• Design & Manufacturing
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• v.13 no.3
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• pp.35-40
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• 2019

As the consumer market in the cosmetic, vehicle manufacturing and aerospace industries grows, the demand for manufacturing industries using on injection mold technology. Also, such manufacturing technology of metal machining is expensive, and the shape is limited. Cosmetic cushion fact products are divided into outer relevant to the exterior of the product and inner containers containing the actual contents. In the case of the inner container, it needs to be combined with the upper and lower cases. As environmental regulations are strengthened internationally, the use of a large number of component parts can result in significant losses in recycling and economics. Therefore, this study aims to perform injection molding analysis through injection molding simulation to develop a cushion fact container that can be recycled through the unification of products and materials using polypropylene to cope with environmental regulations. In the case of injection molding conditions, Injection Time(sec): 4.5, Cooling Time(sec): 13, Resin Temperature($^{\circ}C$): 240, and Pressure(MPa): 30 were determined. The results of injection molding simulation according to the two design methods were compared with the sync mark which shows the problem of filling and injection molding.

• Journal of Adhesion and Interface
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• v.22 no.3
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• pp.106-110
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• 2021

Recently, research using waste among eco-friendly materials has been attracting attention. In this study, we investigated the physical properties of blends in which high density polyethylene (HDPE) was filled with waste gypsum (CaSO₄) generated during fertilizer manufacturing. Composites were prepared by adding the gypsum content 0~20 wt% using a twin screw extruder. The mechanical, rheological, and thermal properties of the composites were evaluated. It was found that the tensile strength of the composites was less than 4.1% compared to that of unfilled HDPE, so there is no significant deterioration in physical properties. The thermal stability of the composites was improved as the gypsum content increased and the gypsum content had little effect on the viscosities of the composites.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.3
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• pp.97-105
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• 2021

Most of the rural development projects for the welfare of residents are mainly new construction and remodeling projects for community buildings such as village halls and senior citizens. However, in the case of the construction industry, it has been studied that 23% of the total carbon dioxide emissions generated in Korea are generated in the building-related sector. (GGIC, 2015) In order to reduce the emission of environmental pollutants resulting from construction of rural community buildings, there is a need to establish a system for rural buildings by predicting the environmental impact. As a result of this study, the emissions of air pollutants from buildings in rural communities were analyzed by dividing into seven stages: material production, construction, operation, maintenance, demolition, recycling, and transportation activities related to disposal. As a result, 12 kg of carbon dioxide (CO), 0.06 kg of carbon monoxide (CO), 0.02 kg of methane (CH), 0.04 kg of nitrogen oxides (NO), 0.02 kg of sulfurous acid gas (SO), and non-methane volatile organics per 1m of buildings in rural communities It was analyzed that 0.02 kg of compound (NMVOC) and 0.00011 kg of nitrous oxide (NO) were released. This study proved that environmentally friendly design is possible with a quantitative methodology for the comparison of operating energy and air pollutant emissions through the design specification change based on the statement of the rural community building. It is considered that it can function as basic data for further research by collecting major structural changes and materials of rural community buildings.

• Korean Journal of Materials Research
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• v.29 no.11
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• pp.703-708
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• 2019

In this study, we investigate the relationship between the peeling behavior of the backsheet of a photovoltaic(PV) module and its surface temperature in order facilitate removal of the backsheet from the PV module. At low temperatures, the backsheet does not peel off whereas, at high temperatures, part of the backsheet remains on the surface of the PV module after the peeling process. The backsheet material remaining on the surface of the PV module is confirmed by X-ray diffraction(XRD) analysis to be poly-ethylene(PE). Differential scanning calorimetry(DSC) is also performed to investigate the interfacial characteristics of the layers of the PV module. In particular, DSC provides the melting temperature($T_m$) of laminated ethylene vinyl acetate(EVA) and of the backsheet on the PV module. It is found that the backsheet does not peel off below the $T_m$ of ethylene of EVA, while the PE layer of the backsheet remains on the surface of the PV module above the $T_m$ of the PE. Thus, the backsheet is best removed at a temperature between the $T_m$ of ethylene and that of PE layer.

