• Journal of the Korean Institute of Gas
• /
• v.21 no.3
• /
• pp.53-60
• /
• 2017

Various researches have been conducted for the reduction of NOx at the combustion furnace and exhaust gas recirculation method is commonly used technology for NOx reduction. The present research adopted coanda nozzles at the outside pipes of furnace to entrain the exhaust gas for the exhaust gas recirculation and the mixed gas was ejected to the tangential direction to cause the swirl flow in the furnace. The combustion flow characteristics in the exhaust gas recirculation burner with coanda nozzle has been elucidated by analyzing the swirl flow streamlines, temepraure and reaction rate distribution in the furnace. The exhaust gas entrained flow rate has been investigated by changing the excess air factor and coanda nozzle gap and the exhaust gas entrained flow rate increased with the increase of excess air factor and it decreased with the increase of coanda nozzle gap. The mean temperature at the exit plane of exhaust gas decreased with the excess air factor and it was little affected by the increase of coanda nozzle gap. The NOx mass fraction at the exhaust gas exit plane remarkably decreased with the excess air factor and it was also little affected by the increase of coanda nozzle gap.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.5
• /
• pp.842-847
• /
• 2012

This study was conducted to estimate the greenhouse gas emissions on local government levels from 1990 to 2010 using 2006 IPCC guideline methodology. To calculate greenhouse gas emissions based on the 16 local governments, emission factor and scaling factor were used with default value and activity data came from the food, agricultural, forestry and fisheries statistical yearbook of MIFAFF (Ministry for Food, Agriculture, Forestry, and Fisheries). The total emissions in crop sector gradually decreased from 1990 to 2010 due to a decline in agricultural land and nitrogen fertilizer usage. The annual average emission of greenhouse gas was the highest in Jeonnam (JN) with 1,698 Gg $CO_2$-eq and following Chungnam (CN), Gyungbuk (GB), Jeonbuk (JB) and Gyunggi (GG). The sum of top-six locals emission had occupied 83.4% of the total emission in cropland sector. The annual average emissions in 1990 by applying 2006 IPCC guideline were approximately 43% less than the national greenhouse gas inventory by 1996 IPCC guideline. Jeonnam (JN) province occupied also the highest results of greenhouse gas emission estimated by gas types (methane, nitrous oxide and carbon dioxide) and emission sources such as rice cultivation, agricultural soil, field burning of crop residue and urea fertilizer.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.2
• /
• pp.189-194
• /
• 2016

This paper deals with the economic effects for the Surion(KUH-1) research and development program. The economic effects was measured by Inter-industry analysis method for production-inducing effects, value-added inducement effects, and job-creation effects and by estimating actual domestic input cost. In addition, technical riffle effects was analyzed for aerospace industry, defense industry and commercial industry market through similarity and contribution of technology.

• New & Renewable Energy
• /
• v.6 no.2
• /
• pp.33-39
• /
• 2010

The objective of this study is to present a basis for the evaluation on the renewable energy dissemination program in Korea applying the outcome evaluation, one of the five types of evaluation methods of EERE, DOE, and the effectiveness indicator, which is suggested by IEA, OECD. The outcome evaluation quantifies achievements of program outputs and outcomes against planned time frame. We analyze the correlation coefficients between cumulative expenditure on the renewable energy dissemination program and each renewable energy deployment and the unit installation cost of several dissemination programs for the outcome evaluation. Meanwhile, the effectiveness indicator is calculated by dividing the additional renewable energy deployment achieved in a given year by the remaining mid-term realizable potential to 2020 in each source of renewable energy. The results show that correlation coefficients between cumulative expenditure and each renewable energy deployment are significantly positive during the implementation period of each deployment program. And photovoltaic energy, bio energy, and wind power energy show high effectiveness indicator.

