• Journal of Power System Engineering
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• v.18 no.6
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• pp.34-39
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• 2014

In this study, the structural analysis and the modal analysis are conducted to investigate the stress level, the deformation characteristics and the natural modes of the casing of a planetary gear reducer for a 800kW grade pulverizer mill. The casing is subjected to the load, 2800 kN, from the lump coals in the pulverizing process. Because of the symmetry, the half portion of the reducer casing is modeled for the stress analysis. But the full model is used to find out the eigenvalues and natural modes for the modal analysis. The contact conditions are applied between the thrust pad bearing and the adjacent contacting parts. The results shows that the casing structure has the sufficient strength and stiffness to support the load under consideration. ANSYS version 15 is employed to perform the numerical study.

• Journal of Power Electronics
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• v.9 no.5
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• pp.700-707
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• 2009

The coal mill used in the coal-fired power plants is modeled in view of the controller design rather than the educational simulator. The coal mass flow and the outlet temperature are modeled by reinvestigating the mass balance and heat balance models physically. The archived data from a plant database are utilized to identify the model parameters. It can be seen that the simulated model outputs are well matched with the measured ones. It is also expected that the proposed model is useful for the controller design.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.6
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• pp.790-797
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• 2011

We evaluated the antioxidant compounds and activity of the methanolic extracts of foxtail millet (FM), proso millet (PM), and sorghum (SG) using different pulverizing methods (pin mill and ultra fine). The particle size of the FM, PM, and SG were 102.12, 89.52, and $102.25\;{\mu}m$, respectively, using the pin mill pulverizer. The sizes were 9.43, 9.52, and $10.18\;{\mu}m$, respectively, using the ultra fine pulverizer. There was no difference in moisture, crude fat, ash, or protein content between the two different pulverizing methods. The total ${\gamma}$-oryzanol content of the FM using the pin mill and ultra fine pulverizers was 116.07 and $145.30\;{\mu}g$/g, respectively. The total polyphenol content of the SG using the pin mill and ultra fine pulverizers was 14.58 and 15.03 mg/g extract residue, respectively. There was no difference in total flavonoid or tannin content of the methanol extracts between the two different pulverizing methods. The major phenolic compounds in FM were pyrogallol, gallic acid, (+)-catechin, salicylic acid, ferulic acid, and rutin; in PM, they were pyrogallol, rutin, gallic acid, kaempfrol, and salicylic acid; in SG, they were (+)-catechin, salicylic acid, pyrogallol, myricetin, hesperidin and chlorogenic acid. SG had a higher radical scavenging activity than FM or PM extracts. The DPPH and ABTS radical scavenging activities of the SG extracts using the ultra fine pulverizer were 178.10 and 251.56 mg TE/g extract residue, respectively. We noted a significant correlation between free radical scavenging activity and polyphenolic compound.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1692_1693
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• 2009

In this paper, the outlet temperature of the coal mill is modeled by reinvestigating the heat balance models physically. The archived data from a plant database are utilized for identifying the model parameters. It can be seen that the simulated model outputs are well matched with the measured ones. It is also expected that the proposed model is useful for the controller design.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.353-358
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• 2012

This study was carried out to evaluate antioxidant and anticancer activity of crudes extracts from colored corn (Zea mays. L.) among particle size with different pulverizing methods (pin mill and ultra fine pulverizer). In cytotoxicity test using extracts from the flours grounded by pin mill and ultra fine pulverizer respectively, it showed that A-549 was the highest anticancer activity among in vitro using 4 cancer cell line types (Hep-G2, A-549, HCT-116 and MCF-7). Assessing the antioxidant activities of crude extracted from different pulverizing methods was measured by trolox equivalent antioxidant capacity (TEAC) and ferric reducing antioxidant power (FRAP). Higher scanvening activity against free radical was observed in the crude extracted from small particle size flours of colored corn than in those of the big particle size.

