• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.4
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• pp.417-422
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• 2010

Low temperature diesel combustion was achieved via a combination of late injection timing ($8.5^{\circ}$ CA BTDC to $0.5^{\circ}$ CA BTDC) and heavy exhaust gas recirculation (37% to 48%) with ultra low sulfur Swedish diesel fuel in a 1.7L common rail direct injection diesel engine. When injection timing is retarded at a certain exhaust gas recirculation rate, the particulate matter and nitrogen oxides decease simultaneously, while the hydrocarbon and carbon monoxide increase. Hydrocarbon speciation by gas chromatography using a flame ionization detector reveals that the ratio of partially burned hydrocarbon, i.e., mainly alkenes increase as the injection timing is retarded and exhaust gas recirculation is increased. The two most abundant hydrocarbon species are ethene which is a representative species of partially burned hydrocarbons, and n-undecane, which is a representative species of unburned hydrocarbons. They may be used as surrogate hydrocarbon species for performing a bench flow reactor test for catalyst development.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.58-64
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• 2024

Approximately 250 marine oil spill accidents have occurred in Korea, with profound impact on local communities and the environment. The restoration process necessitates significant resources and costs to return affected areas to their pre-accident state. In accordance with the polluter pays principle, compensation is demanded from polluter, as stipulated in both international conventions and national laws. Consequently, investigations are conducted to determine civil and criminal liability. As the importance of investigation actors in oil spill accidents increases, standards such as CEN 15522-2 and ASTM D 3248 are employed to determine the similarity between the spilled oil and the oil of the suspected ship. Among these standards, CEN 15522-2, the most actively used European standard, underwent its third revision and is now known as EN 15522-2, as of 2023. This study used EN 15522-2 to analyze samples from marine oil spill accidents that occurred in Korea. The results indicated that, considering the characteristics of domestic spills where light fuel oil spills account for more than 40%, the application of EN 15522-2, which includes low-boiling point substances such as Adamantanes, was confirmed to be highly effective.

• Analytical Science and Technology
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• v.27 no.6
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• pp.357-363
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• 2014

Isoprene is a one of the biogenic volatile organic compounds (BVOCs) and it is known as a source of the tropospheric ozone and formaldehyde. In addition, isoprene is a trace component of the exhaled breath and it is a potential biomarker for the diagnosis of diseases such as lung cancer. In these regards, isoprene gas standards are required for the accurate measurement of isoprene in air samples. To establish a standard for isoprene gas, gravimetric preparation and characterization of primary gas standards were studied. The primary gas standards were produced independently in 4 aluminum cylinders and concentrations were examined by GC-FID. As a result, the uncertainty of the gravimetric preparations including purity of the raw material was 0.01% and reproducibility of the preparation of independent 4 cylinders was 0.08%. The primary gas standards for isoprene showed 14 months of long-term stability. The relative expended uncertainty of 2.8% (95% of confidence level, k=1.96) was assigned to the certified value of 10 ${\mu}mol$/mol level of isoprene based on the quantitative evaluation of the purity, weighing, reproducibility, adsorption and long-term stability.

• Analytical Science and Technology
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• v.18 no.6
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• pp.552-558
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• 2005

A type of dimethyl sulfide gas CRM in the ppb level was developed for the analysis of trace-level odorous gas in environmental atmosphere. The concentration of dimethyl sulfide ($(CH_3)_2S$) was 10 umol/mol level in the cylinder filled with nitrogen, 1500 psi. And the variability of the concentration for 3 years was about 0.1% due to the adsorption or instability of $(CH_3)_2S$. The gas standards produced simultaneously in 4 bottles and examined by GC-FID were shown with 0.4%, reproducibility of preparation and 0.25%, standard uncertainty due to weighing and purity. The relative expended uncertainty of 1.1% (95% of confidence level, k=2) was assigned to the certified value of 10 umol/mol level of $(CH_3)_2S$ after quantitative evaluation on the purity, mixing, weighing, analysis, adsorption and stability of dimethyl sulfide gas.

• Analytical Science and Technology
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• v.35 no.3
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• pp.116-123
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• 2022

Polymer bags, metallic canisters, and glass bottles have been used as containers for analyzing the volatile organic compounds (VOCs) in air. In this study, various sampling containers were compared to investigate the short-term stability of VOCs, that is, from the time they are sampled to the time they are analyzed. Polyvinyl fluoride (PVF), polypropylene (PP), polyester aluminum (PE-Al) bags, canisters, and glass bottles were used as sample containers. A 100 nmol/mol standard gas mixture of benzene, toluene, ethylbenzene, m-xylene, styrene, and o-xylene was used for the VOC comparison. Changes in the concentrations of samples stored for 10~20 day in each container were measured using a thermal desorption-gas chromatograph-flame ionization detector (TD-GC-FID). As a result, VOCs stored in a canister and two kinds of amber glass bottles have shown immaterial decreases in concentration in one week, and more than 80 % of the initial concentration was maintained for two weeks. In the case of polymer bags, the concentration of all VOCs, except benzene and toluene, were remarkably decreased below 70% of the initial concentration in one day. Particularly, ethylbenzene, xylene, and styrene have shown dramatic decreases in concentration below 30 % of the initial concentration in all polymer bags in one day.

• Analytical Science and Technology
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• v.19 no.6
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• pp.498-503
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• 2006

A type of dimethyl disulfide gas CRM in the ppb level was developed for the analysis of tracelevel odorous gas in environmental atmosphere. The concentration of dimethyl disulfide($(CH_3)_2S_2$) was $10{\mu}mol/mol$ level in the cylinder filled with nitrogen, 1500 psi. And the variability of the concentration for 2 years was about 0.14% due to the adsorption or instability of $(CH_3)_2S_2$. The gas standards produced simultaneously in 4 bottles and examined by GC-FID were shown with 0.4%, reproducibility of preparation and 0.25%, standard uncertainty due to weighing and purity. The relative expended uncertainty of 1.1%(95% of confidence level, k=2) was assigned to the certified value of $10{\mu}mol/mol$ level of $(CH_3)_2S_2$ after quantitative evaluation on the purity, mixing, weighing, analysis, adsorption and stability of dimethyl sulfide gas.