehicle dismantling and recycling system, the Automobile Management Act and the Resource Recirculation Act should be harmonized. Particularly the roles of the Ministry of Land, Infrastructure and Transport and the Minister of Environment should be sharply divided. Like Japan, the ELV management needs to be highly centralized, regulated, and controlled by the ministry specialized in Vehicle, namely the Ministry of Land, Infrastructure and Transport and the sub organizations. Like EU Members, recovery, reuse, and recycling must be distinguished. Recovery is defined as the final productive use of the parts and materials embedded in ELVs, which includes reuse and remanufacture of parts and recycling of the other materials. Dismantling process and reuse and remanufacture of parts must be governed by the Ministry of Land, Infrastructure and Transport. For environmental recycling or disposal of waste materials, such as CFCs, glass and plastic material, and toxic substances, governmental financial support system should be in place.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1551-1561
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• 2012

Boat or yacht hulls are mainly built using FRP composite materials. FRP boat hull manufacturing has been restricted since 2000 under international regulations on ocean environment safety. FRP composite materials cannot be recycled and require more than 100 years to biodegrade. Therefore, alternatives to FRP have been proposed by many boat builders. Steel, aluminum, and FRP are commonly used as boat hull materials. Their design specifications are proposed as Korean register of shipping. However, the design specifications for inexpensive materials for a small boat have not yet been studied. Small shipbuilders manufacture and sell HDPE canoes or HDPE kayaks. In this study, a hull form was designed based on actual boats. The thickness of an HDPE boat hull was determined based on ISO 12215-5 structural design specifications.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.535-543
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• 2019

Building on/with expansive soils with no treatment brings complications. Compacted expansive soils specifically fall short in satisfying the minimum requirements for transport embankment infrastructures, requiring the adoption of hauled virgin mineral aggregates or a sustainable alternative. Use of hauled aggregates comes at a high carbon and economical cost. On average, every 9m high embankment built with quarried/hauled soils cost $12600MJ.m^{-2}$ Embodied Energy (EE). A prospect of using mixed cutting-arising expansive soils with industrial/domestic wastes can reduce the carbon cost and ease the pressure on landfills. The widespread use of recycled materials has been extensively limited due to concerns over their long-term performance, generally low shear strength and stiffness. In this contribution, hydromechanical properties of a waste tyre sand-sized rubber (a mixture of polybutadiene, polyisoprene, elastomers, and styrene-butadiene) and expansive silt is studied, allowing the short- and long-term behaviour of optimum compacted composites to be better established. The inclusion of tyre shred substantially decreased the swelling potential/pressure and modestly lowered the compression index. Silt-Tyre powder replacement lowered the bulk density, allowing construction of lighter reinforced earth structures. The shear strength and stiffness decreased on addition of tyre powder, yet the contribution of matric suction to the shear strength remained constant for tyre shred contents up to 20%. Reinforced soils adopted a ductile post-peak plastic behaviour with enhanced failure strain, offering the opportunity to build more flexible subgrades as recommended for expansive soils. Residual water content and tyre shred content are directly correlated; tyre-reinforced silt showed a greater capacity of water storage (than natural silts) and hence a sustainable solution to waterlogging and surficial flooding particularly in urban settings. Crushed fine tyre shred mixed with expansive silts/sands at 15 to 20 wt% appear to offer the maximum reduction in swelling-shrinking properties at minimum cracking, strength loss and enhanced compressibility expenses.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.30 no.1
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• pp.53-62
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• 2024

Molded pulp products has become more attractive than traditional materials such as expanded polystyrene foam (EPS) owing to low-priced recycled paper, environmental benefits such as biodegradability, and low production cost. In this study, various design factors regarding compression and cushioning characteristics of the molded pulp cushion with truncated pyramid-shaped structural units were analyzed using a test specimen with multiple structural units. The adopted structural factors were the geometric shape, wall thickness, and depth of the structural unit. The relative humidity was set at two levels. We derived the cushion curve model of the target molded pulp cushion using the stress-energy methodology. The coefficient of determination was approximately 0.8, which was lower than that for EPS (0.98). The cushioning performance of the molded pulp cushion was affected more by the structural factors of the structural unit than by the material characteristics. Repeated impacts, higher static stress, and drop height decreased the cushioning performance. Its compression behavior was investigated in four stages: elastic, first buckling, sub-buckling, and densification. It had greater rigidity during initial deformation stages; then, during plastic deformation, the rigidity was greatly reduced. The compression behavior was influenced by structural factors such as the geometric shape and depth of the structural unit and environmental conditions, rather than material properties. The biggest difference in the compression and cushioning characteristics of molded pulp cushion compared to EPS is that it is greatly affected by structural factors, and in addition, strength and resilience are expected to decrease due to humidity and repetitive loads, so future research is needed.