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A comparison of spontaneous combustion susceptibility of coal according to its rank
Wantaek Jo,Ho Kyung Choi,Sangdo Kim,유지호,전동혁,Young-joon Rhim,Jeong-hwan Lim,Si-hyun Lee 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.5
This study investigated spontaneous combustion susceptibility of coal according to the rank. To estimate the spontaneous combustion susceptibility of coal, both crossing-point temperature (CPT) measurement and gas analysis by using gas chromatography (GC) were performed. For the experiment, Eco coal and Kideco coal, Indonesian lignite,and Shenhua coal that is Chinese bituminous coal were used. The lignite such as Eco coal and Kideco coal contains more functional groups that easily react to oxygen more so than Shenhua coal. For this reason, the lignite is more easily oxidized than bituminous coal at low temperature, which results in high O2 consumption, increase in CO and CO2 generation,and low CPT. Although the CPT of Eco coal and Kideco coal is identical to each other as they are the lignite,Kideco coal has a lower initial oxidation temperature (IOT) and maximum oxidation temperature (MOT) than those of Eco coal. This means that although each coal has the same rank and CPT, spontaneous combustion susceptibility of coal may vary because the initial temperature of the coal at which oxidation begins may be different due to the substances that participate in oxidation.
최호경,Wantaek Jo,김상도,유지호,전동혁,Young-joon Rhim,Jeong-HwanLim,Si Hyun Lee 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.12
We compared the susceptibility to spontaneous combustion of low-rank coals dried by four different pro-cesses: flash drying, fluidized bed drying, non-fried carbon briquetting, and coal-oil slurry dewatering. The coals werecharacterized by FT-IR and XPS analysis. A crossing-point temperature (CPT) was estimated as a comparison criterionof the susceptibility of the coals to spontaneous combustion. O2, CO, and CO2 emissions during the CPT measurementwere also compared. The FT-IR and XPS analysis revealed that some of the oxygen functional groups on the surfaceof the coal were removed when the coal underwent the drying process. This phenomenon was particularly noticeablein the coal dried by oil. Accordingly, the CPT of the coal that went through this drying process was high. Among thesamples, the coals dried by oil showed the highest CPT.
Modification of the characteristics of silkworm powder by treatment with alkaline protease
( Sungkuk Kim ),( Youyoung Jo ),( Kwanggill Lee ),( Hyunbok Kim ),( Yongsoon Kim ),( Wantaek Ju ),( Daeun Jung ),( Haeyong Kweon ) 한국잠사학회 2015 International Journal of Industrial Entomology Vol.31 No.1
Enzymatic modification of proteins is often used to increase the biological activity of materials. Silkworm powder has been investigated as a functional food resource, but no study has been performed on its modification by commercial food enzyme. Therefore, this study aimed to determine the feasibility of such modification of silkworm powder by alkaline protease. The activity of the enzyme was confirmed using an azocasein assay. Subsequently the silkworm powder was hydrolyzed by enzymatic treatment. UV visible spectrometry showed that the supernatant of silkworm powder subjected to enzymatic treatment had a stronger absorption band than the untreated powder. SDS-PAGE electrophoresis showed that the molecular weight of silkworm powder decreased on enzymatic treatment. Thus the results indicate that commercial enzymes might be used to modify the characteristics of silkworm powder.
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마르셀죠나단히다잣 ( Marcel Jonathan Hidajat ),노종호 ( Jongho Noh ),박종범 ( Jongbeom Park ),홍재화 ( Jaehwa Hong ),김현효 ( Hyeonhyo Kim ),조완택 ( Wantaek Jo ) 한국화학공학회 2020 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.58 No.4
A ceramide-containing nanoemulsion was synthesized by using a High-Pressure Homogenizer (HPH) to observe its changes in properties and long-term stability. The droplet size, droplet distribution and zeta potential of nanoemulsion were examined by varying the pressure and the number of passes of the HPH. The increase in HPH pressure and number of passes decreased the average droplet size and made the nanoemulsion more uniform. However, beyond certain operating condition, the recombination between the droplets was confirmed due to droplet surface energy and emulsifier. This study also shows that the decrease in droplet size increased the nanoemulsion viscosity although only minimal changes occurred in the zeta potential. The formed nanoemulsion was then tested for its stability by storing it at 25 and 45 ℃ for 28 days. During the first week, the average droplet size increased due to recombination and then subsequently remained constant. We confirmed that ceramide nanoemulsion for industrial application could be synthesized by using HPH.