• Plant Journal
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• v.15 no.3
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• pp.35-41
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• 2019

In this study, we investigated the effect of the generation of NOx and CO by adjusting the overfire air supply position and ratio using the boiler that was converted from coal burning to wood pellet boiler. When the amount of the overfire air is relatively increased, the amount of NOx is slightly decreased but CO is sharply decreased when burning at low excess air ratio (1.10) that is due to a small fuel particle size. However, NOx slightly increased when burning at high excess air ratio (1.33) due to the large fuel size, but CO was hardly affected. Also, When the amount of overfire air was same, The more supply position was concentrated to upper portion of the main combustor, the more NOx and CO was lowered. And in case of the excess air ratio was high, the generation of NOx and CO I can see that it keeps the level irrelevant to the amount of air for the second stage combustion.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.3
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• pp.39-46
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• 2015

A numerical study has been conducted on CO after burning and NO generation of the rocket plume as the cooling water injected to the rocket plume. The present study shows that the cooling water has a role of increasing the degree of CO after burning and reducing NO generation. However the effect varies as the injection configuration of the cooling water. When the cooling water is injected at the side of the plume, NO generation is dramatically reduced while the degree of CO after burning is relatively low. When the cooling water is injected at the side and the center of the plume, CO after burning is highly increased and NO generation is also dramatically reduced.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.88-88
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• 2017

• Journal of Korea Water Resources Association
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• v.51 no.12
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• pp.1229-1235
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• 2018

We have examined dynamic relationships among water-efficiency, economic growth, electricity generation, and $CO_2$ emissions in Korea using various time-series analysis methods for 1990-2014. While previous studies have been limited to economic growth, $CO_2$ emissions, and electricity generation, this study contributed to explain the relationship between existing variables and water-efficiency. We find that the four variables reach a balanced state in the long run through short-term adjustment, $CO_2$ emissions and economic growth are responsible for water efficiency, and that $CO_2$ emissions, economic growth and water efficiency are the causes of electricity generation. The long-term impact coefficient estimates on water-efficiency show that the increase in electricity generation and the decrease in $CO_2$ emissions increase water-efficiency. Although economic growth has increased water-efficiency, moreover, we have identified an inverted U-shaped relationship between economic growth and water-efficiency, which suggests that economic growth above a certain level reduces the rate of increase in water-efficiency.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.821-824
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• 2009

LFG-MGT CHP system development project with $CO_2$ enrichment in greenhouses was introduced. LFG is produced from the anaerobic digestion of landfilled waste and it has been utilized for power/heat generation since it contains around 50% of $CH_4$. Utilization of LFG from small scale landfill is also needed as well as large scale landfill. However, due to economy of scale, it is very difficult to develop business model. In this context, combining CHP system with greenhouses is considered as feasible option for LFG utilization. LFG-MGT CHP system with $CO_2$ fixation in greenhouses has been derived as an active greenhouse gas reduction strategy, The focus of the system is beyond carbon neutral LFG utilization to neutral carbon absorption. The system is feasible in terms of direct and indirect $CO_2$ emission reduction with more economical way.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.242-245
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• 2008

In the power generation industry, various efforts are needed to cope with tightening regulation on carbon dioxide emission. Integrated gasification combined cycle (IGCC) is a relatively environment friendly power generation method using coal. Moreover, pre-combustion $CO_2$ removal is possible in the IGCC system. Therefore, much effort is being made to develop advanced IGCC systems. However, removal of $CO_2$ may affect the system performance and operation through reduction of fuel gas supplied to the gas turbine. This study predicts system performance change due to $CO_2$ capture by pre-combustion process from the normal IGCC performance without $CO_2$ capture and presents results of design parametric analysis.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.5
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• pp.557-565
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• 2022

The effect of flow configuration in ammonia-fed solid oxide fuel cell are investigated by using a three-dimensional numerical model. Typical flow configurations including co-flow and counter-flow are considered. The ammonia is directly fed into the stack without any external reforming process, resulting in an internal decomposition of NH3 in the anode electrode of the stack. The result showed that temperature profile in the case of counter-flow is more uniform than the co-flow configuration. The counter-flow cell, the temperature is highest at the middle of the channel while in the case of co-flow, the temperature is continuously increased and reached maximum value at the outlet area. This leads to a higher averaged current density in counter-flow compared to that of co-flow, about 5%.

