• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.57-63
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• 2004

In this paper, the NOx emission and the reduction technologies of NOx emission for domestic marine diesel engine were investigated. At first, the present production status of domestic marine diesel engines was investigated. In the next, the NOx emission of domestic marine diesel engines was investigated. Finally, the present status of a reduction technologies of NOx emission was investigated. From this investigation, It could be founded that the domestic marine diesel engines satisfied the IMO current NOx regulations, however the higher technologies must be studied to prepare the more severe IMO regulations of the near future.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.3
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• pp.196-200
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• 2019

In this study, photoluminescence (PL) analysis was performed to evaluate the optical properties of commercial ZnO substrates. Particular attention was paid to the bound exciton (BX) luminescence, which is usually the strongest emission intensity of commercial substrates. At 15 K, PL analysis revealed that the BX peak due to donor-type impurities (donor-bound-exciton; DX) dominated, while two-electron satellite (TES) emission, donor-accepter pair (DAP) emission, and LO-phonon replica emission were also observed. The impurity concentration of the ZnO substrate was determined to be $10^{15}$ to $10^{16}/cm^3$ by examination of the temperature variation of DAP, while the half width and intensity change of the luminescence revealed that the temperature change of BX can be interpreted almost the same as the analysis of free-exciton emission.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.12 no.1
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• pp.1-6
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• 1976

To investigate the relation of $NO_x$ emission and consumption rate in a direct injection diesel engine with a multihole nozzle under same fuel consumption and rpm, a naphthyl ethylenediaming method on NO, emission and Tektronix oscilloscop on the indicator diagrams have been used. Comparisons of the $NO_x$ emission and fuel consumption rate made on various conditions have led to the fllowing results. 1. The higher the injection pressure in the later injection time the lower $NO_x$ emission and the fuel consumption rate have been attained. 2. By the change of nozzle hole diameter under the same injection pressure, the $NO_x$ emission was much more lowered in the small diameter than large one, but fuel consumption rate was in inverse proption to the $NO_x$ emission. 3. The effect of injection spray angle, $\frac{1_n}{d_n}$ on $NO_x$ emission, fuel consumption rate under same injection time and injection pressure was neglectable.

• Ocean and Polar Research
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• v.39 no.3
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• pp.195-203
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• 2017

The purpose of this paper is to estimate the optimal $CO_2$ emission in the maximum economic yield (MEY), maximum sustainable yield (MSY), and open access (OA) using a bioeconomic model. The results are as follows; in the case of $E_{MEY}$, $E_{MSY}$, and $E_{OA}$ levels, $CO_2$ emissions are estimated at $150,704,746CO_2/kg$, $352,211,193CO_2/kg$, and $301,409,492CO_2/kg$ respectively. We show that the $E_{MEY}$ is more efficient than the other levels. That is, the level of $E_{MEY}$ signifies the optimal economic fishing usage as the most economically efficient usage for large purse seine fishery catching mackerel species. The emission of $CO_2$ in $E_{MEY}$ is the lowest level. Also, the impacts of climate changes such as ocean temperature increase, ocean acidification, and the combined impact thereof show that the biomass of mackerel decreases.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.92-92
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• 2017

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.4
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• pp.174-179
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• 2004

Domestic marine diesel engine makers reduce the NOx emission mostly by applying low NOx fuel nozzle and injection timing retard. However, it is necessary to develop high efficient technology (EGR, DWI and SCR, etc.) to reduce NOx emission in order to prepare for the further reinforcement of the NOx emission limit. Also, in the near future, IMO will restrict additively THC, PM and CO with NOx. Therefore, domestic engine makers have to prepare for it and the relevant government ministries should give a sufficient support to these technology research and establish or amend the relevant law, which should include the excursion riverboat.

• Journal of Ocean Engineering and Technology
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• v.35 no.6
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• pp.393-402
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• 2021

As greenhouse gas emissions from maritime transport are increasing, the International Maritime Organization is continuously working to strengthen emission regulations. Liquefied natural gas (LNG) fuel is less advantageous as a point of CO₂ reduction due to the methane leakage that occurs during the bunkering and operation of marine engines. In this study, greenhouse gas emissions from an LNG-fueled ship were analyzed from the perspective of the life cycle. The amount ofmethane emission during the bunkering and operation procedures with various boil-off gas (BOG) treatment methods and gas engine specifications was analyzed by dynamic simulation. The results were also compared with those of other liquid fuel engines. As a result, small LNG-fueled ships without a BOG treatment facility emitted 32% more greenhouse gas than ships utilizing marine gas oil or heavy fuel oil. To achieve a greenhouse gas reduction via a BOG treatment method, a gas combustion unit or re-liquefaction system must be mounted, which results in a greenhouse gas reduction effect of about 25% and 30%. As a result of comparing the amount of greenhouse gas generated according to the BOG treatment method used with each tank size from the perspective of the operating cycle with the amounts from using existing marine fuels, the BOG treatment method showed superior effects of greenhouse gas reduction.

• Journal of Environmental Science International
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• v.11 no.8
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• pp.773-781
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• 2002

The natural carbon cycle has been perturbed since the mid-19th century by anthropogenic CO$_2$emissions from fossil fuel combustion and deforestation due to population growth and industrialization. The current study simulated the global carbon cycle for the past 42 years using an eight-box carbon cycle model. The results showed that since the terrestrial biospheric carbon sink was roughly offset by the deforestation source, the fossil fuel emission source was partitioned between the atmospheric and oceanic sinks. However, the partitioning ratio between the atmosphere and the ocean exhibited a change, that is, the carbon accumulation rate was faster in the atmosphere than in the ocean, due to a decrease in the so-called ocean buffering capacity. It was found that the ocean buffering capacity to take up excess CO$_2$decreased by 50% in terms of the buffer factor over the past 42 years. Accordingly, these results indicate that if the current CO$_2$emission trend continues, the future rate of increase in the atmospheric CO$_2$concentration will accelerate.

• Journal of Ocean Engineering and Technology
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• v.14 no.3
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• pp.84-89
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• 2000

The purpose of this study is to investigate the combustion emission characteristics by the effect of secondary air injection and variation of the excess air ratio in combustion field of model gas turbine combustor. For this purpose, mean temperature, CO, $CO_2$, $O_2$ and HC concentrations were measured by changing excess air ratio and secondary air injection. As a result of this study, mean temperature was decreased and CO, HC emission increased by increasing the excess air ratio of secondary air. Therefore, this results showed the secondary air injection effected strongly on the flame structure and combustion emission characteristics.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.171-176
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• 2000

This purpose of this study is to investigate the combustion emission characteristics on the effect of secondary air injection in combustion field of model gas turbine combustor changing excess air ratio. For this purpose, meantemperature, CO, CO2, O2 and HC concentration were measured by changing excess air ratio and secondary air injection. As a result of this study, meantemperature, CO2 emission was decreased and CO emission increased by increasing the excess air ratio of secondary air. therefore, This paper showed the effect of Secondary air injection on flame structure, combustion emission characteristics.