• Solar Energy
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• v.11 no.1
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• pp.27-40
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• 1991

Research and development works on practical application of natural energy utilization systems involving solar, wind and sea wave energies are under promoting for the purpose of improving the energy consumption structure. These natural energies, made available with the use of relatively simple apparatus, are clean economically efficient and highly effective in the conservation of environment. However, these natural energies also have low energy density, randomness and regional variations. To compensate for these characteristics, hybrid utilization of solar and wind energies is currently under study. The introduction of a plural number of the natural energy hybrid utilization systems into a specific area will affect the economic efficiency, reliability and environmental conservation. Evaluation method of such effects has been examined in this study. The present method consisted of the steps described below. First, available energy was calculated from insolation distribution and wind velocity distribution in the specified area, and then the effect on the configuration of the power system load was obtained. This was followed by the determination of the optimal power dispatch over the specified period and by evaluations in light of economic efficiency, reliability and environmental indices.

• Journal of Convergence for Information Technology
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• v.9 no.5
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• pp.14-20
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• 2019

Energy saving is becoming more and more important issue due to lack of resources and limited nature. However, There is a lack of learning status on energy saving in the school field. In particular, in elementary education on energy saving was not linked to practice, and the educational effect was insufficient. Although various kinds of learning tools are utilized, many successful cases of energy saving game strategy are introduced in overseas industry field, and game design is proposed so that energy related education can be played through games. Because energy conservation can not be effective without practice, learning using games as a tool is expected to be more effective than learning based on knowledge transfer in the classroom. We propose a defense game for energy conservation education by using the mission elements, score acquisition element, time limit element, and character element which are the interesting elements of the game designed in the previous research.

• Journal of Conservation Science
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• v.36 no.2
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• pp.82-92
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• 2020

Modern artworks are constructed using a variety of materials and techniques. Sculptures, which predominantly consist of metals, usually have different shapes and consist of different material mixtures. The structural and material properties of these sculptures are often controlled by conservation treatment methods. However, the application of existing treatment methods is challenging at times, indicating that more diverse treatment materials and techniques are necessary. Therefore, in this study, a treatment method that employs volatile corrosion inhibitor(VCI) powder, rather than an anti-corrosion solution, for the conservation and management of metal artworks was used. VCI powder and VCI films containing VCI powder were used, and the results obtained confirmed that both of them showed anti-corrosion effect. Only a slight change in the chromaticity of metal samples was observed, and compared to the untreated samples, the application of the VCI powder resulted in a decrease in the rate of corrosion by half. Moreover, VCI film tests revealed that comparing to the untreated or polyethylene film-treated samples, VCI film treatment resulted in a decrease in the occurrence of corrosion compounds. The contact angle, surface energy, and surface electrical resistance were measured, and the evaluation of these surface properties established the anti-corrosion effect of VCI. Additionally, direct application of VCI and VCI films on actual sculptures further confirmed the anti-corrosion effect of VCI.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.123-129
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• 2009

In these days, the green building movement caused by the energy crisis is increasing, passive design is getting mere and more attention as it provides many possibilities for energy conservation. Moreover, with the increasing social intention for healthy life, the demand for indoor air Quality is increasing in Korea. As result, the ventilation system which can provide the sound outdoor air constantly has been obliged in Korea. So, the hybrid system which using natural power and mechanical power and makes up for the shortage of mechanical and natural ventilation attracts people's attention in Korea. As a hybrid ventilation system, in this study, the stack effect driven hybrid ventilation system in high-rise residential building will be suggested. And in this paper, the theoretical review for hybrid ventilation system suggested in this study will be addressed. Especially, the characteristics of pressure distribution and airflow caused by stack effect in high-rise residential building and the possibility of natural ventilation as results of stack effect will be described.

• Journal of Conservation Science
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• v.26 no.4
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• pp.377-383
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• 2010

The effect of gamma irradiation on the microbial growth inoculated in the Korean traditional paper, Hanji, was investigated. Also, the mechanical properties of Korean traditional paper were measured to verify the possible change by gamma radiation. Bacillus cereus and Aspergillus niger were cultivated and the spores were innoculated in papers at the 250,000 and 500,000 colonies, respectively. In these results, 5log spores of B. cereus could be all inactivated at the dose of 6 kGy, and 5log A. niger be inactivated at 8 kGy, respectively. There was also showed no significant change in tensile strength, bursting strength and color index of Korean traditional paper by the gamma irradiation upto the dose of 50 kGy. These results confirmed that radiation treatment of Korean traditional paper is extremely efficient and could be used to preserve ancient books and archives documents from being damaged by moulds and fungi.

