• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1213-1219
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• 2008

The deterioration analysis of electric systems in diesel electric locomotives, which were used for over 30 years, was performed to understand current wear and safety information. The electric systems include electric generation, traction motors, control units, high-voltage cables, and wires. In this investigation, various types of performance testing, such as insulation resistance measurement and degradation tests, were conducted to assess the degree of current deterioration. Moreover, an infrared camera was employed to verify abnormal heating in cables and wires. In this paper, the new techniques for evaluation of deterioration in electric systems have been introduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.474-481
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• 2018

The policy-making and technological development of eco-friendly automobiles designed to increase their supply is ongoing, but the internal combustion engine still accounts for approximately 95% of automobiles in use. To meet the stricter emission regulations of internal combustion engines based on fossil fuels, the proportion of after-treatments for vehicles and (ocean going) vessels is increasing continuously. As diesel engines have high power and good fuel economy in addition to less CO2 emissions, their market share is increasing not only in commercial vehicles, but also in passenger cars. Because of the characteristics of the diesel combustion, however, NOx is generated in localized high-temperature combustion regions, and particulates are formed in the zones of diffusion combustion. LNT and urea-SCR catalysts have been developed for the after-treatment of exhaust gas to reduce NOx in diesel vehicles. This study examined the effect of a containing promoter on SCR catalysts to cope with the severe exhaust gas regulation. The de-NOx performance of the Mn-SCR catalyst was the best, and the de-NOx performance was improved as the ion exchange rate between Mn ion and Zeolyst was good and the activation energy was low. The de-NOx performance of the 7Cu-15Ba/78Zeoyst catalyst was 32% at $200^{\circ}C$ and 30% at $500^{\circ}C$, and showed the highest performance. The NOx storage material of BaO loaded as a promoter was well dispersed in the Cu-SCR catalyst and the additional de-NOx performance of BaO was affected by the reduction reaction of the Cu-SCR catalyst. Among the three catalysts, the 7Cu-15Ba/Zeolyst SCR catalyst was resistant to thermal degradation. The same type of CuO due to thermal degradation migrates and agglomerates because BaO reduces the agglomeration of the main catalyst CuO particles.

• Clean Technology
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• v.2 no.1
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• pp.53-59
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• 1996

For the development of biocatalysts and processes for microbial desulfurization of petroleum, more than 60 microbial strains capable of DBT(Dibenzothiophene) degradation were isolated from oil-polluted soils through 3 months of continuous and enrichment cultures. Among them, A23-3 strain could grow on DBT as the only sulfur source, while hexadecane was not utilized as a carbon source. The rate of desulfurization by A23-3 in a DBT-glucose medium was satisfactory. The addition of yeast extract or trace metal solution accelerated the rate of desulfurization about 4.5~6.5 times. In case of actual diesel oil treatment, the specific rate of DBT degradation was $0.045g-DBT\;per\;g-cell{\cdot}hour$. A number of aromatic compounds heavier than $C_{14}$ in diesel oil were also degraded by A23-3. A23-3 strain was evaluated as a good catalyst for the production of low-sulfur, low-aromatic clean diesel oil.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.265-272
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• 2017

Some bacteria with different mechanisms for hydrocarbon degradation were isolated from oil-contaminated soils in Korea. Isolate Acinetobacter calcoaceticus SL1 showed biosurfactant- producing activity in oil-spreading test, and it exhibited a good emulsifying activity of 43.6 and 54.5% for diesel oil and n-hexane, respectively. It also has high cell surface hydrophobicity which can make it easily attaches to hydrocarbons and degrade them. It degraded 100% of 1,000 mg/L of n-octadecane and naphthalene, respectively in 3 days, 72.3% of 1,000 mg/L diesel oil in 7 days and 78.0% of 10,000 mg/L diesel oil in oil-contaminated soil during 28 days. Isolated strains Bacillus amyloliquefaciens S10 and B. subtilis GO9 can produce biosurfactant and formed 6.34 and 2.5 cm diameter of clear zones, respectively in oil-spreading test. Surface tension of their culture supernatant reduced from 74.6 to 34.4 and 33.3 mN/m, respectively during incubation, and critical micelle concentrations of culture supernatants were 2.0 and 5.9%, respectively. Consortium of A. calcoaceticus SL1 and B. amyloliquefaciens S10 degraded 77.8% of 10,000 mg/L diesel oil in 3 days, which indicated more efficient oil degradation than that by A. calcoaceticus SL1 alone. If these bacteria were applied together as a consortium to oil-contaminated sites, they may show a high removal rate of petroleum hydrocarbons.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.155-161
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• 2000

To improve the vehicle fuel economy, various technologies such as improvement of power train efficiency, use of light weight material, improvement of aerodynamic design, have been studied. One of the possible way to improve the vehicle fuel economy is to reduce the engine friction loss by improving the engine oil characteristics. In the present paper, it was examined the effect of the engine oil viscosity and the addition of friction modifier to engine oil on vehicle fuel economy improvements. Moreover, the effect of engine oil degradation on vehicle fuel economy was examined with two gasoline vehicles and one diesel vehicle by using the fuel economy test facility.

• New & Renewable Energy
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• v.5 no.4
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• pp.52-58
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• 2009

Upgrading of pyrolysis wax oil using HZSM-5 catalyst has been conducted in a continuous fixed bed reactor at $450^{\circ}C$, 1hour, LHSV 3.5/h. The catalytic degradation was studied with a function of catalyst amount and reaction temperature. The raw pyrolysis wax oil shows relatively high boiling point distribution ranging from around $300^{\circ}C$ to $550^{\circ}C$, which has considerably higher boiling point distribution than that of commercial diesel. The catalytic degradation using HZSM-5 catalyst shows the high conversion of pyrolysis wax oil to light hydrocarbons. The liquid product obtained shows high gasoline range fraction as around 90% fraction and considerably high aromatic fraction in liquid product. Here, the experimental variable such as catalyst amount and reaction temperature was influenced on the product distribution.