• Asian Journal of Innovation and Policy
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• v.11 no.3
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• pp.363-396
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• 2022

This study focuses on the happiness of the generation MZ of innovative enterprises, which are evaluated as the driving force of economic growth at a time when the value of happiness is emerging. Happiness is related to the prosperity and performance of the organization. However, MZ generation office workers, who account for 45% of the economically active population, are considered unhappy at work. Therefore, this study attempted to explore the preceding factors (organizational factors, relationship and communication factors, and personal factors) of happiness for the generation MZ of innovative enterprises and to examine the effect of happiness on employee engagement. For the study, 300 usable responses were collected from generation MZ working in innovative enterprises through an online survey. Research hypotheses and research questions were verified using SPSS 26.0 and AMOS 23.0. As a result, it was confirmed that procedural justice among the organizational factors, rewarding co-worker/supervisor relationship among the relationship/communication factors, and personal factors (meaningfulness of work, personal accomplishment) positively affected the MZ generation's workplace happiness. In particular, the meaningfulness of work, which corresponds to personal factors, exerted the most significant influence. In addition, in the case of happiness at the workplace, there was a positive effect on employee engagement, which was stronger in organizational engagement than in job engagement. As a result of examining the structural relationship between variables used in the study, it was found that procedural justice, rewarding co-worker/supervisor relationships, the meaningfulness of work, and personal accomplishment positively affected employee engagement through happiness. Through research, the importance of happiness at the workplace was suggested by systematically reviewing the preceding variables of happiness at the workplace and grasping the positive effects of happiness. In addition, the management measure of generation MZ employees of innovative enterprises was discussed, the necessity of research on happiness at the workplace was emphasized, and follow-up studies were proposed.

• Journal of Environmental Health Sciences
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• v.45 no.1
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• pp.1-8
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• 2019

Objectives: The purpose of this study was to estimate the ventilation rate of residential homes in Korea through tracer gas methods using indoor and outdoor concentrations of carbon dioxide ($CO_2$) and $CO_2$ generation rates from breathing. Methods: In this study, we calculated the number of occupants in a home by time through data on the average number of people per household from the Korean National Statistical Office and also measured the amount of $CO_2$ generation by breathing to estimate the indoor $CO_2$ generation rate. To estimate the ventilation rate, several factors such as the $CO_2$ generation rate and average volume of residential house provided by the Korean National Statistical Office, indoor $CO_2$ concentrations measured by sensors, and outdoor $CO_2$ concentrations provided by the Korea Meteorological Administration, were applied to a mass balance model for residential indoor environments. Results: The average number of people were 2.53 per household and Koreans spend 61.0% of their day at home. The $CO_2$ generation rate from breathing was $13.9{\pm}5.3L/h$ during sleep and $15.1{\pm}5.7L/h$ in a sedentary state. Indoor and outdoor $CO_2$ concentrations were 849 ppm and 407 ppm, respectively. The ventilation rate in Korean residential houses calculated by the mass balance model were $42.1m^3/h$ and 0.71 air change per hour. Conclusions: The estimated ventilation rate tended to increase with an increase in the number of occupants. Since sensor devices were used to collect data, sustainable data could be collected to estimate the ventilation rate of Korean residential homes, which enables further studies such as on changes in the ventilation rate by season resulting from the activities of occupants. The results of this study could be used as a basis for exposure and risk assessment modeling.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.601-603
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• 2008

The main purpose of this study is to design and develop the information display device for power conditioning system of photovoltaic power generation system. The function of this device is to display the information, communicate with PCS controller and store the special information. The developed device is tested to verify the performance and experimental results show the excellent performance. An actual running test is being carried out to verify the reliability of the device including PCS by applying it to 10kW level photovoltaic power generation system established in Ulsan College.