• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.193-199
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• 2002

According to the NOx level requirement of annex Vl to IMO(International Maritime Organization) MARPOL 73/78, this regulation shall apply to each diesel engine with a power output of more than 130 ㎾ which is installed on a ship constructed and undergoes a major conversion on or after 1 January 2000. It is inevitable to adopt IMO standard for marine engines. Therefore, most of diesel engines which are being currently built should be tested and surveyed in accordance with the NOx technical code. In this study, various technics of NOx reduction methods were investigated for the diesel engines and the methods of NOx measuring were introduced by the new and simplified field detecting equipment. These results can be utilized for the basic design and developement of diesel engine for NOx reduction.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.39-41
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• 2012

The influence of coal blending methods such as out-furnace (external or pre-mixed) blending and in-furnace (initially non-mixed) blending with different excess oxygen (highest, medium, and lowest stoichiometric conditions) on unburned carbon and NOx emissions of blend combustion in an entrained flow reactor (EFR) has been analyzed, using experimental and numerical approaches for binary coals used by Korean power plants. The results confirm that under the medium condition, contrasting processes such as reactive and un-reactive effects occur with SBRs in the out-furnace blending method. The in-furnace blending method results in an improvement in the efficiency of unburned carbon fractions and a further reduction in the NOx emission. Under the highest condition, the unburned carbon fraction in both the out-furnace and the in-furnace blending methods corresponds with the tendency under the medium condition with contrasting processes of lower magnitude, whereas the NOx emission in the highest condition increases slightly. Under the lowest conditions, the unburned carbon fraction in the out-furnace blending method gradually decreases as SBR decreases, without a competition effect. The reduction of NOx emission under the lowest conditions is more effective than those under other conditions for the two blending methods because of a homogeneous and heterogeneous NOx reduction mechanism.

• 한국연소학회:학술대회논문집
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• 2000.05a
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• pp.26-34
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• 2000

Geometry change of burner nozzle has influence on fuel atomizing and combustion characteristics. NOx reduction technologies can be divided into two method; Before combustion method(NOx treatment of fuel) and After combustion method(NOx treatment of flue gas). In this study, experiments are carried out using difference nozzle and combustion condition change to reduce NOx in heavy oil fired thermal utility boiler. These methods have advantage like easy application and low installation cost. By this method NOx can be reduced by 18% and maintain CO emission level.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.3
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• pp.373-380
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• 2003

According to the NOx regulations of annex Vi to IMO MARPOL 73/78, all diesel engines with a power output of more than 130 kW should be delivered so as to comply with the IMO speed dependent NOx limit. It is inevitable to adopt this regulations for marine engines Therefore, most of diesel engines which are being currently built should be designed and tested in accordance with the NOx technical code In this study, NOx concentrations of 4 type engines were measured with portable NOx measuring system recommended by ISO-8178. As the results NOx concentrations of each engine by variation of engine speed and engine load were visualized Also these results can be utilized for the basic design and development of diesel engine for NOx reduction.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.181-187
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• 2005

The behavior of fox adsorption and desorption of the NOx storage catalyst supported on Ba additive were studied by the TPA/TPD experiments and reactivity tests. Applying the transient responses and NOx TPA/TPD test by CLD were effective methods to analyze the characteristics of the NOx storage catalyst. NOx variation of the NOx storage catalyst in the lean air/fuel conditions according to temperature was dominated by NOx adsorption and desorption rather than catalytic reduction. The presence of reductants in the lean mixture promoted the NOx desorption at the $500^{\circ}C$ higher temperature. The temperatures for maximum NOx conversion with CH4 and $C_3H_6$ as a rich spike reductant appear around $500^{\circ}C\;and\; 400^{\circ}C$ respectively.

• Journal of Mechanical Science and Technology
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• v.18 no.12
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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.

• Journal of the Korean Society of Combustion
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• v.14 no.4
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• pp.25-32
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• 2009

In commercial combustion systems, heavy oil is one of main hydrocarbon fuel because of its economical efficiency. Regarding heavy oil combustion, due to increasing concerns over environmental pollutants such as carbon monoxide, unburned hydrocarbon and nitrogen oxides, development of low pollutant emission methods has become an imminent issue for practical application to numerous combustion devices. Also a great amount of effort has been tried to developed effective methods for practical using of biomass. It is also an important issue to reduce carbon tax. In this paper, an experimental study has been conducted to evaluate the effect of biomass reburning on NOx formation in a heavy oil flamed combustion furnace. Experiments were performed in flames stabilized by a multi-staged burner, which was mounted at the front of the furnace. Experimental tests were conducted using air-carried rice husk powder and LNG as the reburn fuel and heavy oil as the main fuel. The paper reports data on flue gas emissions and temperature distribution in the furnace for several kinds of experimental conditions. NOx concentration in the exhaust has decreased considerably due to effect of reburning. The maximum NOx reduction rate was 62% when the rice husk was used by reburn fuel, however it was 59% when the LNG was used by reburn fuel. The result shows the positive possibility of biomass reburning system for optimal NOx reduction.