• Clean Technology
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• v.23 no.1
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• pp.73-79
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• 2017

Recently usage of biomass is increased in pulverized coal power plants for reduction of $CO_2$ emission. Many problems arise when thermal share of the biomass is increased, and milling of the biomasses is one of the most important problems due to their low grindability when existing coal pulverizer is used. Grindability of coal can be measured through the HGI (Hardgrove grindability index) equipment as a standard, but method of measuring biomass grindability has not been established yet. In this study, grinding experiment of coal and biomass was performed using a lab-scale ball mill. One type of coal (Adaro coal) and six biomasses (wood pellet (WP), empty fruit bunch (EFB), palm kernel shell (PKS), walnut shell (WS), torrefied wood chip (TBC) and torrefied wood pellet (TWP)) were used in the experiment. Particle size distributions of the fuels were measured after being milled in various pulverization times. Pulverization characteristics were evaluated by portion of particles under the diameter of $75{\mu}m$. As a result, about 70% of the TBC and TWP were observed to be pulverized to sizes of under $75{\mu}m$, which implies that they can be used as alternative biomass fuels without modification of the existing mill. Other biomass was observed to have low grindability compared with torrefied biomass. Power consumption of the mill for various fuels was measured as well, and the results show that lower power was consumed for torrefied biomasses. This result can be used for characterization of biomass as an alternative fuel for pulverized coal power plants.

• Korean journal of food and cookery science
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• v.29 no.2
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• pp.129-135
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• 2013

The objective of this research was to investigate physicochemical properties of waxy sorghum flours by different milling methods (pin mill and ultra fine mill). Four different sorghum flours were used for the experiments ; PWS (pin milled whole sorghum flour), PS (pin milled sorghum flour without bran), UFWS (ultra fine milled whole sorghum flour), UFS (ultra fine milled sorghum flour without bran). The contents of crude ash and total dietary fiber were the highest in PWS. Amylose content of pin milled sorghum flour was higher than that of ultra fine milled flour. The mean particle size of pin milled flours was six times lager than ultra fine milled flours. The L values of UFS and UFWS were higher than those of PS and PWS, whereas a and b values were higher in PWS. The water binding capacity was highest in UFWS, and solubility was higher in PS and UFS. Swelling power of flours was highest in UFS. The damaged starch content was higher in PS and UFS, which means damaged starch of sorghum flours significantly affected by polishing than milling method. The pasting properties were higher in the pin milled flours. Initial pasting temperature of pin milled flour was ranging from 70.5 to $73.1^{\circ}C$, which are higher than ultra fine milled flour ($68.6^{\circ}C$). The contents of total polyphenol were higher in PWS and UFWS than those of PS and UFS, there was no difference between the two milling methods. The results of this study indicate that physicochemical properties of sorghum flour were affected by milling methods as well as bran.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.4
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• pp.313-319
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• 2015

This study relates to an investigation into semi-dry manufacturing process of BP sludge based on non-heating production method. In this study, we conducted a research into reduction of water content ratio which arose from mixture of BP by-products of high water content ratio(50% or higher) with industrial by-products to use such BP by-products as construction materials in large quantity. We measured the reduction rate of water content ratio at the feeding ratio of water content reduction agent(1:0.5) in BP by-products. The results showed that water content ratio was the lowest with 18.5% in the mixture of PA+CFA(1:0.5). Moreover, water content ratio ranged between approximately 9.2% and 11.4% at the age of 1 day to 2 days at the aging temperature of $20-30^{\circ}C$, suggesting that the water content ratio was in the range within 10% which was a level suitable for use as construction material in this study. Meanwhile, we compared and evaluated the physical properties of non-heated BP by-products based on post-aging pulverization method. The results showed that there was no significant difference, depending on pulverization method. When production efficiency and economic feasibility were taken into consideration, it was found desirable to use fine particle pulverizer or pin mill enabling continuous production.