• Proceedings of the Korean Society for Agricultural Machinery Conference
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• v.10 no.1
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• pp.76-82
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• 2005

This paper presents the combustion characteristics of hydrocarbon fuel from a conventional pressureswirl nozzle of a small-scale burner. The nozzle has orifice diameters of 0.256 mm and liquid flow rates raging from 50 to 64 mL/min were selected for the experiments. The furnace temperature distribution along the axial distance, the gas emission such as CO, $CO_2,\;NOx,\;S0_2,$ flue gas temperature, and combustion efficiency were studied. The local furnace and flue gas temperatures decreased with an increase in air velocity. At injection pressures of 1.1 and 1.3 MPa the maximum furnace temperatures occurred closer to the burner exit, at an axial distance of 242 mm from the diffuser tip. The CO and $CO_2$ concentrations decreased with an increase in air velocity, but they increased with an increase in injection pressure. The effect of air velocity on NOx was not clearly seen at low injection pressures, but at injection pressure of 1.3 MPa it decreased with an increase in air velocity. The effect of air velocity $SO_2$ concentration level is not well understood. The combustion efficiency decreased with an increase in air velocity but it increased with an increase in injection pressure. It is recommended that injection pressure less than 0.9 MPa with air velocity not above 8.0 m/s would be suitable for this burner.

• Journal of the Korea Institute of Building Construction
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• v.12 no.2
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• pp.194-202
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• 2012

This paper predicts the cementing efficiency of fly-ash(FA) based on mortar test considering binder-water ratio and FA replacement ratio as experimental variables. The cementing efficiency prediction model proposed by statistical analysis enables us to estimate the value according to the binder-water ratio and FA replacement ratio of matrix. When FA replacement ratio is the same, the lower the binder-water ratio, the higher the estimated cementing efficiency. There are significant differences in the values according to binder-water ratio at FA replacement ratios of 15% or less, but there are almost no differences when FA replacement ratio is more than 15%. As the binder-water ratio increases, the variations in the values according to FA replacement ratio are great at FA replacement ratios of 15% or less. As the FA replacement ratios increase, the values increase for FA replacement ratios of 15% or less, but decrease for more than 15%. The values range from -0.71 to 1.24 at binder-water ratio of 1.67-2.86 and FA replacement ratio of 0-70%. The RMSE of the 28-day compressive strength predicted by modified water-cement ratio is 2.2 MPa. The values can be trusted, as there is good agreement between predicted strength and experimental strength.

• Journal of Environmental Science International
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• v.27 no.2
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• pp.99-107
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• 2018

In order to design the improvement process for T-N removal, the treatment process of Suyoung, Gangbyeon, and Noxan sewage treatment plants (STP) in Busan was anlayzed. Suyoung STP shows a T-N removal efficiency of about 69.8% with MLE(Modified Ludzack ettinger) and A2O+MBR. However, it is necessary to improve the process to maintain over DO of 1 mg/L and is required to install a flow control tank to minimize the rainfall effect. Gangbyun STP shows a about 70.2% T-N removal efficiency with A2O+GFF(gravity fiber filtration). However, in order to improve T-N removal efficiency, it is needed to install MLE process to treat recycle water. Noksan STP shows a T-N removal efficiency of about 71.0% with MLE+Chemical treatment and shows stable T-N concentration in effluent. However, it is required a toxic chemical management process because bad wastewater flows into the STP, also is necessary a process improvement in order to increase internal recycling ratio. Especially, it is required a process improvement to increase HRT of nitrification tank because Suyoung and Gangbyeon STPs shows low nitrification efficiency during winter season.

• Journal of Navigation and Port Research
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• v.42 no.2
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• pp.107-116
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• 2018

Planning strategies to achieve higher competitiveness of ports are becoming increasingly important in business environment. Therefore, strategic competitive position and efficiency analysis needs to be performed to increase ports' effectiveness and competitiveness. This matches with one of targets of new concept e-Navigation to increase the agility and efficiency of ports. The purpose of this study was to apply Boston Consulting Group matrix to analyze competitive positioning of major ports in Korea and China in term of several main cargo types and then use a combination of Data Envelopment Analysis and Principal Component Analysis model to calculate efficiencies. Results show that, at the moment, Chinese ports are still on the top with high position and efficiency score for the representative-Shanghai port. However, result also points out that except container type, Korean ports have chance to compete in other cargo types. Moreover, Gwangyang port is regarded as efficient. It has better position time. It is believed that Gwangyang port together with Busan port can compete with Chinese port in the near future.

• Journal of the Korean Solar Energy Society
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• v.25 no.4
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• pp.85-92
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• 2005

One of the most effective methods for utilizing solar energy is to combine thermal solar and optical energy simultaneously using a hybrid panel. Many systems using various kinds of photovoltaic panels have already been constructed. But utilizing solar energy by means of a hybrid panel with concentrator has not been to be attempted yet. Normally if sunlight is directed on the solar cell, and there is no increase in temperature, the absorption energy of each cell will increase per unit area. In a silicon solar cell. however, cell conversion efficiency decreases according to the increasing temperature. Therefore, to maintain cell conversion efficiency under normal condition, it is necessary to keep the cell at operating temperature. we design and make new hybrid panel with cooling system to prevent increasing of temperature on cell, collect effectively thermal energy. We compared performance of new hybrid panel with PV module and thermal panel. We also evaluated conversion efficiency, electric power and thermal capacity and confirmed cooling effect from thermal absorption efficiency.

