• Journal of Soil and Groundwater Environment
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• v.21 no.2
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• pp.22-28
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• 2016

In order to evaluate landfill stabilization based on organic carbon, stoichiometric analysis and a biological methane potential (BMP) test based on modeling were performed at the 2^nd Sudokwon Landfill Site. Mass balance analysis through a BMP test proved to be more adaptable for evaluation, and it showed that 28.9% of landfill organic carbon was expected to remain by 2046, 30 years after landfill closure. The organic carbon ratio of total landfill waste for 2046 is forecasted as 2.9% in demolition waste and 5.1% in household waste, and, if one were to consider plastic as an organic waste, the ratios would increase to 15.9% and 28.3%, respectively. Therefore, it seems that organic matter biodegradation facilitating measures such as bioreactor landfill technology and preemptive recovery of combustible waste are necessary to shorten post closure management periods and to meet the landfill stabilization guidelines more safely.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.505_506
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• 2009

This paper presents effective operation methods for the battery energy storage applied to a microgrid. In an islanded microgrid, energy storage is needed to satisfy an energy balance between generation and consumption. The microgrid can be classified according to the ratio of the sensitive load and renewable energy source in the microgrid. For effective management of the battery energy storage, based on the classified microgrid, suitable operation methods for the battery energy storage system are provided from well-known battery applications.

• Journal of Korea Society of Waste Management
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• v.35 no.7
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• pp.600-605
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• 2018

In this study, the combustion characteristics were investigated based on the biodrying solid recovered fuel (SRF) in a 5 Ton/day scale combustion boiler. The composition of the combustion gas containing the biodrying SRF was analyzed, the particulate matter, and its HCl content was determined with the air pollutant process test method. Mass balance, carbon balance, and combustion efficiency were calculated according to the equivalence ratio (ER) method; the energy recovery efficiency of the combustion boiler was also analyzed. The overall combustion efficiency of the biodrying SRF was 97.3 % and the energy recovery efficiency was 80.2%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.5
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• pp.531-538
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• 1993

A 4-week energy balance study was conducted to estimate the energy expenditure (EE) of 16 primary school age boys and girls, 8 to 12 year age, by measurement of energy intakes and changes in body energy (BE) content (intake / balance technique), keeping their normal living pattern and eating behavior. Gross energy intake (GE) and fecal energy (FE) loss was measured by bomb calorimetry. Urinary energy (UE) loss was calculated from nitrogen excreted. Fat mass (FM) was determined from body density estimated from skinfold thickness. Mean constitutional ratio of carbohydrate, protein and fat for the total energy intake was 10.1 $\pm$1.8%, 12.2$\pm$0.1% and 17.1$\pm$2.0% for the boys and 74.0$\pm$1.7%, 10.7$\pm$0.3% and 15.3$\pm$0.5% for the girls, respectively. Fecal energy loss was 5.1% and 4.5% proportion of the gross energy intake for the boys and girls, respectively. Mean daily metabolizable energy estimated by subtract feral and urinary energy loss was 1862$\pm$15kcal for the boys and 1627$\pm$20kcal for the girls. Total body energy change estimated from body composition change over 28 days was increased 1524$\pm$539kcal for the boys and 3622$\pm$718kcal for the girls. Mean daily energy expenditure was 1812$\pm$37kcal(52 $\pm$2kcal/kg of body weight) for the boys and 1487$\pm$25kca1 (52$\pm$2kcal/kg of body weight) for the girls.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.1-8
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• 1992

A 4-week energy balance study was conducted to estimate the energy expenditure (EE) of 7 high school age men, 16 to 18 year of age, by measurement of energy intakes and changes in body energy (BE) content (intake/balance technique), keeping their normal living pattern and maintenance body weight. Gross energy intake (GE) and fecal energy (FE) loss was measured by bomb calorimetry, Urinary energy (UE) loss was calculated from nitrogen excreted. Fat mass (FM) was determined from body density estimated from skinfold thickness. 1) Mean constitutional ratio of carbohydrate, protein and Int for the total energy intake was $73.7{\pm}0.3%$, $13.5{\pm}0.3%$ and $12.9{\pm}0.5%$, respectively. 2) Fecal energy loss was 2.4% proportion of the gross energy intake. 3) Mean daily metabolizable energy estimated by subtract fecal and urinary energy loss was $2582{\pm}61\;kcal$. 4) Total body energy change estimated from body composition change over 28 days was decreased $4309{\pm}1837kcal$. 5) Mean daily energy expenditure was $2736{\pm}59kcal\;(46{\pm}1kcal/kg$ of body weight).

