• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.137-138
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• 2003

The worldwide annual production of polyolefins amounted to 60 million tons in 2000. During the process, 1-2 wt% of the olefin monomers have been emitted and flared into the air, causing the huge energy consumption and severe carbon dioxide emission. Recently, membrane process has been proved to be the most competitive among other separation processes in terms of cost of equipments, energy consumption and safety in this application. The performance of membrane process highly depends on the membrane properties and thus, it is very important to develop good membrane materials and composite membranes. We prepared PMDS dense and composite membranes and studied basic permeation behaviors of a series of olefins(ethylene, propylene, 1 -butylene), nitrogen and hydrogen as model gases.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1032-1038
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• 2017

Recently, regulation on carbon emissions has been strengthened according to the new climate change convention (COP21) held in Paris, and then Korea has decided to reduce CO2 emissions by 37% until 2030. As one of countermeasures, the government has energetically performed demonstration projects of island micro-grid including solar power, wind power and energy storage system. However, in order to smoothly introduce island micro-grid, it is a critical issue to carry out the economic evaluation for power utility aspect and independent power producer aspect. Therefore, this paper proposes economic evaluation algorithms of island micro-grid which are based on the present worth method, considering cost and benefit factors in the aspect of both sides. Firstly, in case of power utility this paper proposes algorithm to estimate a period of return on investment according to the introduction capacity of distributed generators replacing diesel generator. And also, in case of independent power producer, this paper proposes evaluation algorithm to estimate weighting factor of SMP and benefit rate based on break-even point related with cost and benefit. From a case study result on real island micro-grid model, it is confirmed that proposed algorithms are useful and practical for the economic evaluation of island micro-grid.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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• pp.668-681
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• 2013

The Korean government announced a national mid-term target to reduce 30% of greenhouse gas (GHG) emissions from business-as usual (BAU) level by 2020 in a voluntary and independent manner. In this study, we examined the $CO_2$ mitigation potential and conducted an economic effect analysis of green living actions in households in Korea. We also proposed some ways to implement green life to achieve the national target. If green lifestyle takes root in households nationwide, $CO_2$ emission would be reduced to 27.3% of the emission in 2007. This would save the country about 4.93 trillion won per year and each household could save about 300,000 won per year, which accounts for about 0.5% of GDP (as of 2007). Considering the five-year plan for green growth to invest 2% of GDP in green growth every year, this would not only reduce the economic burden on households, industries and the country but also increase economic growth potential by reinvesting the saved resources into green growth. Heating and lighting would be the greatest contributor to GHG mitigation of green life in the residential sector. It means we could achieve the national goal by reducing unnecessary heating and lighting and using energy-saving electric home appliances. The implementation of green living actions would reduce a significant amount of greenhouse gas emissions, ultimately relieving the burden on businesses to reduce GHG emissions. And it is one of the most cost-effective mitigation tools in order to achieve the mid-term GHG mitigation goal.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.148-149
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• 2021

Food waste has increasingly become a global issue of concern among the researchers and policymakers due to its significant environmental and economic impacts, and other associated unsustainable use of resources, including water resources. While food wastage occurs at each stage of the supply chain with food loss at the upstream and food waste at the downstream, the impacts of food waste occurring at the consumption side are enormous due to the accumulated added values. In this study, the embedded water resources, greenhouse gas emissions, and economic loss of household food waste were investigated. The primary granular data of household food waste was collected through direct sampling from 218 selected households of the Buk-gu community in Daegu, South Korea from July 2019 to May 2020. The water footprint, which was based on the water footprint concept, i.e., indirect water use, and GHG emission potential factor for each of the food items were adopted from the literature, while the retail prices and disposal cost were used to assess the economic cost of wasted food items. The water footprint, GHG emission associated with environmental impacts, and the economic cost of 42 major identified wasted food items were conducted. The findings showed that an average of 0.73 ± 0.06 kg/household/day edible food waste was generated among the sampled households, with leafy vegetable, watermelon, and rice responsible for 10, 9, and 4%, respectively, of the total weight of the 42 food wasted items. The water footprint and environmental impact of the household food waste resulted in 0.46 ± 0.04 m³ and 0.71±0.05 kg CO2eq, respectively. Beef, pork, poultry, and rice accounted for 52, 9, 5, and 4% of the total water footprint, while beef, pork, rice, tofu/cheese had 52, 8, 6, and 6% of the total emissions, respectively, embedded in the food wasted. Furthermore, the average estimated economic cost associated with wasted food items was 3855.93±527.27 Korean won, with beef, fish, and leafy vegetable responsible for 21, 13, and 10%, respectively, of the total economic cost. A combined assessment using water-environmental-economic nexus indicated that animal-based food had the highest footprint impacts, with beef, pork, and poultry indicating high indices of 0.3, 0.08, and 0.06 respectively, on a scale of 0 to 1, compared to corn and lettuce with lowest impacts of 0.02. Other food items had moderate impact values ranging from 0.03 to 0.05. This study, therefore, provides insight into the enormity of environmental and economic implications of household food waste among Korean households.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.6
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• pp.499-502
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• 2008

