• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.1
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• pp.49-54
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• 2011

In order to develop the methods for exposure assessment and find susceptibility markers for the workers who are exposed to low doses of toluene, xylene and other chemical in petroleum industries, we investigated the application of P-450 expression in human lymphocytes utilizing mouse monoclonal anti-rat CYP2B1/2, the levels of toluene and xylene in air and their metabolite levels in urine with the levels of expressed CYP2B1/2 proteins. The general characteristics such as age, smoking and drinking habit were no significant difference between the control and exposed workers, but the working durations and working hours were significantly different. Workers in exposed group were exposed to the mean of 2.1 ppm (range, 0.00-4.54) of toluene and 0.3 ppm (rang, 0.00-1.23) of xylene. The mean concentration of urinary hippuric acid was low and less than 1/5 of the biological exposure index recommended by the Ministry of Employment and Labor Korea. Methyl hippuric acid in urine was not detected in control and exposed workers. Also, there were no significant differences in the levels of the urinary metabolites between the control and exposed group. When chemiluminescence dot blottings were carried out utilizing mouse monoclonal antibody against CYP2B1/2, the strong density dots corresponding to a mouse monoclonal antibody was observed in the human lymphocytes from the exposed workers. These results suggested that the chemiluminescence dot blot assay for CYP of lymphocytes should be valuable for identifying CYP expression as biomarkers in the workers exposed to toluene and xylene.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.2
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• pp.41-48
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• 2011

In this study, the soil remediation by landfarming was carried out using microbial activators. Feasibility studies and reduction capacity of TPH(Total Petroleum Hydrocarbons) were investigated in order to find out how fast and eco-friendly the contaminated soil can be recovered. The lab-test confirmed not only the performance and degradation efficiency of microbial activators but also the effect of TPH reduction in the contaminated soil. The optimum growth conditions for indigenous microorganisms were identified using microbial activators. Based on the results of TPH removal, although there had been a little of difference in between natural decomposition and microbial activators until 20 days, the sample groups of microbial activators were higher than the control ones after 20 days. Microbial activators were applied to the field experiments on landfarming. Based on the results of removal rate in each floor of soil, it was found that the removal rates were 85.8 % in the upper, 84.4 % in the middle, and 66.10 % in the bottom. Considering that the reduction rate of TPH for the control group averaged 71.1%, the microbial activators might not be fully transferred into the bottom, which resulted from the piles of soil. As the piles have already reached 1 m in the field experiments, the low piles of soil under 0.6 m may enhance the treatment efficiency of TPH.

• Clean Technology
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• v.25 no.4
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• pp.316-323
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• 2019

In order to enhance combustion efficiency and reduce atmosphere pollutants, it is essential to measure carbon monoxide (CO) concentration precisely in combustion exhaust. CO is the important gas species regarding pollutant emission and incomplete combustion because it can trade off with NOx and increase rapidly when incomplete combustion occurs. In the case of a steel annealing system, CO is generated intentionally to maintain the deoxidation atmosphere. However, it is difficult to measure the CO concentration in a combustion environment in real-time, because of unsteady combustion reactions and harsh environment. Tunable Diode Laser Absorption Spectroscopy (TDLAS), which is an optical measurement method, is highly attractive for measuring the concentration of certain gas species, temperature, velocity, and pressure in a combustion environment. TDLAS has several advantages such as sensitive, non-invasive, and fast response, and in-situ measurement capability. In this study, a combustion system is designed to control the equivalence ratio. Also, the combustion exhaust gases are produced in a Liquefied Petroleum Gas (LPG)/air flame. Measurement of CO concentration according to the change of equivalence ratio is confirmed through TDLAS method and compared with the simulation based on Voigt function. In order to measure the CO concentration without interference from other combustion products, a near-infrared laser at 4300.6 cm^-1 was selected.

• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.36-42
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• 2020

In order to investigate the effect of the oxidation process on thermal properties of the pitch, the oxidized pitch was prepared by changing the oxidation temperature. Thermal properties of the pitch were analyzed using thermogravimetric analysis (TGA), and it divided into three sections as A (25~100 ℃), B (250~550 ℃) and C (550~800 ℃) by derivative thermogravimetry (DTG) graph behavior. In the A section, the was reduced because the moisture contained in the pitch was removed. In the B section, as the oxidation temperature increased, the thermal stability of the pitch is improved. Because the degree of aromaticity and molecular weight of the pitch increased with increasing oxidation temperature. In contrast, the results of the C section were shown opposite of B section. Because the introduced C-OH, C-O-C, and C=O bonds were decomposed, and the resulting oxygen compounds induced the combustion reaction of the pitch.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.79-84
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• 2008

This paper describes the application of bioluminescence stimulating agents on a genetically engineered microorganism, Pseudomonas putida mt-2 KG1206, to monitor toluene analogs using in groundwater samples from petroleum hydrocarbon contaminated sites. The maximum bioluminescent response with pure chemicals followed in the order: m-methyl benzyl alchohol > m-toluate > toluene > m-xylene > benzoate > p-xylene > o-xylene. Generally, the bioluminescence production of strain mixed with groundwater samples was dependent on the contaminated total inducer concentrations. However, few samples showed opposite results, where these phenomena may be caused by the complexicity of environmental samples. Two chemicals, SL(sodium lactate) and KNO$_3$, were tested to determine a better bioluminescence stimulant. Both chemicals stimulate the bioluminescence activity of strain KG1206, however, a slightly high bioluminescence was observed with nitrogen chemical. This selected stimulant was then tested on samples collected from contaminated groundwater samples. The bioluminescence activity of all samples mixed with the strain was stimulated with KNO$_3$ amendment. This suggests that the low bioluminescence activity exhibited by the environmental groundwater samples can be stimulated by amending the culture with a proper agent, such as nitrogen compound. These findings would be useful, especially, when strain was used to monitor the groundwater samples contaminated with low inducer contaminants. Overall, the results of this study found the ability of bioluminescence producing bacteria to biosensor a specific group of environmental contaminants, and suggest the potential for more efficient preliminary application of this engineered strain in a field-ready bioassay.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.3
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• pp.169-174
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• 2021

Today, plastic waste has become a critical social issue due to the increasing of plastic consumption. Korean annual per capita plastic consumption was 132 kg, the most plastic consuming country in the world. Internationally, Carbon Neutral Agreement is underway due to global warming, consumers' interest and needs for biomass-based plastics has also been increased. In this study, film was produced by adding composite use additives to the biomass-based plastics according to concentration, and the resulting changes in discharge volume, melt index, and tensile strength were investigated. Melt index (MI) was significantly higher in PLA and PBAT than in petroleum-based resin LLDPE and LDPE. Also, among the same resin or in the same treatment group, MI has been increased when the heating temperature is increased. The discharge volume and gravity of the BDP-2 to which 4% compatibilizer was added were found to be higher among all treatments, while the tensile strength of MD and TD was also higher. BDP-2 was suitable to the film producing methods for biodegradable film production.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.2
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• pp.144-151
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• 2016

This study effect of engine oils on regulated fuel economy and emissions including particulate matter (PM) to provide basic data for management of engine oil in vehicles. Three engine oils (Group III base oil, Group III genuine oil with additive package and synthetic oil with poly alpha olefins (PAOs)) were used in one gasoline, one LPG(liquefied petroleum gas) and two diesel vehicles. In the case of diesel vehicles, one is a diesel vehicle without DPF (diesel particulate filter) other is a diesel vehicle with DPF. In this study, the US EPA emission test cycle FTP-75, representing city driving, was used. HORIBA, PIERBURG, and AVL gas analyzers were used to measure the fuel economy and regulated emissions such as CO, NOx, and THC. The number of PM was measured using a PPS (pegasor particle sensor). And, the shape of PMs was analyzed by SEM (scanning electron microscope). The effects of oil type on fuel economy, exhaust gas, and PM were not significant because engine oil consumption by evaporation and combustion in the cylinder is very tiny. Fuel and vehicle type were dominant factors in fuel economy and emissions. HC emission from gasoline vehicles was higher than that from other vehicles and NOx emission from diesel vehicles was higher than that from other vehicles. The number of PM was not affected by the engine oil, but by the driving pattern and fuel. The shapes of the PM, sampled from each vehicle using any test engine oil, were similar.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.3
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• pp.247-256
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• 2012