• Coupled systems mechanics
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• v.6 no.2
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• pp.157-174
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• 2017

In the present investigation reflection and transmission of plane waves at an elastic half space and piezothermoelastic solid half space with fractional order derivative is discussed. The piezothermoelastic solid half space is assumed to have 6 mm type symmetry and assumed to be loaded with an elastic half space. It is found that the amplitude ratios of various reflected and refracted waves are functions of angle of incidence, frequency of incident wave and are influenced by the piezothermoelastic properties of media. The expressions of amplitude ratios and energy ratios are obtained in closed form. The energy ratios are computed numerically using amplitude ratios for a particular model of graphite and Cadmium Selenide (CdSe). The variations of energy ratios with angle of incidence are shown graphically. The conservation of energy across the interface is verified. Some cases of interest are also deduced from the present investigation.

• Journal of the Korean Solar Energy Society
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• v.22 no.4
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• pp.26-34
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• 2002

Daylighting in building is very important as it has an effect on work performance as well as on their visual health. It is also regarded as a good energy conservation measure in saving energy used for lighting. There are many daylighting evaluation tools such as empirical equations, tables, nomograms, diagrams, protractors, computer simulation, scale models. This study conducted initial daylight measurements to analyze luminous environment in classrooms of elementary school and comparative analysis on three daylighting evaluation tools, such as daylight factor calculation formula, the graphic method with BRE Protractor and computer simulation with Adeline 3.0. It is found that the computer simulation tool produced the closest result to actual measurements of luminous environment in elementary school classroom, and the other simplified tools made appropriate results so that they can be used in the early stage of daylighting design process.

• Earthquakes and Structures
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• v.18 no.6
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• pp.743-752
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• 2020

The phenomenon of reflection and transmission of plane waves at an interface between fluid half space and orthotropic piezothermoelastic solid half-space with two-temperature has been investigated. Energy ratios of various reflected and transmitted waves are computed with the use of amplitude ratios. The law of conservation of energy across the interface has been justified. It is found that the energy ratios are the functions of angle of incidence, frequency of independent wave and depend on the different piezothermoelastic material. A piezothermoelastic material has been considered which is in welded contact with water. Variations of energy ratios corresponding to the reflected waves and transmitted waves are computed and shown graphically for the two different models. A particular reduced case of interest is also discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.9
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• pp.1093-1100
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• 2004

Numerical analysis of the heat transfer associated with droplet impact on a hot solid surface is performed by solving the equations governing conservation of mass, momentum and energy in the liquid and gas phases. The deformed droplet shape is tracked by a level set method which is modified to achieve volume conservation and to include the effect of contact angle at the wall. The numerical method is validated through the calculations for the cases reported in the literature. Based on the numerical results, the heat transfer rate is found to depend strongly on the droplet spread radius. Decreased advancing/receding contact angles enlarge the splat radius and in turn enhance the wall heat flux. The effect of impact velocity on the droplet spread is reduced as the droplet size decreases. Also, droplet atomization is observed to significantly enhance the heat transfer rate and the effect is pronounced for a smaller size of droplet. An existing model equation to predict the maximum spread radius is improved for application to a micro droplet.

• Journal of the Korean Society of Safety
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• v.26 no.4
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• pp.102-110
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• 2011

For decreasing of the casualties and designing of the smoke control systems in the ultra high-rise building, the programs for analysis of smoke control were developed for prediction of smoke spread and distributions of pressure and temperature in building fire situation. In this study, coupling algorithm between mass and enthalpy conservations was modified for improving the applicability of the CAU_ESCAP which program can consider the energy transfer. The fire situation in ultra high-rise building was applied by using the modified CAU_ESCAP. Results of pressure difference predicted by modified CAU_ESCAP are higher than results of ASCOS as stack effect is generated due to the increasing of stairway temperature. Moreover, theoretically, the result of the neutral plane is more accurate than the result of ASCOS, in fire situation of ultra high-rise building.