In this work, Ga-doped ZnO (GZO) thin films for gas sensor application were deposited on low temperature co-fired ceramics (LTCC) substrates, by RF magnetron sputtering method. The LTCC substrate is one of promising materials for this application since it has many advantages (e.g., low cost production, high manufacturing yields and easy realizing 3D structure etc.). The LTCC substrates with thickness of $400\;{\mu}m$ were fabricated by laminating 12 green tapes which consist of alumina and glass particle in an organic binder. The structural properties of the fabricated GZO thin film with thickness of 50 nm is analyzed by X-ray diffraction method (XRD) and field emission scanning electron microscope (FESEM). The film shows good adhesion to the substrate. The GZO gas sensors are tested by gas measurement system and show fast response and recovery characteristics to $NO_x$ gas that is 27.2 and 27.9 sec, recpectively.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.177-182
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• 2009

The purpose of this study is to investigate planning of urban energy supply systems configuration and operating conditions for the district heating and cooling system using combined heat and power system. Generally the district heating and cooling system has been known to one of the effective way for energy saving, cost reduction and demand side management of energy. Economical analyses were carried out and operating characteristics for some systems were examined in terms of GER factor which represents to the ratio of gas and electricity costs. Rates of the energy consumption and the $CO_2$ emission were compared from the system configuration of the energy supply system with new district cooling system with the conventional one.

• Resources Recycling
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• v.25 no.4
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• pp.23-31
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• 2016

It was found that there was no problem in recycling by-products (waste rock and tailings) from Yangyang iron mine themselves through matter conversion because they are not hazardous according to results of KSLT method. In case of using tailings as sub-materials of cement, it recommended the use of less than 3% tailings dosage not to exceed 0.6% of total alkali ($R_2O$) content based on standard quality of portland cement (KS L 5201). Non sintered eco-brick corresponding to class 1 quality of recycled clay brick (KS I 3013) can replace 15% of cement with tailings and 100% of general fine aggregate with waste rock from iron mine. As mentioned above, recycling the by-products (waste rock and tailings) as sub-materials of cement and non sintered eco-brick could gain both environmental and economic benefits, that is, reduction of scale and maintenance cost of tailing ponds, decrease of energy use and $CO_2$ emission.

• New & Renewable Energy
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• v.4 no.2
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• pp.45-51
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• 2008

The fuel cell system is environment-friendly and energy efficient system. Especially, the fuel cell cogeneration systems providing heat and electricity to buildings have been developed and applied to a lot of sites in the world to cope with the global warming and $CO_2$ emission problem. This paper presents the result of study on the economic evaluation with super-micro fuel cell (SMFC) cogeneration system by varying the floor area ($132m^2{\sim}331m^2$) of the house, whose system capacity ranges from 0.10 kWe to 0.50 kWe. The electricity demand, heat demand, saved energy cost, and the simple pay-back period have been simulated for the various capacities of fuel cell cogeneration system. As a result, this study suggests the fuel cell system’s capacity decision strategy for a given house area. Contrary to conventional design assumptions, the smaller capacity fuel cell cogeneration system is appropriate for the house of large floor area to defense the progressive electricity tax, and the larger capacity fuel cell cogeneration system is appropriate for the house of small floor area to sell the electricity.

• Agricultural and Biosystems Engineering
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• v.3 no.2
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• pp.79-84
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• 2002

The seawater involving diverse chemical elements was mixed with wasted coals to improve the quality. The thermal and chemical characteristics of these seawater-mixed coals were investigated and compared with those of original coals. The contents of MgO, $Na_2O$, and $K_2O$ were increased by mixing seawater in wasted coals. The content of $Na_2O$ in these coal samples was greatly increased due to the sodium, which was the main component of seawater. Thus, it was expected that fusion temperatures of these coal samples were decreased. Coal samples mixed with seawater showed that the rapid weight loss was started at the lower temperature than those of original coal samples. In these coal samples, the temperatures of maximum heat emission were lowered by average $61^{\circ}C.$. Thus, it is suggested that some chemical constituents of the seawater act an important role on lowering the ignition temperature of wasted coal. By mixing seawater into wasted coals, the calorific values were increased. Especially, calorific values were greatly increased in the coal samples of lower quality as Baksan A and B with the improvement of 15~20%.

• Journal of environmental and Sanitary engineering
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• v.23 no.3
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• pp.1-8
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• 2008

Currently, medical waste stoker incinerator is widely used in the emission control technology of health-care risk waste and miscellaneous contaminated waste. In the past, wet type control technology was used to remove the major harmful gaseous contaminants of medical waste such as HCl, $NO_x,\;SO_2$, CO, DUST, Dioxin. However, the treatment cost for wastewater was high and it has a disadvantage for frozen system during winter season. Therefore, in order to obtain effective treatment, the dry type control technology was developed and widely used to remove the gaseous contaminants. In this study, pre-coated bag filter using hydrated lime, ($Ca(OH)_2$), was applied to the dry type control system and the optimum dose of hydrated lime was investigated. The treatment results showed that the dust collection rate was approximately 26.7%. Moreover, the HCl removal rate using pre-coated bag filter ($50mg/sm^3\;Ca(OH)_2$) was 13.52%, which was significantly higher than 3.26% obtained from conventional bag filter.