• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.217-225
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• 1998

분쇄한 FRP(Fiver-Reinforced Plastics) 폐기물을 사용한 폴리머 모르타르의 물성에 고나하여 조사하였다. 분쇄한 FRP 폐기물을 시멘트 모르타르의 세골재로 재활용하기 위하여 세골재에 대하여 0~50wt% 치환.사용하였고, FRP 폐기물의 사용으로 나타나는 강도 저하현상을 보완하기 위하여 3종류 폴리머 혼화제의 첨가량을 변화시켜 각종 공시체를 제작하였다. 폴리머 혼화제로서는 styrene-bytadiene rubber(SBR) 라텍스, polyacrylic ester(PAE) 에멀젼 및 ethylene-vinyl acetate(EVA)에멀젼을 사용하였다. 분쇄한 FRP 폐기물을 사용한 시멘트 모르타르에 폴리머 혼화제를 첨가하여 만든 폴리머 시멘트 모르타르는 폴리머 혼화제를 첨가하지 않은 모르타르보다 압축 및 휨강도가 크게 증가하였다. 폴리머 시멘트비 10wt%에서 세골재 대용으로 분쇄한 FRP 폐기물의 적정 치환량은 20wt%로 나타났다. 8$0^{\circ}C$에서 가열양생하여 제조한 폴리머 시멘트 모르타르는 폴리머 시멘트비 10wt%이하에서 표준양생한 모르타르보다 강도가 저하되었다. 폴리머 시멘트 포르타르의 흡수율은 폴리머 시멘트비가 증가함에 따라 크게 감소하였다.

• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.129-138
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• 2008

The characteristics of beneficiating kaolin mineral by liberation (selective grinding) and air classification have been investigated, comparing the grinding rates of ball mill and impact mill. The ore was ground using a ball mill and a impact mill to evaluate the grindability of the two grinding methods based on the constant production amount of fine particles in size less than 325 mesh. Then, the fine product was further separated into two fractions using an air-classifier and each fraction was chemically analyzed to compare the beneficiation efficiency of the two grinding methods. The chemical grade of kaolin mineral decreased as increasing the grinding rate of both the mills. particularly in the case of ball mill because of overgrinding impurities such as quartz and feldspar. In the case of the ball milling, the fine fraction less than 325 mesh was air-classified at a cutting point of $43\;{\mu}m$. The production rate of the air-classified concentrate was found to be 66.2 wt%, removing 5.3% of $Fe_2O_3$ and 34.6% of CaO. Under the same conditions mentioned above with the impact mill, the production rate of the air-classified concentrate was 64.4 wt%, removing 34.2% of $Fe_2O_3$, 67.6% of CaO and 25.0% of $TiO_2$. Therefore, our results indicate that impact mill is superior to ball mill in terms of impurity removal.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.931-934
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• 2002

To establish the optimal conditions for increasing oil yields from grape seed, extraction solvent, extraction time, and temperature were examined. Using grinding, grinding and roasting, grinding and steaming, and grinding, roasting, and steaming methods. Pressing extraction method resulted in 34.0% oil yield. Grinding and roasting, grinding and steaming, and grinding, roasting, and steaming gave 64.3, 63.0, and 65.6% yield, respectively. Ether solvent treatment resulted in 77.4 and 80.9% recoveries after 24 and 48 h static, respectively. The results of sensory evaluation revealed, oils extracted under optimal condition showed the best flavor, aroma, and whor, followed by grinding, grinding and roasting, grinding, roasting, and steaming, and grinding and steaming. Taking these results together, the optimal methods for oils extraction from grape seed were as follows: grape seed ${\rightarrow}$ washing ${\rightarrow}$ drying ${\rightarrow}$ roasting ($95{\sim}100^{\circ}C$ for 20 min) ${\rightarrow}$ cooling (room temperature) grinding ${\rightarrow}$ (0.5 mm>) ${\rightarrow}$ steaming ($0.8{\sim}0.9\;kg{\cdot}f/cm^2$ for 10 min) ${\rightarrow}$ pressing ($1st\;400\;kg/cm^2\;for\;2{\sim}3\;min,\;2^{nd}\;550{\sim}600\;/cm^2$ for 10 min, $3^{rd}\;700kg/cm^2$ for 60 min) ${\rightarrow}$ oils (yield $;85{\sim}90%$).

• Journal of Ginseng Research
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• v.26 no.2
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• pp.79-84
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• 2002

In this study, cell cracker method as a non-collision method was evaluated for the possibility in manufacturing red ginseng powder. In color value of red ginseng powder, the L values indicating brightness were 68.18 for hammer mill (group A) and 72.08 for cell cracker (group B). The a values (redness) and b values (yellowness) were 4.21 26.56 for group A and 5.73, 28.36 for group B, respectively. As an extraction time increased, the absorbances at 420 nm of water extract of both groups were increased. In the loose bulk density, tapped bulk density and volume reduction radio indication the of powder in group A were less than those in group B. In both groups, the angles of side of red ginseng powder were shown less value than the angles of side of the powder. These two angles in group A were lets than those in group B. In sensory evaluation, the touchness between both groups was, not observed significant difference. In the contrary, the color and flavor, main factors affecting the overall quality of red ginseng powder product of group B were shown superior to those of group A. The overall preference of group B was shown higher than that of group A.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.685-691
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• 2013