• Journal of Powder Materials
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• v.28 no.6
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• pp.497-501
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• 2021

Cobalt (Co) is mainly used to prepare cathode materials for lithium-ion batteries (LIBs) and binder metals for WC-Co hard metals. Developing an effective method for recovering Co from WC-Co waste sludge is of immense significance. In this study, Co is extracted from waste cemented carbide soft scrap via mechanochemical milling. The leaching ratio of Co reaches approximately 93%, and the leached solution, from which impurities except nickel are removed by pH titration, exhibits a purity of approximately 97%. The titrated aqueous Co salts are precipitated using oxalic acid and hydroxide precipitation, and the effects of the precipitating agent (oxalic acid and hydroxide) on the cobalt microstructure are investigated. It is confirmed that the type of Co compound and the crystal growth direction change according to the precipitation method, both of which affect the microstructure of the cobalt powders. This novel mechanochemical process is of significant importance for the recovery of Co from waste WC-Co hard metal. The recycled Co can be applied as a cemented carbide binder or a cathode material for lithium secondary batteries.

• Journal of the Korean Society of Food Culture
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• v.25 no.6
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• pp.708-718
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• 2010

This study was conducted to examine the effects of a healthy dietary life and purchase of environmental-friendly food materials according to a mother's lifestyles of health and sustainability (LOHAS) attitudes. The subjects consisted of 295 mothers. The findings are summarized as follows. The mother's LOHAS attitude index averaged 3.39 points out of 5 points. High LOHAS attitude items were "I participate actively in separating the trash collection" (4.16 points), and "I recycle dresses that I do not wear by taking them to the recycling center" (4.08 points). In contrast, LOHAS attitude items for "I do community service activity on the weekend" (2.57 points), and "I try to serve in the local community" (2.63 points) scored very low. A high LOHAS behavior index occurred for mothers who were "resource saving", whereas "social welfare" scored low. Mother's intention to purchase environmental-friendly food materials averaged 3.61 points. Mother's health dietary life attitude score averaged 3.52 points. When age, monthly income, and the environmental-friendly food materials purchase ratio of the mother was high, the health dietary life performance was high. The LOHAS attitude index of mothers had an impact on the purchase intention of environmental-friendly food materials in resource saving and environmental-friendly oriented propensity groups. The LOHAS attitude index of mothers impacted healthy dietary life in environmental-friendly, family and health oriented propensity groups.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.407-415
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• 2008

Hydration reaction of Free-CaO is thought to be the main reason of expansion failure of slag. A lot of research institutions are conducting studies on solutions to this problem, and moreover it has been carried out how to make use of aggregates for concrete. While studies covering wide rage of blast furnace slag have been accomplished in the country, studies on steelmaking slag are insufficient. Therefore, this study aimed at analyzing basic physical properties of electric arc furnace oxidizing slag, which is the main material, and furthermore it focused on how to make use of aggregates for concrete examining chemical mechanism, which can be put to practical use. To address this issue, components of electric arc furnace oxidizing slag were analyzed with measurement of physical properties, followed by long-term strength and detailed durability analysis, which can evaluate the appropriateness of application of cement concrete. Besides the environmental conservation and recycling which can be obtained by application of industry byproducts, commercializing of electric arc furnace oxidizing slag as fine aggregates for cement concrete are expected.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.35-39
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• 2023