• Korean Journal of Exercise Nutrition
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• v.25 no.1
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• pp.16-22
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• 2021

[Purpose] Aerobic exercise training (AT) reverses aging-induced deterioration of arterial stiffness via increased arterial nitric oxide (NO) production. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, was decreased by AT. However, whether AT-induced changes in ADMA levels are related to changes in nitrite/nitrate (NOx) levels remains unclear. Accordingly, we aimed to clarify whether the relationship between plasma ADMA and NOx levels afected the AT-induced reduction of arterial stifness in middle-aged and older adults. [Methods] Thirty-one healthy middle-aged and older male and female subjects (66.4 ± 1.3 years) were randomly divided into two groups: exercise intervention and sedentary controls. Subjects in the training group completed an 8-week AT (60%-70% peak oxygen uptake [${\dot{V}}O_{2peak}$] for 45 min, 3 days/week). [Results] AT signifcantly increased ${\dot{V}}O_{2peak}$ (P < 0.05) and decreased carotid β-stifness (P < 0.01). Moreover, plasma ADMA levels were significantly decreased while plasma NOx levels and NOx/ADMA ratio were significantly increased by AT (P < 0.01). Additionally, no sex diferences in AT-induced changes of circulating ADMA and NOx levels, NOx/ADMA ratio, and carotid β-stifness were observed. Furthermore, the AT-induced increase in circulating ADMA levels was negatively correlated with an increase in circulating NOx levels (r = -0.414, P < 0.05), and the AT-induced increase in NOx/ADMA ratio was negatively correlated with a decrease in carotid β-stifness (r = -0.514, P < 0.01). [Conclusion] These results suggest that the increase in circulating NOx with reduction of ADMA elicited by AT is associated with a decrease in arterial stiffness regardless of sex in middle-aged and older adults.

• 한국연소학회:학술대회논문집
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• 2001.11a
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• pp.1-7
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• 2001

FGR is one of the most widely used methods of NOx reduction in the combustion process. It was investigated the effect of FGR, excess air ratio, peak temperature and firing rate on NOx emission in this study. 100kW burner and LNG were adopted in this experiment. NOx emission was notably decreased with the increase of FGR, however CO emission was also drastically increased in the 25% FGR. And excess air ratio, peak temperature and firing rate did not affect the NOx emission appreciably in the normal operating condition.

• International Journal of Highway Engineering
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• v.19 no.1
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• pp.53-62
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• 2017

PURPOSES : This research was a fundamental study on the application of an integral $TiO_2$ solution to asphalt concrete pavement. The integral $TiO_2$ solution was produced in pilot production equipment; application of the integral $TiO_2$ solution to asphalt pavement was conducted to examine the pollution-reducing capability of photocatalytic compounds such as $TiO_2$. The photocatalytic $TiO_2$ reacted with air pollutants, converting them into small amounts of relatively benign molecules. METHODS : In this study, laboratory experiments were conducted using five various testing methods. Tensile strength ratio (TSR) and British pendulum test (BPT) were conducted in order to evaluate the properties of asphalt pavement subsequent to the integral $TiO_2$ solution coating. In addition, methylene blue testing, a measurement of nitrate on the coated pavement, and nitrogen oxide (NOx) reduction testing were conducted in order to evaluate photocatalytic reaction. Lastly, a UV-A lamp was used as a light source for photocatalytic reactions. RESULTS : Test results indicated no change in the properties of asphalt pavement following the integral $TiO_2$ solution coating. In order to evaluate the performance of asphalt pavement as a function of $TiO_2$, the moisture susceptibility and skid resistance were investigated. The moisture susceptibility and skid resistance satisfied there quirements related to pavement quality and safety specification. Furthermore, the effects of reduction of air pollution were significantly improved as determined via the methylene blue test and NOx reduction test. The $TiO_2$-paved asphalt specimen exhibited approximately 43% reduction of NOx. CONCLUSIONS : This study has suggested that applying $TiO_2$ rarely impacts asphalt pavement performance measures such as moisture susceptibility and skid resistance, and that its application may be a better means of reducing air pollution. Further studies, such as proper $TiO_2$ dosage rates and compatibility with various pavement types, are required to broaden and generalize its application.