Stable carbon isotope ratio of oil components are known to be unaffected by weathering processes and thus has been widely used to determine the origin of spilled oil. In this study, molecular index and composition of stable carbon isotope in 15 crude oils and petroleum product were analyzed and used as oil fingerprints to determine the discriminating power of each fingerprinting method among target crude oils. Through the fingerprints of alkane distribution only Bintulu and B-C(1%) were distinguishable from other crude oils. The pristane/phytane ratio can classify the crude oils into three groups but differentiation of crude oils within a group was impossible using the ratio. The crude oils of A.L., A.S.L., Foroozan and B-C(1%) were differentiated from the other oils using PAH source recognition indexes of C2D/C2P and C3D/C3P. The usage of 4-mD/1-mD and 2/3-mD/1-mD ratio was able to distinguish A.S.L., Bintulu and Oman from the other crude oils. However the PAH source recognition ratios in the other crude oils were similar and thus they were impractical to be used for source identification among the target crude oils. Stable carbon isotope ratios of alkanes were able to uniquely specify each crude oil in the plot of ${\delta}^{13}C_{C21}$ and ${\delta}^{13}C_{C25}$ except A.L., A.M., Qatar-Marine, B-C(1%). The oil fingerprinting method using stable carbon isotope ratios of individual alkane compounds showed more discriminating power among the target crude oils than the conventional source recognition indexes of PAHs or alkanes.

• The Journal of the Petrological Society of Korea
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• v.19 no.1
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• pp.89-101
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• 2010

To constrain the depositional ages of the Gyeongsang sedimeantary formations, SHRIMP U-Pb ages were determined from detrital zircons in three samples: (1) a pebble-bearing sandstone from the lowermost Jinju Formation of the Sindong Group and (2) two conglomerates from the Silla Conglomerate of the Hayang Group. Their concordia ages are $112.4{\pm}1.3(2{\sigma})$ Ma and $110.4{\pm}2.0(2{\sigma})$ Ma respectively. Such ages represent the maximum deposition ages for the lowermost Jinju Formation and Silla Conglomerate, indicating the deposition of the Jinju Formation started from late Aptian and lasted to early Albian, then deposition of the rather thin Chilgok Formation and Silla Conglomerate was followed during the Albian. The age distribution of the analyzed detrital zircons indicates the presence of protoliths, or zircons derived from them, regarding a wide span of igneous activities from Mesozoic to Archean. Among such ages, there are Mesoproterozoic, Neoproterozoic and Paleozoic igneous activities, which have not been known or seldom reported from Korean peninsula. These ages further suggest the possible presence of rocks with such ages during the deposition periods or their derivation through a long river system developed into the continents at the time of deposition.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.342-349
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• 2017

Polylactic acid (PLA) has been highlighted as an alternative renewable polymer for the replacement of petroleum-based plastic materials, and is considered to be biodegradable. On the other hand, the biodegradation of PLA by terminal degraders, such as microorganisms, requires a lengthy period in the natural environment, and its mechanism is not completely understood. PLA biodegradation studies have been conducted using mainly undefined mixed cultures, but only a few bacterial strains have been isolated and examined. For further characterization of PLA biodegradation, in this study, the PLA-degrading bacteria from digester sludge were isolated and identified using a polymer film-based screening method. The enrichment of sludge on PLA granules was conducted with the serial transference of a subculture into fresh media for 40 days, and the attached biofilm was inoculated on a PLA film on an agar plate. 3D optical microscopy showed that the isolates physically degraded the PLA film due to bacterial degradation. 16S rRNA gene sequencing identified the microbial colonies to be Pseudomonas sp. MYK1 and Bacillus sp. MYK2. The two isolates exhibited significantly higher specific gas production rates from PLA biodegradation compared with that of the initial sludge inoculum.