• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2010.04a
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• pp.132-137
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• 2010

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.100.1-100.1
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• 2001

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.17-22
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• 2009

The mixotrophic growth with methanol plus thiosulfate was examined in nutrient-limited mixotrophic condition for Methylobacterium goesingense CBMB5 and Methylobacterium fujisawaense CBMB37. Thiosulfate oxidation increased the growth and protein yield in mixotrophic medium that contained 150mM methanol and 20mM sodium thiosulfate, at 144 h. Respirometric study revealed that thiosulfate was the most preferable reduced inorganic sulfur source, followed by sulfite and sulfur. M. goesingense CBMB5 and M. fujisawaense CBMB37 oxidized thiosulfate directly to sulfate, and intermediate products of thiosulfate oxidation such as polythionates, sulfite, and sulfur were not detected in spent medium and they did not yield positive amplification for tested soxB primers. Enzymes of thiosulfate oxidation such as rhodanese and sulfite oxidase activities were detected in cell-free extracts of M. goesingense CBMB5, and M. fujisawaense CBMB37, and thiosulfate oxidase (tetrathionate synthase) activity was not observed. It indicated that both the organisms use the "non-S4 intermediate" sulfur oxidation pathway for thiosulfate oxidation. It is concluded from this study that M. goesingense CBMB5, and M. fujisawaense CBMB37 exhibited mixotrophic metabolism in medium containing methanol plus thiosulfate and that thiosulfate oxidation and the presence of a "Paracoccus sulfur oxidation" (PSO) pathway in methylotrophic bacteria are species dependant.

• Food Science of Animal Resources
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• v.36 no.6
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• pp.760-768
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• 2016

The present study was performed to determine the effect of dietary supplementation with processed sulfur on the quality and stability of vacuum packaged pork during aging time. All groups were designated into two groups; NP, a group fed basal diet and SP, a group fed basal diet and processed sulfur, 3 g/kg feed. Following vacuum packaging, Longissimus dorsi muscles were vacuum-packaged and stored under refrigerated condition ($1-2^{\circ}C$) for 21 d. Weight loss of the SP group was lower (p<0.05) than that of the NP group. Interaction effect of shear force and cooking loss was observed (p<0.05). Redness values of the SP group at 14 and 21 d after storage were higher than those of the NP group (p<0.05). Lipid oxidation and volatile basic nitrogen (VBN) levels in the SP group were retarded (p<0.05) compared to that of the NP group during storage. Aspartic and glutamic acid in SP were higher than in NP (p<0.1). There was no significant (p>0.05) difference in TPC between the both groups during storage. Therefore, vacuum packaged pork from pigs fed processed sulfur had better aging yield and storage stability than pork from pigs fed basal diet.

• Tribology and Lubricants
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• v.28 no.6
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• pp.321-327
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• 2012

Paraffin bio-based hydrotreated biodiesel(HBD) is originated from vegetable oil(the process can also be applied to animal fat) with the the chemical structure $C_nH_{2n+2}$. In the number of process of the oil or fat, the hydrogenation is significantly important to create a bio-based diesel fuel. This study is focused on lubricity characteristics of BTL diesel blends to use alternative diesel fuel in Korea. The BTL diesel are blended the different volume ratios (HBD 5(5 vol.% HBD - 95 vol.% diesel), HBD 10, HBD 20, HBD 30, HBD 40 and HBD 50. HBD with paraffin compounds showed a very high centane number, low sulfur content and free aromatic compound. Especially, the wear scar of HBD showed poor lubricity compared to automotive diesel due to the fuel composition, low sulfur content and free aromatic compound. Also, the lubricity specification of automotive diesel with different six HBD blends is within the limit by the Korean standards. Finally, HBD as an alternative diesel fuel is challengeable in transportation sector of Korea.

• Journal of the Korean Chemical Society
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• v.34 no.3
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• pp.260-266
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• 1990

The electrochemical behavior of N-methyl-2-amino-l-cyclopentene-l-dithiocarboxylic acid $(N-CH_3 acdc) and 2-amino-l-cyclopentene-l-dithiomethyl ester (S-CH_3 acdc) in DMF have been investigated by the use of polarography, cyclic voltammetry and coulometry. The dimer of N-CH_3 acdc is further oxidized at +0.98 V via 2-electron process to produce free sulfur atom and cyclization product. The ring formation between two dithio group occurs along with the elimination of one sulfur atom. The elimination of sulfur atom occurs via two electron oxidation process at + 0.98 V vs. Ag/AgCl electrode. However, the cyclization does not occur in the S-CH_3$ acdc.

