• 자원ㆍ환경경제연구
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• 제15권3호
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• pp.425-450
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• 2006

산업부문은 생산 활동을 담당하는 특성 때문에 많은 에너지를 소비하고 많은 $CO_2$를 배출한다. 산업부문 중에서 에너지다소비산업이라고 일컬어지는 산업들은 다른 산업에 비해서 에너지소비가 많고 $CO_2$ 배출을 많이 하므로 관련정책의 목표대상으로서 우선적으로 거론된다. 그러나 해당 산업의 생산액과 $CO_2$ 배출량을 사용하는 환경원단위는 해당 산업만의 환경오염물질 배출의 정도를 측정하기에는 적합하지만, 산업들이 유기적으로 연결되어 서로 생산품을 수요하고 공급하고 있는 점을 고려한다면 환경원단위를 확대시킨, 그리고 산업 전체를 고려하는 지표로 해당 산업의 환경물질의 배출 정도를 평가해야 한다. 이에 본 논문에서는 우리나라의 환경산업연관표 2000을 작성하고, 에너지다소비산업 외에 전 산업을 대상으로 하여 산출액기준 및 열량기준의 환경원단위와, 이를 보다 확대하고 산업의 유기적 관계까지를 모두 고려하는 유발 $CO_2$ 발생량을 추정하여 우리나라의 경제주체간 및 산업간의 상품생산과 흐름에 수반되는 에너지소비와 환경오염물질의 흐름을 분석하였다. 분석결과에 따르면 산출액기준 및 열량기준의 환경원단위가 상대적으로 높은 산업들의 유발 $CO_2$ 발생량은 크다. 이 산업들은 직접적으로 발생시키는 $CO_2$가 많은 산업들이며, 환경부하가 큰 재화나 서비스를 생산한다. 그러므로 이 산업들을 대상으로 환경원단위 저감을 유도한다면 $CO_2$ 발생량을 감소시킬 수 있다. 그러나 환경원단위가 낮은 산업의 생산 시에 환경원단위가 높은 산업들의 생산품이 투입재로 사용된다면 그 산업의 유발 $CO_2$ 발생량은 커지고 경제 전체의 환경부하를 크게 만든다. 따라서 산출액기준의 환경원단위가 높은 산업들만을 중심으로 하여 환경원단위를 저하시키는 것 외에, 낮은 환경원단위를 갖는 산업들의 환경원단위도 지속적으로 감소시켜 다른 산업에 대한 연관을 통한 유발 $CO_2$ 발생량을 감소시켜야 한다. 이는 모든 산업에 대한 지속적인 환경원단위 저감이 경제 전체를 기준으로 더 큰 $CO_2$ 발생량 저감을 유도하는 것을 의미한다.

• 한국환경농학회지
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• 제30권2호
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• pp.99-104
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• 2011

BACKGROUND: Application of urea may increase $CO_2$ emission from soils due both to $CO_2$ generation from urea hydrolysis and fertilizer-induced decomposition of soil organic carbon (SOC). The objective of this study was to investigate the effects of increasing urea application on $CO_2$ emission from soil and mineralization kinetics of indigenous SOC. METHODS AND RESULTS: Emission of $CO_2$ from a soil amended with four different rates (0, 175, 350, and 700 mg N/kg soil) of urea was investigated in a laboratory incubation experiment for 110 days. Cumulative $CO_2$ emission ($C_{cum}$) was linearly increased with urea application rate due primarily to the contribution of urea-C through hydrolysis to total $CO_2$ emission. First-order kinetics parameters ($C_0$, mineralizable SOC pool size; k, mineralization rate) became greater with increasing urea application rate; $C_0$ increased from 665.1 to 780.3 mg C/kg and k from 0.024 to 0.069 $day^{-1}$, determinately showing fertilizer-induced SOC mineralization. The relationship of $C_0$ (non-linear) and k (linear) with urea-N application rate revealed different responses of $C_0$ and k to increasing rate of fertilizer N. CONCLUSION(s): The relationship of mineralizable SOC pool size and mineralization rate with urea-N application rate suggested that increasing N fertilization may accelerate decomposition of readily decomposable SOC; however, it may not always stimulate decomposition of non-readily decomposable SOC that is protected from microbial decomposition.