Ibuprofen, non-steroidal anti-inflammatory drugs; NSAIDs, is a highly crystalline substance with the pharmaceutical properties of poor solubility and low bioavailability. The size reduction of ibuprofen is needed to improve the solubility. The objective of this study is to optimize the grinding condition of ibuprofen. Grinding of ibuprofen was carried out using a planetary mill. Grinding parameters were optimized using Box-Behnken experimental design method. The physical characteristics of ground ibuprofen were investigated for the particle size by particle size analyzer, for the crystal size by X-ray diffraction (XRD), and for the tensile strength by tensile/compression tester. The optimum conditions for the milling of ibuprofen were 290 rpm of the revolution number of mill, 24.6 g of the weight of sample, and 10 minutes of grinding time. The measured value of the particle size of ground ibuprofen at these optimum conditions was $13.5{\mu}m$. The results showed that the crystal size of ibuprofen was reduced by the planetary milling process. In case the relative density of the tablets formulated of ground ibuprofen was range of 0.85~0.90, the tensile strength of them was range of 1$2{\sim}14Kg_f/cm^2$.

• Journal of the Mineralogical Society of Korea
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• v.20 no.2 s.52
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• pp.135-145
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• 2007

The needs for the ultra fine particles have been increased in preparation field of raw powders such as fine ceramics and high functional products. In this study, a series of wet grinding experiments were carried out on inorganic powders such as calcite, pyrophyllite and talc by a stirred ball mill. The particle size distribution of ground products of each test material fur a given grinding time was found to be expressed by the grinding rate (selection function) which was obtained from the grinding kinetics analysis. The median diameter decreased from 6.49 to $0.47{\mu}m$ in calcite, and decreased from 3.91 to $1.14{\mu}m$ in pyrophyllite. However, in talc, median diameter was decreased a little bit from 10.30 to $6.67{\mu}m$. The grinding rate changing on calcite and pyriphyllite were similar at the same conditions. However, in the case of talc, it was observed that the grinding rate was not increased compared to other samples.

• Journal of Sericultural and Entomological Science
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• v.44 no.2
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• pp.82-86
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• 2002

Silk sericin powder was prepared by mechanical treatment from culled-cocoon extract of Bombyx mori silkworm. The physical and structural characteristics of sericin powder were investigated by instrumental analysis. The solubility of sericin powder was decreased nearly half of sericin lyophilized. Amino acid analysis showed that arginine content was decreased from 3.72% to 0.03∼0.07%. XRD showed that molecules of sericin were somewhat regularly arranged by mechanical treatment. On the other hand, FT-IR showed the molecular vibration of silk sericin was not induced by mechanical treatment. Thermal properties also did not changed.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.179-190
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• 2003

The grout based on solution type makes it difficult to get the improvement of ground strength and the effefct of water curtain because it has lower strength and durability than suspension type. Nowadays, the technology of particle acceleration, that enhance the material permeability, such as grout based on solution type, and inexpensive grout, is being required. For these reasons, in this study, using wet milling system, we evaluated physical properties of manufactured factors such as water-cement ratio of particles before being milled, optimum milling capacity by controlling milling time and rpm, viscosity of materials, permeation coefficient, and unconfined compressive strength. Also, using micro wet milling apparatus which could manufacture ordinary Portland cement and high speed shear mix which could forcefully separate conglomerate particles in situ, we performed electrical resistivity investigation and falling head permeability tests to analyze differences of grouting effects. From these results, we found that the permeability of the applied equipment was much superior, and in the case of using high speed shear mixer, particles of grout material were well separated.

• Journal of the Korean Chemical Society
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• v.27 no.3
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• pp.224-232
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• 1983

The effects of ball-milling time on solid state reactions in the system $BaCO_3-Fe_2O_3$ and the magnetic properties of Ba-ferrite 4(BaFe_{12}O_{19})$ have been studied. $BaCO_3-Fe_2O_3 $mixtures were prepared by ball-milling for varying lengths of time; 5, 15, 30, 80 and 200 hours. Techniques employed were thermogravimetry, X-ray diffraction analysis, scanning electron microscopy and B-H curve tracer. It is shown that the aggregation states and superparamagnetic size fractions obtained by increasing ball-milling time have remarkable effects on solid state reactions and magnetic properties of Ba-ferrite.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.163-169
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• 2003

The vertical roller mill is the important machine grinding and mixing various crude materials in the manufacturing process of portland cement. Table liner is one of grinding elements of vertical roller mill and is subjected to the cyclic bending stress by rollers load and the centrifugal force by rotation of table. It demands $4{\times}10^7$ cycle but has $4{\times}10^6{\sim}8{\times}10^6$ cycle. It fractures at the edge of grinding path of outside roller. The repair expense for it amounts to 30% of total maintenance of vertical roller mill. Therefore, this study shows the fracture mechanism of table liner for vertical roller mill using HDM and fatigue analysis