• Proceedings of the Korean Radioactive Waste Society Conference
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• 2019.05a
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• pp.209-210
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• 2019

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.301-302
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• 2018

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.1 no.1
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• pp.93-103
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• 2003

IAEA, FT-04-020, and ANS 16.1, standard leaching test methods, were evaluated comparatively with their test results. Leaching index of $^{60}$ Co and $^{137}$ Cs by ANS 16.1 method for waste forms of paraffin and cement were above 6.0. Their leaching behavior were depending on the type of matrix and leachant. Leachability of $^{60}$ Co for cement waste form was higher in simulated seawater than do-mineralized water, and was higher in de-mineralized water for paraffin waste form. leachability of $^{60}$ Co was contrary to $^{137}$ Cs. Cumulative fraction leached of $^{60}$ Co was higher in order or IAEA ＞ ANS ＞ FT in a cement waste form.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.3
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• pp.328-336
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• 2017

The exit surface of a lens is designed using a three-dimensional free-form expression in order to easily modify a curved surface. This enables the design of numerical values and mathematical things using three-dimensional free-form expression, and enhances precision because it can be fine-tuned via numerical control. The standard of "Classification of Luminaire Light Distribution" for outdoor lighting fixtures by IESNA is adopted in order to examine the correlation between three-dimensional free-form surface expression and lighting performance. The variation of light distribution type and range is analyzed using the values of maximum light intensity and 50% light intensity. The actual tolerance occurs owing to parameters such as the thickness of the lens, the distance between LEDs, and the movement of the center of the incident surface; the effects of changes in these parameters on the performance are compared and analyzed.

• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.416-423
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• 2015

It had been disputed how to apply wall drag to the dispersed phase in the framework of the conventional two-fluid model for two-phase flows. Recently, Kim et al. [1] introduced the volume-averaged momentum equation based on the equation of a solid/fluid particle motion. They showed theoretically that for dispersed two-phase flows, the overall two-phase pressure drop by wall friction must be apportioned to each phase, in proportion to each phase fraction. In this study, the validity of the proposed wall drag model is demonstrated though one-dimensional (1D) simulations. In addition, it is shown that the existing form loss model incorrectly predicts the motion of the dispersed phase. A new form loss model is proposed to overcome that problem. The newly proposed form loss model is tested in the region covering the lower plenum and the core in a nuclear power plant. As a result, it is shown that the new models can correctly predict the relative velocity of the dispersed phase to the surrounding fluid velocity in the core with spacer grids.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.263-264
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• 2017

• Journal of Contemporary Eastern Asia
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• v.19 no.1
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• pp.59-83
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• 2020

This paper examines the actions and the factors driving those actions to reduce energy consumption and enhance energy efficiency taken by United States cities. While not much empirical evidence is available on why governments pursue practical sustainability actions, we attempt to shed more light on this important topic by empirically identifying factors that contribute to concrete actions toward sustainability policies. We adopt political market theory as a basic theoretical framework with policy-making applied to city energy consumption. Using the 2010 ICMA (local government sustainability policies and program) data, this study expands the focus of analyses to evaluate the effect of the form of government on energy consumption and energy efficiency by using multiple regression analysis. The findings show that at the city level, the mayor-council form of government are negatively associated with governments' efforts to reduce energy consumption. However, cities with at-large elections and municipal ownership are more likely to adopt sustainability actions. We also find that a large-scale economy has significant effects on the effort to reduce city energy consumption and improve energy efficiency. This shows that environmental policies are directly connected to locally relevant affairs, including housing, energy use, green transportation, and water. Thus, local level administrators could take an executive role to protect the environment, encourage the development of alternative energy, and reduce the use of fossil fuel and coal energy. These efforts can lead to important environmental ramifications and relevant actions by municipal governments.

• Bulletin of the Korean Chemical Society
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• v.10 no.3
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• pp.247-250
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• 1989

The molecular structure of cyclobutylmethyl ketone (c-$C_4H_7COCH_3$) has been investigated by molecular mechanics II (MM2). For the monosubstituted cyclobutane there are two possible ring conformations, the equatorial and axial form, but for the cyclobutylmethyl ketone the equatorial form is predominant conformation. For the $COCH_3$ moiety there are two stable orientations which are the equatorial-gauche and the equatorial-trans form. The equatorial-gauche form where the C = O bond is nearly eclipsing (torsional angle ${\angle}C4-C3-C2-O10=14.5^{\circ}$) one of the ${\alpha}$C-C bonds of the four-membered ring was preferred conformer with steric energy of 13.37 kcal/mol. The equatorial-trans form where the C = O bond is nearly eclipsing (${\angle}C4-C3-C2-O10=145.0^{\circ}$) the ${\alpha}$ C-H bond of the four-membered ring was less stable conformer with steric energy of 15.40 kcal/mol.

• Journal of the Korean Solar Energy Society
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• v.30 no.2
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• pp.22-32
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• 2010

The world is facing environmental problem described as climate change and exhaustion of fossil fuel. In order to solve theses problems, importance of renewable energy is extremely growing. For stable energy supply, it is need to apply hybrid renewable energy systems in urban-scale, because some renewable energy system' outputs are greatly influenced by climatic condition. Especially, solar irradiation and wind velocity are influenced by urban geometric environment as well as climatic condition. Therefore it is necessary to evaluate the renewable energy potential according as urban form. This study aims to evaluate the potential of solar energy and wind energy in urban-scale and classify urban type according as characteristics of urban forms. The results of this study will be used to develop renewable energy system application guidelines for urban and energy planning.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.42-45
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• 2006

A new and reusable energy source is water-treatment sludges. There is a significant need for understanding the characteristics of sludge combustion related to improving efficiency and ensuring the safety of this new energy source. Because sludges are composed of solids and gas mixture, the combustion of the mixture may become quite complex. Not only decomposition of conventional organic elements but also dust explosion may be important during the process of converting sludges into a new and safe form of energy. Sludge combustion mainly involves hydrogen, methane, hydro carbons, carbon, and organic particles. Dust explosion during the gasification stage may depend on the surrounding temperature and the composition of gases. The uncertainty in the explosive behavior of energetic source is noted in this work. We study the explosion characteristics of sludge combustion while the reusability of sewage sludges as a new form of energy is also investigated.