• 한국자동차공학회논문집
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• 제21권5호
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• pp.151-156
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• 2013

The experiment was done on cars travelling at the speeds of 20km/h, 60km/h and 100km/h using the performance testing mode for chassis dynamometer. In this experiment, the relativity between the secondary waveform coming from ignition coil and exhaust emissions were measured in case of cars with failures, in oxygen sensor, spark plugs. The following results obtained by analysis of the relativity between the secondary waveform and exhaust emissions. 1) When the oxygen sensor is failure, the average value of CO emission measured was 6.8 times higher than the standard CO emission value and the average value of HC emission measured was 2.3 times higher than the standard emission level. 2) When engine parts are in failure, more fuel enters the cylinder due to longer opening duration of injector, and it tended to make CO and HC emission values increase. 3) Combustion duration, the shape of flame propagation during spark line, and the size of the discharge-induced energy were the three main elements that directly cause variations in CO and HC emission values.

• Journal of Advanced Marine Engineering and Technology
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• 제31권3호
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• pp.282-292
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• 2007

The present paper describes the results of high speed photography, acoustic emission (AE) detection and plasma light emission (LE) measurement during $CO_2$ laser welding of 304 stainless steel in different processing conditions. Video images with high spatial and temporal resolution allowed to observe the melt dynamics and keyhole evolution. The existence of keyhole was confirmed by the slag motion on the weld pool. The characteristic frequencies of flow instability and keyhole fluctuations at different welding speed were measured and compared with the results of Fourier analyses of temporal AE and LE spectra. The experimental results were compared with the newly developed numerical model of keyhole dynamics. The model is based on the assumption that the propagation of front part of keyhole into material is due to the melt ejection driven by laser induced surface evaporation. The calculations predict that a high speed melt flow is induced at the front part of keyhole when the sample travel speed exceeds several 10 mm/s. The numerical analysis also shows the hump formation on the front keyhole wall surface. Experimentally observed melt behavior and transformation of the AE and LE spectra with variation of welding speed are qualitatively in good agreement with the model predictions.

• Journal of Mechanical Science and Technology
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• 제18권12호
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• pp.2303-2309
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• 2004

Flue gas recirculation (FGR) is a method widely adopted to control NOx in combustion system. The recirculated flue gas decreases flame temperature and reaction rate, resulting in the decrease in thermal NO production. Recently, it has been demonstrated that the recirculated flue gas in fuel stream, that is, the fuel induced recirculation (FIR), could enhance a much improved reduction in NOx per unit mass of recirculated gas, as compared to the conventional FGR in air. In the present study, the effect of FGR/FIR methods on NOx reduction in turbulent swirl flames by using N$_2$ and CO$_2$ as diluent gases to simulate flue gases. Results show that CO$_2$ dilution is more effective in NO reduction because of large temperature drop due to the larger specific heat of CO$_2$ compared to N$_2$ and FIR is more effective to reduce NO emission than FGR when the same recirculation ratio of dilution gas is used.

• 대한화학회지
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• 제40권4호
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• pp.235-242
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• 1996

기체 크로마토그래피와 쉽게 연결할 수 있는 Surfatron형의 MIP(Microwave Induced Plasma)용 cavity를 제작하고 헬륨, 아르곤, 질소 등을 플라스마 가스로 사용하여 플라스마를 생성시키고 스펙트럼을 비교하였다. 또한 헬륨과 아르곤, 질소에 미량의 CO2를 혼합하여 각 기체의 스펙트럼을 비교 분석하였으며, 제작한 MIP cavity가 질량분석기와 연결되었을 때 분자이온을 생성시킬 수 있는 이온원으로서의 가능성을 연구하였다. 헬륨과 아르곤 MIP는 높은 준안정 준위의 에너지를 가지기 때문에 분자들이 거의 다 깨어지므로 분자상태로 시료기체의 검출은 거의 불가능하였다. 그러나 질소는 다른 비활성기체에 비하여 낮은 준안정 준위의 어네지를 가지므로 검출하려는 기체성분이 상당부분 분자상태로 존재함을 알 수 있었다.

