• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2354-2359
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• 2007

Influence of changing combustor pressure on flame stabilization and emission index in the swirl-stabilized flame was investigated. The combustor pressure was controlled by suction fan at combustor exit. Pressure index ($P^{\ast}$=Pabs/Patm), where Pabs and Patm indicated the absolute pressure and atmosphere pressure, respectively, was controlled in the range of 0.7${\sim}$1.3 for each equivalence ratio conditions. The flammable limits of swirl flames were largely influenced by changing combustor pressure and they showed similar tendency with laminar flames. NOx emission index decreased with decreasing pressure index for overall equivalence ratio conditions. R.m.s. of pressure fluctuations is increased with decreasing combustor pressure. This flame fluctuation caused incomplete combustion, hence CO emission index increased. These oscillating flames were measured by simultaneous $CH^{\ast}$ chemiluminescence time-series visualization and pressure fluctuation measurement.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2007년도 제34회 KOSCO SYMPOSIUM 논문집
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• pp.133-138
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• 2007

Influence of changing combustor pressure on flame stabilization and emission index in the swirl-stabilized flame was investigated The combustor pressure was controlled by suction fan at combustor exit. Pressure index ($P^{\ast}=P_{abs}/P_{atm}$), where $P_{abs}$ and $P_{atm}$ indicated the absolute pressure and atmosphere pressure, respectively, was controlled in the range of $0.7{\sim}1.3$ for each equivalence ratio conditions. The flammable limits of swirl flames were largely influenced by changing combustor pressure and they showed similar tendency with laminar flames. $NO_x$ emission index decreased with decreasing pressure index for overall equivalence ratio conditions. R.m.s. of pressure fluctuations is increased with decreasing combustor pressure. This flame fluctuation caused incomplete combustion , hence CO emission index increased. These oscillating flames were measured by simultaneous $CH{\ast}$ chemiluminescence time-series visualization and pressure fluctuation measurement.

• 산경연구논집
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• 제10권2호
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• pp.7-15
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• 2019

Purpose - The industrial structure upgrading can play an important role in promoting the carbon emission efficiency. Thus, this paper attempts to study the impact of industrial structure upgrading on carbon emission efficiency in order to reduce carbon emissions. Research design, data, and methodology - This paper selects panel data of 30 provinces and municipalities (autonomous regions) in China from 2001 to 2016, and divides them into three regions. The Moore index is used to measure the industrial structure upgrading, the non-radial SBM model based on undesired output is used to measure the slack variable to calculate the total factor carbon emission efficiency. Finally the impact of industrial structure upgrading on the carbon emission efficiency are analyzed. Results - It is found that the Moore index and the carbon emission efficiency in the eastern region is the highest in the three regions. Conclusions - The influence of various influencing factors on carbon emission efficiency is different between regions. The Moore index has a positive effect on the carbon emission efficiency in the eastern region, and has a negative influence coefficient on the central region. The effect on the western region is not obvious.

• 한국축산시설환경학회지
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• 제4권2호
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• pp.183-191
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• 1998

This study was carried out to elucidate the correlation between Germination Index(G.I.) and CO2 emission for evaluation of the maturity of compost products. 13 compost samples was used for this experiment. The G.I. test was carried out on the basis of T-N 200ppm. As a result of this research, we found that CO2 emission method was good simple indicator for evaluation of maturity of compost materials, in spite of G.I. The obtain results are summarized as follows ; 1. The correlation value between the G.I. and the CO2 emission was R2 = 0.776. 2. The correlation value between EC(Electric Conductivity) and G.I. was R2 =0.7. 3. The equation calculated from G.I. and CO2 emission was G.I. = -16.7(InCO2) - 6.87. 4. From these results, we found the possibility of estimation for the value of G.I.(T-N 200ppm) from CO2 emission volume under specific condition.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제33회 KOSCO SYMPOSIUM 논문집
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• pp.128-133
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• 2006

Influence of changing combustor pressure on flame stabilization and nitrogen oxide (NOx) emission in the swirl-stabilized flame with secondary fuel injection was investigated. The combustor pressure was controlled by suction at combustor exit. Pressure index ($P{\ast}=P_{abs}/P_{atm}$), where $P_{abs}$ and $P_{atm}$ indicated the absolute pressure and atmosphere pressure, was controlled in the range of $0.7{\sim}1.3$ for each equivalence ratio conditions. The flammable limits of swirl flames were largely influenced by changing combustor pressure and they showed different tendency compared with laminar flames. Emission index showed maximum value near atmospheric condition and decreased with decreasing pressure index for overall equivalence ratio conditions. R.m.s of pressure fluctuations also showed similar tendency with nitric oxide emission. By injecting secondary fuel into flame zone, the flammable limits were extended significantly. Emission index of nitric oxide and r.m.s. of pressure fluctuations were also controlled by injecting secondary fuel. The swirl flames were somewhat lifted by secondary fuel with high momentum, hence low nitric oxide emission. This NOx reduction technology is applicable to industrial furnaces and air conditioning system by adopting secondary fuel injection.