ESG (Environment, Social, Governance) has become a major guideline for many companies to improve corporate value and enable sustainable management. Among them, the environment requires a technological approach. This is because technological solutions are needed to reduce or prevent environmental pollution and save energy. Semiconductor package technology has been developed to better satisfy the essential roles of semiconductor packaging: chip protection, electrical/mechanical connection, and heat dissipation. Accordingly, technologies have been developed to improve heat dissipation effect, improve electrical/mechanical properties, improve chip protection reliability, stacking and miniaturization, and reduce costs. Among them, heat dissipation technology increases thermal efficiency and reduces energy consumption for cooling. Also, technology to improve electrical characteristics has had an impact on the environment by reducing energy consumption. Technologies that recycling or reducing material consumption reduce environmental pollution. And technologies that replace environmentally harmful substances contribute to environmental improvement, in particular. In this paper, I summarize trends in semiconductor package technologies to prevent pollution and improve environment.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.575-585
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• 2013

This research was performed to evaluate the recycling feasibility as a construction material of dredged harbor soil mixed with clay and glass frit. Concentration of heavy metals of the dredged soil from D harbor was severly high, showing Zn of 526.0~13,150.1 mg/kg. The dredged soil was maily composed of 48.30 wt% $SiO_2$, 16.60 wt% $Al_2O_3$, 10.10 wt% CaO, 7.75 wt% $Fe_2O_3$. The clay and the glass frit contained 70.82 wt% $SiO_2$ and $Al_2O_3$ 18.78 wt%, and 71.75 wt% $SiO_2$, 13.99 wt% CaO, 8.51 wt% $Na_2O$, respectively. After adding 10~40 wt% to the clay and sintering them at $1,000^{\circ}C$ or $1,100^{\circ}C$, the compressive strength of the sintered specimens showed $132.6{\sim}178.5kgf/cm^2$ or $581.2{\sim}793.7kgf/cm^2$, respectively. In case of SC46 with the addition 40 wt% of the dredged soil to the clay, the compressive strength ($793.7kgf/cm^2$) of specimen sintered at $1,100^{\circ}C$ was over 5 times higher than that at $1,000^{\circ}C$. The specimen mixed with 40 wt% of dredged soil, 60 wt% of clay and 1 wt% of glass frit satisfied the 1st grade standard for clay brick by KS L 4201. The results of all specimens by Korean Standard Leaching Test also satisfied the standard criteria.

• Resources Recycling
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• v.23 no.2
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• pp.17-25
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• 2014

The thermal effect on the compositional change of the $SO_2$ absorption process product was investigated compared with the composition of raw material when dolomite is employed in place of lime in the scrubbing process based on thermodynamic estimation. It was considered that the equilibrium reactions which directly related with the formation of $CaSO_4$ and $MgSO_4$, the absorption process products, are those between $Ca^{2+}$ and $Ca(OH)_2$, $Mg^{2+}$ and $Mg(OH)_2$, and the secondary dissociation reaction of $H_2SO_4$. It was thought to be necessary to examine the enthalpy change for the formation reactions of $CaSO_4$ and $MgSO_4$ along with the thermal feature of the relative reactions to figure out the influence of temperature on the compositional change of absorption process products. The stable regions for $Ca(OH)_2$ and $Mg(OH)_2$ in Pourbaix diagram were found to be increased as temperature rises and the equilibrium reaction between $Ca^{2+}$ and $Ca(OH)_2$ was investigated to be more strongly influence by temperature change compared with the equilibrium reaction between $Mg^{2+}$ and $Mg(OH)_2$. The amounts of $CaSO_4$ and $MgSO_4$ were anticipated to be decreased with temperature considering the thermal characteristics for the equilibrium reactions regarding calcium, magnesium, and $H_2SO_4$. It was understood that the formation ratio between $CaSO_4$ and $MgSO_4$ is greater than the composition ratio between calcium and magnesium contained in dolomite at specific temperature and the decrease of the formation ratio of $CaSO_4$ and $MgSO_4$ with temperature was estimated to be diminished as the content of calcium in dolomite is increased. In addition, the extent of the change in the compositional ratio between absorption process products was examined to be reduced compared with the composition of raw material as the calcium content in dolomite is raised.