• 자원ㆍ환경경제연구
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• 제20권1호
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• pp.1-31
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• 2011

본 논문에서는 우리나라의 2005년 환경산업연관표(76개의 내생부문, 21개의 에너지원)를 작성하고, 중간수요부문과 최종수요부문을 대상으로 중간투입액기준의 $CO_2$ 원단위, 열량기준의 $CO_2$ 원단위, 유발 $CO_2$ 발생량을 추정하고, 경제주체간 및 산업간의 상품생산과 흐름에 수반되는 에너지소비와 $CO_2$의 흐름을 분석하였다. $CO_2$ 원단위의 비교에 따르면 최종수요부문이 더 높은 열량을 갖는 에너지원을 사용하며, 중간수요부문이 환경친화 정도가 상대적으로 낮은 에너지원을 사용하여 동일 열량에 대해서 $CO_2$를 더 배출시키고 있다. 유발 $CO_2$ 발생량이 높은 산업은 화력발전($32.587CO_2-g$/원), 시멘트($10.370CO_2-g$/원), 도로운송($7.255CO_2-g$/원), 코크스 및 기타석탄제품($5.791CO_2-g$/원), 증기 온수공급업 수도($4.575CO_2-g$/원)이다. 높은 $CO_2$ 원단위의 산업들의 $CO_2$ 원단위를 저감시키는 것은 해당산업의 환경친화성을 높이는 것과 함께, 경제 전체의 환경친화성을 높인다. 더하여 선철 및 조강처럼 낮은 $CO_2$ 원단위를 갖지만 높은 영향력계수와 감응도계수를 갖는 산업의 $CO_2$ 원단위도 낮추어야 한다. 이 산업들은 다른 산업에게, 그리고 다른 산업으로부터 상대적으로 큰 영향을 받기 때문에 $CO_2$ 원단위가 낮더라도 환경친화성을 갖추어야 유발 $CO_2$ 발생량을 낮출 수 있다.

• Journal of Mechanical Science and Technology
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• 제19권6호
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• pp.1358-1365
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• 2005

Flue gas recirculation (FGR) is widely adopted to control NO emission in combustion systems. Recirculated flue gas decreases flame temperature and reaction rate, resulting in the decrease in thermal NO production. Recently, it has been demonstrated that the recirculated flue gas in fuel stream, that is, the fuel induced recirculation (FIR), could enhance much improved reduction in NO per unit mass of recirculated gas, as compared to conventional FGR in air. In the present study, the effect of dilution methods in air and fuel sides on NO reduction has been investigated numerically by using $N_2$ and $CO_2$ as diluent gases to simulate flue gases. Counterflow diffusion flames were studied in conjunction with the laminar flamelet model of turbulent flames. Results showed that $CO_2$ dilution was more effective in NO reduction because of large temperature drop due to the larger specific heat of $CO_2$ compared to $N_2$. Fuel dilution was more effective in reducing NO emission than air dilution when the same recirculation ratio of dilution gas was used by the increase in the nozzle exit velocity, thereby the stretch rate, with dilution gas added to fuel side.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.3-8
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• 1998

Using GIS and socio-economical data the relationship between human activities and global environmental change Is Analysed from the view point of food productivity and CO2 emission. Under the assumption that the population problem, the food problem and global warming due to energy consumption can be stabilized through managing land use, impacts of human activities such as consumption of food, energy and timber on global environment changes, and global population capacity are Analysed using developed system dynamics model in the research. In the model the world is divided into two groups: OECD countries and the others. Used global land use data set Is land cover map derived from satellite data, and potential distribution of arable land is estimated by the method of Clamor and Solomon which takes into consideration spatial distribution of climate data such as precipitation and evapotranspiration. In addition, impacts of CO2 emission from human activities on food production through global warming are included in the model as a feedback. The results of the analysis for BaU scenario and Toronto Conference scenario are similar to the results of existing models. From the result of this study, the human habitability in 2020 is 8 billion people, and CO2 emission in 2020 based on BaU Scenario and on Toronto Scenario is 1.7 and 1.2 times more than the 1986's respectively. Improving spatial resolution of the model by using global data to distribute the environmental variables and sauce-economical indices is left for further studies.

• Journal of Mechanical Science and Technology
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• 제17권8호
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• pp.1203-1210
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• 2003

Emission of ultrasonic vibration to turbulent flow promotes the turbulence generation due to the resonantly oscillating pressure field and thereby induced cavitation. In addition, ultrasonic vibration is well transmitted through water and not dissipated easily so that the micro-bubbles involved in the fluid induce the gaseous cavitation if the bubbles are resonated with the ultrasonic field. In the present study, we found through LDV measurement that the gaseous cavitation induced by ultrasonic vibration to CO$_2$saturated water flow in the rectangular cross-sectioned straight duct enhances turbulence much more than the case of non-ultrasonic or normal ultrasonic conditions without gaseous cavitation. We also found that the fluctuating velocity component induced by emitting the ultrasonic vibration in normal direction of a rectangular channel flow can be redistributed to stream-wise component by the agitation of gaseous cavitation.