• Journal of Ocean Engineering and Technology
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• v.2 no.1
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• pp.176-182
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• 1988

The exergy analysis on the heat storage performance of the senible heat storage unit which consists of the heat storage material in the concentric annulus and the hot fluid flowing through the inner tube is performed. Heat transfer characteristics which are necessary for the performance of the exergy analysis is obtained from the energy balance equations and the second law of thermodynamics. As the index of heat storage performance, the exergy lossnumber $N_{s}$, and exergy storage ratio from the concepts of the second law of thermodynamics are defined. Results are ovtained for the grometry of the storage unit, the Biot number Bi, ambient temperature $T_{o}$ as parameters. From these results the exergy storage ratio can be considered as the efficiency of the hat storage unit and is introduced as a guide to design.

• Journal of Hydrogen and New Energy
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• v.24 no.5
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• pp.373-385
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• 2013

To obtain higher power efficiency of Residential Power Generation system(RPG), it is needed to operate system on optimized stoichiometric ratios of fuel and air. Stoichiometric ratios of fuel/air are closely related to efficiency of stack, reformer and power consumption of Balance Of Plant(BOP). In this paper, optimizing stoichiometric ratios of fuel/air are conducted through systematic experiments and modeling. Based on fundamental principles and experimental data, constraints are chosen. By implementing these optimum values of stoichiometric ratios, power efficiency of the system could be maximized.

• Journal of the Korean earth science society
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• v.34 no.6
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• pp.561-574
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• 2013

This study investigates energy fluxes measured near Gangjeong-Goryeong Weir of the Nakdong River of South Korea for more than a year, from July 2011 to September 2012, in order to analyze the applicability of the data for future impact analyses. Each of the two study sites is located in a rural area, surrounded by agricultural fields, and an urban industrial area. Sensible and latent heat fluxes are analyzed according to the wind direction. In the summertime, when the wind blows from the river, sensible heat tends to decrease and latent heat tends to increase at both sites. This result is considered to be caused by moisture transfer from the river. Bowen ratio, energy balance closure, momentum flux, and stability are analyzed as well. The Bowen ratio of the rural agricultural site turns out higher than that of the urban site regardless of the season. The energy balance closure is higher at the agricultural site compared to the urban area, which is mainly due to exclusion of the storage term calculation at the urban site. The momentum flux is greater at the urban site both in winter and summer. The instability lasts longer during daytime and in the summertime, when there is a strong turbulence. The data from these sites are appropriate to be used in analyzing the impact of river in surrounding areas for future studies.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.1
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• pp.15-19
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• 1988

Heat energy distribution forming net radiation above corn canopy was determined by means of the Bowen ratio-energy balance method. Total-global solar radiation above crop canopy during the growing season was $1,559MJm^{-2}$ and total latent heat flux density was $960MJm^{-2}$. The data showed that 61.6% of the global solar radiation was used for a heat source of evapotranspiration (ETa) above corn canopy. Mean daily ETa ranged from 2.7 to 5.6mm. Total ETa, total drymatter, and water use efficiency were 394mm, $2,214gm^{-2}$, and $5.6gm^{-2}mm^{-1}$, respectivively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.5
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• pp.563-569
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• 2012

An energy balance analysis is conducted for a 30 t thrust level liquid rocket engine. The relations between thrust and combustion pressure, between thrust and propellant flow rate, and between combustion pressure and fuel pump pressure rise are compared against those indicated by a published database of the existing rocket engines. A combustion pressure higher than the old design value is obtained, implying that the present design is high-performance oriented. The thrust to propellant flow rate ratio is the same as that of the existing engines, indicating that the specific impulse performance is at the usual level. The fuel pump pressure rise is found to be slightly high when the combustion pressure is considered, and it is attributed to the pressure budget of the present ground test engine not being optimized.