• Journal of Marine Bioscience and Biotechnology
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• v.7 no.1
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• pp.1-10
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• 2015

Bio diesel has advantages to reduce GHG(Greenhouse Gas) compare with the fossil fuel by using oil comes from plant/animal sources and even waste such as used cook oil. The diversity of energy feeds brings the positive effects to secure the national energy mix. In this circumstance, micro-algae is one of the prospective source, though some technical barriers. We analyzed the bio diesel which was derived from Dunaliella tertiolecta LB999 through the BD100 quality specifications designated by the law. From that result, it is revealed that the oxidation stability is one of the properties to be improved. In order to find the reason for low oxidation stability, we analyzed the oxidation tendency of each FAME components through some methods(EN 14111, EN14112, EN16091). In this study, we could find the higher double bond FAME portion, the more oxidative property(C18:1${\ll}C18:3$) in bio diesel and main unsaturated FAME group is acted as the key component deciding the bio diesel's oxidation stability. It is proved experimentally that C18:3 FAME are oxidized easily under the modified accelerated oxidation test. We also figure out low molecular weight hydrocarbon and FAME were founded as a result of thermal degradation. Some alcohol and aldehydes were also made by FAME oxidation. In conclusion, it is necessary to find the way to improve the micro-algal bio diesel's oxidation stability.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1045-1050
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• 2014

$N_2O$(Nitrous Oxide) is known as the third major GHG(Green House Gas) following $CO_2$(Carbon Oxide) and $CH_4$(Methane). The GWP(Global Warming Potential) factor of $N_2O$ is 310 times as large as that of $CO_2$ because $N_2O$ in the atmosphere is very stable, and it becomes a source of secondary contamination after photo-degradation in the stratosphere. Investigation on the cause of the $N_2O$ formation have been continuously reported by several researchers on power sources with continuous combustion form, such as a boiler. However, in the diesel engine, research on $N_2O$ generation which has effected from fuel components has not been conducted. Therefore, in this research, author has investigated about $N_2O$ emission rates which was changed by nitrogen and sulfur concentration in fuel on the diesel engine. The test engine was a 4-stroke direct injection diesel engine with maximum output of 12 kW at 2600rpm, and operating condition of that was set up at a 75% load. Nitrogen and sulfur concentrations in fuel were raised by using six additives : nitrogen additives were Pyridine, Indole, Quinoline, Pyrrol and Propionitrile and sulfur additive was Di-tert-butyl-disulfide. In conclusion, diesel fuels containing nitrogen elements less than 0.5% did not affect $N_2O$ emissions in the all concentrations and kinds of the additive agent in the fuel. However, increasing of the sulfur additive in fuel increased $N_2O$ emission in exhaust gas.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.952-964
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• 2005

The diesel-degrading activities of biofilms sampled from petroleum-contaminated groundwaters in urban subway drainage systems were examined in liquid cultures, and the microbial populations of the biofilms were characterized by denaturing gel gradient electrophoresis (DGGE) and 16S rDNA sequence analysis. Biofilm samples derived from two sites (19 K and 20 K) at subway Station N and Station I could degrade around $80\%$ of applied diesel within 20 and 40 days, respectively, at $15^{\circ}C$, and these results were strongly correlated with the growth patterns of the biofilms. The closest phylogenetic neighbor of a dominant component in the 19 K biofilm was Thiothrix fructosivorans strain Q ($100\%$ similarity). Four dominant strains in the 20 K biofilm were closely related to Thiothrix fructosivorans strain Q ($100\%$ similarity), Thiothrix sp. CC-5 ($100\%$ similarity), Sphaerotilus sp. IF14 ($99\%$ similarity), and Cytophaga-Flexibacter-Bacterioides (CFB) group bacterium RW262 ($98\%$ similarity). Three dominant members in the Station I biofilms were very similar to uncultured Cytophagales clone CRE-PA82 ($91\%$ similarity), Pseudomonas sp. WDL5 ($97\%$ similarity), and uncultured CFB group bacterium LCK-64 ($94\%$ similarity). The microbial components of the biofilms differed depending on the sampling site. This is the first report on the isolation of clones highly similar to Thiothrix fructosivorans and Thiothrix sp. from biofilms in petroleum-polluted groundwaters, and the first evidence that these organisms may play major roles in petroleum degradation and/or biofilm-development.

• Journal of Korea Soil Environment Society
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• v.2 no.3
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• pp.23-30
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• 1997

The purpose of this study was to evaluate effects of solids content and mixing speed in treatment of petroleum hydrocarbon contaminated soils using a slurry-phase bioreactor. Performance results on slurry-phase bioremediation of diesel fuel contaminated soil were generated at the bench-scale level. The fate of TPH(Total Petroleum Hydrocarbon) was evaluated in combination with biological treatment. Abiotic and biotic fate of the TPH were determined using soil not previously exposed to compounds in diesel fuel. The reactor volume for given throughput can be reduced by maximizing the solids content. Applications of 50% and 20% solids content(dry weight basis) were showed a little difference(57.5% : 61.6%) in biological TPH removal rate each other. Mixing and particle suspension are critical to desorption and biological degradation. In this standpoint, this study was performed using two mixing speed. When the reactor was operated at 70rpm, it had a better result in the particle suspension and TPH removal rate than the reactor with mixer rotated at 20rpm. In the reactor applied 20rpm, it was resulted in failure of particle suspension.