• 한국IT서비스학회:학술대회논문집
• /
• 2002.11a
• /
• pp.262-268
• /
• 2002

일반산업 분야의 프로젝트에 비해 소프트웨어 개발 분야에서의 프로젝트는 그 자체 특성상 가시적이고 계량적으로 평가하기 어려웠고 이로 인해 그 동안 국내 업계 및 정부기관에서는 프로젝트 규모 및 비용 산정에 있어서 많은 어려움이 있었다. 다행히도 최근 국제적으로 소프트웨어 프로젝트 측정기준으로 자리잡고 있는 기능점수에 관해서 국내 학계 및 업계에서도 관심을 가지게 되었고 관련된 연구결과도 계속 나오고 있다. 또한, 정부기관을 비롯하여 업계에서도 이러한 연구 결과를 기반으로 소프트웨어 개발비, 유지보수 및 재 개발비의 산정 기준으로 기능점수를 활용하려는 시도가 이루어지고 있다. 이러한 기능점수의 산정에 있어서 프로젝트의 주요 개발 요소인 하드웨어 플랫폼, 개발언어 유형, 대상업무 유형, 개발 납기 등에 따라 보정계수가 다르게 적용되고 있다. 그러나 아직 국내에서는 기능점수로 프로젝트 비용을 산정하기 위한 공감대 및 신뢰도에 대한 확산이 안된 상태이고 이에 따른 분쟁의 소지도 여전히 가지고 있다. 이러한 시점에서 본 논문은 ISBSG(International Software Benchmarking Standards Group)에서 제공하는 그 동안 축적된 해외 프로젝트 개발 결과 데이터를 기초로 기능점수와 프로젝트 개발에 투입되는 주요 개발요소간 관련성 및 프로젝트 개발 요소간의 상관관계를 분석 및 검증하여, 프로젝트 내에서의 기능점수와 관련된 개발요소간의 관련 정도에 대한 통계적 근거를 제시하여 향후 기능점수와 관련해서 이와 유사한 국내 프로젝트 수행 시 벤치마킹 자료로 활용하는데 그 목적이 있다.

• Journal of Korean Society of Forest Science
• /
• v.102 no.4
• /
• pp.506-514
• /
• 2013

This study examined the feasibility on the construction of a wood industrialization service center for a wood industry cluster establishment in Jeollanam-do. Construction of the wood industrialization service center is based on a discount rate of 3.5%, an investment period of 4 years, a business operations period of 16 years and an investment cost of 24600 million won; the total amount of the net present value, the cost-benefit ratio and the internal rate of return were assumed to be 2.579 million won, 2.51%, and 10.1%, respectively. In addition, the production inducement coefficient, the induced production effect, the income-induced coefficient, the income inducement effect, the employment inducement coefficient, and the employment inducement effect were estimated 1.4345, 35287 million won, 0.1655, 4000.7 million won, and 0.4665, 1,145 people, in the effects of the wood related industries using the multi-regional input-output model, respectively. Financial independence of operating income to cover its own costs incurred in accordance with the operating project might be practicable.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.54 no.2
• /
• pp.192-197
• /
• 2009

This study was conducted to investigate the effect of site-specific variable fertilization following digital fertility map generated from soil analysis on rice growth and yield. The site-specific application of fertilizer was implemented by using rice transplanter equipped with side dressing applicator and global positioning system (GPS). Coefficient of variation (C.V.) of soil nitrogen content was reduced after the experiment, and spatial variation of semivariogram was reduced. Rice growth from tillering to ripening stage, plant height, tiller and panicle number increased at site-specific variable fertilization treatment, and coefficient variation (C.V.) of each growth characteristics was lower than those of conventional fertilization treatment. As a result, fertility in the rice field was more uniform become of site-specific fertilizer application. Head rice yield of site-specific application plot increased by 9% (i.e., to from 450 kg/10a to 492 kg/10a of the control plot) and its CV was significantly reduced to 3.5 compared to 7.8 of the control plot. In addition, there was no significant difference in amylose, protein contents and whiteness of milled rice, but its CV was reduced.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.8
• /
• pp.542-548
• /
• 2014