• 한국기후변화학회지
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• 제9권4호
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• pp.407-421
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• 2018

In this paper, I analyze the GHG (greenhouse gas) emission factor of the domestic railway transportation sector using the LMDI (Log Mean Divisia Index) methodology. These GHG factors are the emission factor effect, energy intensity effect, transportation intensity effect, and economic activity effect. The analysis period was from 2011 to 2016, and the analysis objects were an intercity railway, wide area railway, and urban railway. The results show that the GHG emission of railway transportation sector decreased during these 6 years. The factors decreasing the GHG emission are the emission factor effect, energy intensity effect, and transportation intensity effect, while the factor increasing the GHG emission is the economic activity effect.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.569-572
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• 2006

In present study, the influence of changing combustor pressure on flame stabilization and nitrogen oxide (NOX) emission in the swirl flame with secondary fuel injection was investigated. The combustor pressure was controlled by suction at combustor exit. Pressure index ($P^*=Pabs/Patm$), where Pabs and Patm indicated the absolute pressure and atmosphere pressure, was controlled in the range of 0.7~1.15 for each equivalence ratio conditions. It could be observed that flame stable region became narrower with decreasing equivalence ratio and pressure index. In this combustion system, stable flames were formed until $P^*=\;0.7$. Emission index decreased with decreasing pressure index for overall equivalence ratio conditions and NOx reduction rates were almost identical for $P^*<1$ regardless of equivalence ratio though EINOx values showed different level with change of equivalence ratio for $P^*{\geq}1$. It is also observed that EINOx decreased with increasing secondary fuel injection ratio. Emission index of nitric oxide was controllable by adjusting the changing combustor pressure and injecting secondary fuel and this NOx reduction technology is applicable to industrial furnaces and air conditioning system.

• Geomechanics and Engineering
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• 제37권2호
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• pp.149-166
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• 2024

The acoustic emission (AE) technique is utilized to estimate the rock failure status in underground spaces. Understanding the AE characteristics under loading conditions is essential to ensure the reliability of AE monitoring. The AE characteristics depend on the material properties (p-wave velocity, density, UCS, and Young's modulus) and damage stages (stress ratio) of the target rock mass. In this study, two groups of granite specimens (based on the p-wave velocity regime) were prepared to explore the effect of material properties on AE characteristics. Uniaxial compressive loading tests with an AE measurement system were performed to investigate the effect of the rock properties using AE indices (count index, energy index, and amplitude index). The test results were analyzed according to three damage stages classified by the stress ratio of the specimens. Count index was determined to be the most suitable AE index for evaluating rock mass stability.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제21회 KOSCO SYMPOSIUM 논문집
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• pp.67-76
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• 2000

Experimental and numerical investigation on NOx emission characteristics with equivalence ratios, fuel flow rates and nozzle diameters were studied in CH4 Jet flames. Emission indices of NOx were measured by chemiluminescent method with carbon converter. Numerical analyses were carried out with GRl-2.11 mechanism that includes C2-chemistry and all of NO reaction mechanisims. The roles of thermal NO and prompt NO mechanism on each flame's NOx emission index were investigated. The results of this study show that the numerical results represent well the trends of ElNOx experimentally observed. The numerical analyses clarified the trends of EINOx with equivalence ratios, fuel flow rates and nozzle diameters.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제20회 KOSCO SYMPOSIUM 논문집
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• pp.35-44
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• 2000

It was numerically studied that NOx emission characteristics of confined $CH_{4}$ jet flames with the variation of the diameter of inner fuel nozzle, the flow rate of $CH_{4}$ and equivalence ratio. Parabolic type equations were adopted in the calculation and GRI-2.1I mechanism was used for the chemical reaction. NOx emission index (EINOx) was introduced to evaluate NOx emission quantitatively in parametrically varied flames and the contribution of Thermal and Prompt NO mechanism was discussed. The results showed that Total EINOx varied sensitively with the variation of the flow rate of$CH_{4}$ but it was not sensitive to the variation of the diameter of inner fuel nozzle. Thermal EINOx showed the similar tendency to total EINOx and Prompt EINOx showed insensitivity to the variation of the diameter of inner fuel nozzle and the flow rate of $CH_{4}$.