• Journal of Wellbeing Management and Applied Psychology
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• v.5 no.2
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• pp.21-27
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• 2022

Purpose: This study is about photocatalytic technology and plasma oxidation-reduction technology. To the main cause of exposure to odor pollution, two deodorization techniques were applied to develop a module with higher removal efficiency and ozone reduction effect. Research design, data and methodology: A composite module was constructed by arranging two types of dry deodorization equipment (catalyst, adsorbent) in one module. This method was designed to increase the responsiveness to the components of complex odors and the environment. standard, unity, two types of oxidizing photo-catalyst technology and plasma dry deodorization device installed in one module to increase the potential by reduction to 76% of ozone, 100%, and 82%. Results: The complex odor disposal efficiency was 92%. Ammonia was processed with 50% hydrogen sulfide and 100% hydrogen sulfide, and ozone was 0.01ppm, achieving a target value of 0.07ppm or less. The combined odor showed a disposal efficiency of 93%, ammonia was 82% and hydrogen sulfide was 100% processed, and ozone achieved a target value of 0.07 ppm or less. Conclusions: Ozone removal efficiency was 76% by increasing Oxidation-Reduction Reaction(ORR). The H2S removal efficiency of the deodorizer was higher than that of the biofilter system currently used in sewage disposal plants.

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.6
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• pp.470-476
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• 2021

In the near future, with the urgent requirement of environmental protection, hydrogen based energy system is essential. However, at the present time, most of the hydrogen is produced by reforming, which still produces carbon dioxide. This study proposes a high-power electrolytic hydrogen production system based on solid oxide electrolysis cell with no harmful emissions to the environment. Besides that, the parametric study and optimization are also carried to examine the effect of individual parameter and their combination on system efficiency. The result shows that the increase in steam conversion rate and hydrogen molar fraction in incoming stream reduces system efficiency because of the fuel heater power increase. Besides, the higher Faraday efficiency does not always result a higher system efficiency.

• Journal of Fashion Business
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• v.26 no.1
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• pp.53-67
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• 2022

The purpose of this study was to compare the appearance similarity between a 3D virtual wedding dress, and a model wearing real dress, and production efficiency, and the possibility of achieving similar results with 3D digital technology. Five wedding dresses for small weddings under the theme of 'Dream Series', were designed and produced in virtual and real dresses to quantitatively compare and analyze the appearance similarity and production efficiency. Experts compared the appearance similarity on the silhouettes, colors, materials, and details, and production efficiency was compared with time and cost. Based on our results, 3D virtual images of four out of the five dresses were similar to the real images. Our efficiency evaluation results showed that the manufacturing time was 45.4% shorter, and the manufacturing cost was 46.1% less than the existing method. This indicated that the wedding dress manufacturing process using 3D virtual software was time and cost saving competitive. Our results also confirmed that 3D virtual software technology has the potential to increase the efficiency of designing and production, and therefore an increase in competitiveness and sales of wedding dresses. Furthermore, 3D technology allows consumers to select and order wedding dresses online through 3D virtual software. This is a great advantage, and it highlights the significance of this research study.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.869-877
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• 2020

The power consumption in the low consistency (LC) refining is an important indicator for the optimal control of the process and it is composed of the net power and the no-load power. The refining efficiency and process characterization of LC refining are directly affected by power consumption. In this paper, the effect of pulp consistency and average fiber length on the power consumption and refining efficiency were studied through the LC refining trials conducted by an experimental disc refiner. It is found that the curve of power-gap clearance can be divided into constant power section, power reduction section, and power increase section. And the no-load power and the adjustable domain of loading applied by the refining plates will increase as the increase of pulp consistency, while the increase of net power is larger than that of no-load power which makes the increasing of refining efficiency. Meanwhile, the adjustable domain of loading applied by the refining plates can be slightly improved by increasing the average fiber length, but its effect on the no-load power in the LC refining process can be neglected. The study of power consumption in LC refining is of positive significance for the proper selection of pulp properties in LC refining, in-depth exploration of refining mechanism, and energy consumption reduction in refining.

• Journal of the military operations research society of Korea
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• v.35 no.2
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• pp.99-117
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• 2009

Energy is essential factor of production for a firm to produce goods and services. If so, what is the condition of maintaining profit of a firm when energy price is going up? In conclusion, the condition is that the rate of productivity improvement should be greater than the rate of energy price increase. To put this concretely, when the elasticity of energy price as to the productivity improvement is greater than the weight of the energy cost on to the total revenue of the firm, the firm can escape the negative effect of energy price increase. This is that, saying that once more, the firm have to reduce the energy cost or promote energy efficiency to maintain appropriate or sufficient profit when energy price is going up fast. Therefore, in this study we will analyze the effect of the oil price increase on the energy saving investment and that of energy saving investment on the energy efficiency in the field of Korean manufacturing industry. In doing so, this study could show that the effect of energy price increase on the energy efficiency of the firm and the factor of that mechanism.