Effects of bromide ($Br^-$) and iodide ($I^-$) concentrations, chlorine ($Cl_2$) doses, pH, temperature, ammonia nitrogen concentrations, reaction times and water characteristics on formation of iodinated trihalomethanes (I-THMs) during oxidation of iodide containing water with chlorine were investigated in this study. Results showed that the yields of I-THMs increased with the high bromide and iodide level during chlorination. The elevated pH significantly increased the yields of I-THMs during chlorination. The formation of I-THMs was higher at $20^{\circ}C$ than $4^{\circ}C$, $10^{\circ}C$ and $30^{\circ}C$. In chloramination study, addition of ammonium chloride ($NH_4Cl$) markedly increased the formation of I-THMs. Among the water samples collected from seven water sources including wastewater treatment plant (WWTP) effluent water (EfOM water), prepared humic containing water (HA water) and algal organic matter (AOM) containing water (AOM water), EfOM water generated the highest yields of I-THMs ($12.31{\mu}g/mg$ DOC), followed by HA water ($4.96{\mu}g/mg$ DOC), while AOM water produced the lowest yields of I-THMs ($0.99{\mu}g/mg$ DOC). $SUVA_{254}$ values of EfOM water, HA water and AOM water were $1.38L/mg{\cdot}m$, $4.96L/mg{\cdot}m$ and $0.97L/mg{\cdot}m$, respectively. The I-THMs yields had a low correlation with $SUVA_{254}$ values ($r^2$ = 0.002).

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.23 no.4
• /
• pp.180-188
• /
• 2013

The glass of E-glass fiber composition was fabricated by using refused coal ore which is obtained as by-product from Dogye coal mine in Samcheok. We used silica-alumina refused coal ore which has low carbon content relatively, and the amount of refused coal ore has been changed from 0 to 35 % in batch composition. E-glass was fabricated by the melting of mixed batch materials at $1550^{\circ}C$ for 2 hrs with different refused coal ore composition of 0~35 %. We obtained a transparent and clear glass with high visible light transmittance value of 81~84%, thermal expansion coefficient of $5.39{\sim}5.61{\times}10^{-6}/^{\circ}C$ and softening point of $851{\sim}860^{\circ}C$. The glass fiber samples were also obtained through fiberizing equipment at $1150^{\circ}C$, and tested chemical resistance and tensile strength to evaluate the mechanical property as a reinforced glass fiber of composite material. As the result, we identified the properties of E-glass fiber by using refused coal ore are plenty good enough compare to that of normal E-glass without refused coal ore, and confirmed the possibility of refused coal ore as for the raw material of E-glass fiber.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.2
• /
• pp.634-643
• /
• 2020

In this study, the rheological and tribological properties of urea grease were studied according to the type and amount of polytetrafluoroethylene (PTFE) powders added to the urea grease, which is the most widely used among solid lubricants, to develop an optimal lubrication system. Urea grease was synthesized using 4,4'-methylenebis(phenyl isocyanate)(MDI), oleylamine, and cyclohexylamine, and PTFE powders prepared by dispersion or suspension polymerization process were then added. The basic rheological and tribological properties of the prepared greases were compared. The worked penetration numbers of urea grease decreased with increasing amount of PTFE powders, but both PTFE powders caused no significant changes in heat resistance and copper corrosion resistance. The shear viscosity increased with increasing PTFE powder content, and the dispersion-type PTFE powder was more effective in increasing the viscosity. In the value of the loss coefficient = 1, the shear stress was higher for the grease containing PTFE powders than the non-PTFE added grease, and the dispersion-type PTFE-added grease showed higher viscosity than the suspension-type PTFE-added grease. Finally, urea grease was found to have a low-performance improvement in terms of wear reduction effects by adding PTFE powders, but the load-bearing performance was up to 2.5 times higher for the dispersion-type PTFE and five times higher for the suspension-type PTFE.