• Applied Chemistry for Engineering
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• v.3 no.2
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• pp.327-334
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• 1992

As a promising method for the volume reduction of the low-level liquid waste, the pervaporation process was studied using a cellulose acetate membrane. Experimental results showed that the pervaporation method, usually applied to separation of organic materials, has a good decontamination effect for the volume reduction of liquid waste and the evaporation rate of water in this process was markedly faster than that of natural evaporation method, a wide-used process for the volume reduction of liquid waste. Depending on the feed solution conditions, the pervaporation characteristics were evaluated by the experimental results and the optimum conditions for preparation of the cellulose acetate membrane were established to increase the pervaporation flux through the membrane.

• Journal of Hydrogen and New Energy
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• v.21 no.4
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• pp.301-306
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• 2010

The present work is performed to photocatalytically reduce Cr(VI) by means of metal deposited anodized $TiO_2$ tubes, which are prepared by anodization of Ti foil followed by metal deposition. Stably immobilized photo-reactive materials are favored in the field of detoxification in a conventional aqueous medium, preventing gradual loss of efficiency and process malfunction due to detachment of the materials. The prepared samples are characterized by SEM, TEM, EDAX, and photocurrent. The metal deposited-$TiO_2$ electrode shows higher efficiency for Cr(VI) reduction (ca. 20%) and higher ability for adsorption (4~5 times) than pure one.

• Journal of the Korean Solar Energy Society
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• v.31 no.1
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• pp.100-106
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• 2011

This study proposes a $CO_2$ emission reduction method through correlation analysis of a sample building. First, energy saving factors of heating, cooling, lighting were determined for the correlation analysis and $CO_2$ emission contribution rate of the design parameters have been analyzed. Then optimal combination of each design parameter has been drawn. Heat transfer coefficient of walls and windows, air permeability, windows area ratio, and shading devices were selected as applicable energy saving factors of the sample building. Also computer simulation was conducted using experimental design by Orthogonal Arrays of the statistical method. And the contribution rate was estimated by Analysis of Variance-ANOVA. As a result, the $CO_2$ emission in heating was reduced to 51.9%; in cooling to 16.8%; and in lighting to 2% compared to the existing building. The majority of the reduction was presented by heating energy.

• Journal of Hydrogen and New Energy
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• v.32 no.1
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• pp.53-62
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• 2021

Batch type reduction-oxidation tests were performed to check effects of temperature, pressure, gas velocity, and capacity on reduction characteristics of mass produced particle in a 0.5 MWth chemical looping combustion system. The fuel conversion and the CO2 selectivity increased as the temperature increased and as the gas velocity decreased. However the CO2 selectivity showed the maximum and decreased as the capacity increased because the CO emission increased. The results show that high temperature, low gas velocity and low inert gas concentration are preferable to ensure high reactivity of oxygen carrier in the fuel reactor.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.187-192
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• 2009

Nowadays, global warming and high oil prices were a threat to the survival of the whole human race. One of a solution to respond to these problems is to reduce energy consumption of building. By adopting energy-saving design, the dissemination of low energy building is required. Therefore, to improve energy efficiency while reducing the usage of the design method is necessary to study actively. BIM-based systems applied to buildings, scheduled to be built by reducing the amount of energy reduction technologies can be analyzed. Depending on various design and equipment to set energy savings goals, you can select an alternative. If it is possible to predict the energy efficiency from the initial stage of design and support designing low energy building, we would be able to expect improvement in the economics of housing due to the reduction of energy consumption.

• Journal of Environmental Science International
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• v.15 no.5
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• pp.493-501
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• 2006

The increase in environmental loads and energy consumptions has resulted in the need of developed new forms of energy for a sustainable use for the society. Recently, the viability of using unused energy has attracted a great deal of attention. From the view point of using unused energy, the most critical problem can be referred to as the distance between the heat source/sink and heat demand area. The water resource in the city water system was used to solve this distance problem with unused energy. The calculation method of the potential use unit was used to survey the potential of the water resource in the city water system. The amount of theoretical unused energy and energy savings in the model city were estimated using this method. It is estimated that the amounts of energy savings and $CO_2$ reduction correspond to 131.3 GWh and 29280[t-C], respectively, per annual basis.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.270-270
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• 2002

• Journal of Hydrogen and New Energy
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• v.29 no.5
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• pp.450-457
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• 2018

To design the practical core-shell electrocatalysts, combination of core and shell materials is important to meet catalytic activity and durability target. In general, Pd is considered as a good core material due to its best activity caused by strain/ligand effect. Preparing Pd nanoparticles can be a starting point in fabricating core-shell type electrocatalysts, much simplified Pd preparing process is suggested by using carbon monoxide (CO) as a reducing agent and/or capping agent. The solvent composition and reaction temperature can control to nanosheet, tetrahedron, and sphere without using additional stabilizer. Among them, Pd nanosheet which has mainly (111) plane showed about 3 times higher electrocatalytic activity for oxygen reduction reaction (ORR) to the spherical Pd nanoparticles. The enhanced ORR activity of Pd nanosheets can be attributed to the exposure of Pd (111) surface and the high electrochemical surface area. Therefore, we demonstrated that the shape of Pd nanomaterials is easily controlled via a facile reduction method using CO, and (111) plane-oriented Pd nanosheets can be a promising ORR catalysts and core material for polymer electrolyte fuel cells (PEFCs).

• KIEAE Journal
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• v.12 no.3
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• pp.89-94
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• 2012

The international community is paying close attention to the climatic changes caused by the meteorological anomalies. In response to such phenomena, after the adoption of the United Nations Framework Convention on Climate Change in 1992, efforts to actively respond to the meteorological changes are proliferating all over the world; even in the Republic of Korea, the issue to tackle the meteorological changes has emerged as a top-priority national agenda. In the year of 2008, after the declaration of the low-carbon, green-growth paradigm by the government, the UNFCCC COP15 has announced a 30% reduction target of the emission of the greenhouse gases by 2020 as compared to the "Business As Usual, BAU" and has also confirmed, as a commitment plan to achieve reduction in the emission of greenhouse gases, the reduction target of greenhouse gases for all sectors, industries and years. (26.9% for buildings) Since the construction of the new apartment houses in the year of 2001, the "Building Energy Efficiency Rating", has been applied to newly constructed building complexes, built in 2010; the accumulated emission reduction has been evaluated at around 450,000toe and the accumulated carbon dioxide emission reduction is at $826,000tCO_2$ And through the prediction of these values under various scenarios (New construction, new construction / expansion of existing uses, when transferred to 1stgrade), the effects on the degree of reduction of greenhouse gases by the increased certification of the Building Energy Efficiency Rating are an alyzed and it is our aim to express the importance of the certification system capable of carrying out a quantitative evaluation of the building energy in order to establish the strategy to reduce the emission of carbon dioxide.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.3
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• pp.126-132
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• 1996

In this paper, the complexity reduction method for QCELP speech coder (IS-96) without any perfomrance degradation is proposed for the vecoder of CDMA digital cellular system. The energy terms in pitch parameter search and codebook search routines that require large computations are calculated recursively by utilizing the overlapped structure of code vectors in adaptive codebook and excitation codebook. The additional complexity reduction in the codebook search routine can be achieved by using a simple form in calculation of the energy term when the initial codebook value is zero. In the case of lower transmission rates such as 4,2,1 kbps, the complexity reduction by recursive calulations of energy term is increased.