• Elastomers and Composites
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• v.56 no.4
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• pp.223-233
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• 2021

In this study, epoxidized liquid isoprene rubber (E-LqIR) was used as a processing aid in a silica-filled natural rubber compound to improve the fuel efficiency, abrasion resistance, and oil migration problems of truck and bus radial tire tread. The wear resistance, fuel efficiency, and extraction resistance of the compound were evaluated according to the molecular weight of E-LqIR. Results of the evaluation showed that the E-LqIR compound had a lower chemical crosslink density than that of a treated distillate aromatic extract (TDAE) oil compound because of the sulfur consumption of E-LqIR. However, the filler-rubber interaction improved because of the reaction of E-LqIR with silica and crosslink with the base rubber by sulfur. As the molecular weight of E-LqIR increased, crosslink with sulfur was facilitated, and the filler-rubber interaction improved, resulting in improved abrasion resistance. The fuel efficiency performance of the E-LqIR compound was poorer than that of the TDAE oil compound because of the low chemical crosslink density and hysteresis loss at the free chain end of E-LqIR. However, the fuel efficiency performance improved as the molecular weight of E-LqIR increased.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.544-549
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• 2000

This study was performed to compare optimum analytical method for the contents of naturally occurring sulfur dioxide in foods and to investigate the contents of sulfur dioxide in foods in order to provide a fundamental data when distinguish between added and naturally occurring sulfur dioxide. The determination of the contents of sulfur dioxide in foods from the 20 kinds, 180 cases of samples has been analyzed by the optimized Monier-Williams method, modified Rankine method and Acid Distillation/Ion Chromatography. As a result of the study, the contents of naturally occurring sulfur dioxide in foods by the optimized Monier-Williams method showed from 1.02 to 43.87 ppm and highly content of 43.87, 15.37, 11.50, 11.21 and 10.60ppm were observed in garlic, platicodon, green onion, cabbage and onion, the others were less than 10.00ppm. The sulfur dioxide contents in green onion and garlic by modified Rankine method were showed to be 2.87 and 6.14ppm, respectively, the others were detected less than 2.50ppm. The contents of sulfur dioxide by Acid Distillation/Ion Chromatography showed 15.43, 9.82, 5.74, 5.37, 2.14 and 0.49ppm in garlic, cabbage, green onion, onion, potato and apple, respectively and the others were not detected. And the contents of sulfur dioxide in green onion, onion, cabbage and garlic showed higher levels of sulfur dioxide in these foods than the others because of the naturally occurring sulfur containing compounds. The optimized Monier-Williams method, which is the of official analytical method of Korean Food Code, was suitable for monitoring of sulfur dioxide of most foods. Acid Distillation/Ion Chromatography was thought to be adequate for sulfur containing foods such as green onion, onion and cabbage. In order to distinguish between added and naturally occurring sulfur dioxide, it is though to be need of the fundamental data for the contents of sulfur dioxide in sulfite-free foods and continue the investigation for it.

• Bulletin of the Korean Chemical Society
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• v.21 no.6
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• pp.628-634
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• 2000

Crosslink is the most important chemistry in a rubber vulcanizate. Degree and type of crosslinks of the vulcanizate determine its physical properties. Change of crosslink density and deformation of a rubber vulcanizate by thermal aging were studied using natural rubber (NR) vulcanizates with various cure systems (conventional, semi-EV, and EV) and different cure times (under-, optimum-, and overture). All the NR vulcanizates were deformed by the thermal aging at 60-100 $^{\circ}C.$ The higher the aging temperature is, the more degree of the deformation is. The undercured NR vulcanizates after the thermal aging were deformed more than the optimumand overcured ones. The NR vulcanizates with the EV cure system were less deformed than those with the conventional and semi-EV cure systems. The deformation of the NR vulcanizates was found to be due to change of the crosslink density of the vulcanizates. The crosslink densities of all the vulcanizates after the extraction of organic materials were also changed by the thermal ging. The sources to change the crosslink densities of the vulcanizates by the thermal aging were found to be dissociation of the existing sulfur crosslink and the formation of new crosslinks by free sulfur, reaction products of curing agents, and pendent sulfide groups.

• Asian Journal of Atmospheric Environment
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• v.6 no.1
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• pp.41-52
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• 2012

Particulate sulfate in $PM_{2.5}$, sulfur dioxide ($SO_2$) and size-segregated aerosol particle number concentrations were measured at a site ($32^{\circ}19'N$, $129^{\circ}59'E$) on the southwestern Japan coast from 5 March to 10 April, 2010. Results show frequent episodic increases of sulfate and $SO_2$. Compared to the average concentration of sulfate $4.4{\pm}2.7\;{\mu}g\;m^{-3}$ in the whole observation period, episodic sulfate reached $10.5-20.1\;{\mu}g\;m^{-3}$. The variation of sulfate always synchronized with aerosol particles in the size range of $0.1-0.5 {\mu}m$, indicating the episodic sulfate was a consequence of the increase of the sub-micron particles. $SO_2$ did not have remarkable increase in any episodes of sulfate increase. During the passage of low pressure systems which loaded Asian dust in postfrontal air, concentrated sulfate appeared right behind the front but before dust arrival, suggesting the dominance of dust-free particulate sulfate. Weather and backward trajectory analyses revealed that air parcels with high sulfate passed eastern and northeastern China or Korean peninsula before arriving at the site. In contrast, those with high $SO_2$ passed an active volcano, Mt. Sakurajima, about 100 km in the south, suggesting the $SO_2$ was more likely from the volcanic emission. The ratio of sulfate to total sulfur compounds $({SO_4}^{2-})/({SO_4}^{2-}+SO_2)$ was 0.31-0.89 in continentally originated air while was 0.25-0.43 in the air having passed the volcano, showing more efficient conversions of $SO_2$ to sulfate in the air from the continent. The close dependence of the conversion on humidity in the continentally originated air was confirmed.