• Journal of Power System Engineering
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• v.18 no.6
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• pp.91-98
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• 2014

The purpose of this research is to investigate optimum machining conditions to improve the quality of die using the CAD/CAM system(Power Shape/Power Mill) and 3D printing. Surface roughness is widely used as an index for processing degree of accuracy. The Power Shape was used to model the shape of product. And the model shape is confirmed by 3D printing system(BFB-3000). Also, tool path and NC-codes were generated using Power Mill. Finally, the product was cut using CNC machine(NBS-2025). The cutting time and surface roughness were measured by measuring instrument. And then this process was repeated by changing the conditions to find optimal machining conditions. The surface roughness behavior with regard to specific factors were analyzed. Through this study, the optimal machining condition can be obtained.

• Transactions of Materials Processing
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• v.23 no.3
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• pp.145-150
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• 2014

Precision control of the slab is crucial for product quality and production economy in hot strip mills. The current study presents a new model for predicting width spread of a slab with a rectangular cross section during roughing. The model is developed on the basis of the extremum principle for a rigid plastic material and a three dimensional admissible velocity field. This model incorporates the effect of process variables such as the shape factor and the ratio of width to thickness. We compare the results of this model to 3-D finite element (FE) process simulations and also to results from a previous study.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.2
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• pp.1-12
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• 2002

Starch dissolved in paper-mill wastes, either as a result of poor retention on the paper web or recycling of surface-treated broke, was a major pollutant Laboratory tests were performed by using different kinds of starch as a surface treatment. It was concluded that the use of cationic starch can positively affect the level of starch dissolved in liquid effluents. When cationically modified starches were used for surface sizing, the starch was tightly bound to the paper fibers, it was not removed during the repulping of broke. The result of mill trial in fine paper manufacture for the application of low-viscosity cationic starches used in size press reduced COD load in the effluents and increased One Pass Retention. It had been found that when cationic starch used as a surface sizing agent, more starch was retained on or near the surface of the sheet than with conventional oxidized starches. Thus surface strengths and quality were improved. In addition it is possible to maintain the desired level of starch penetration into the fiber net and improve porosity, opacity and brightness. In contrast, in most cases, dusting problems are notably eliminated. Cationic surface sized starch improved black and color ink-jet print quality in terms of feathering and optical density of the print image. These improved properties were believed to be due to a combination of fiber bonding and surface orientation more uniform starch concentration on the paper surface was resulted. Moreover cationic charges in the paper surface lend themselves excellently to fix ink jet ink anionic in nature.

• Membrane Journal
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• v.9 no.4
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• pp.209-214
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• 1999

The purpose of this research was to investigate the permeation properties of each stage in three stage reverse osmosis system for cold-mill wastewater reuse. After construction of the three staged pilot plant which had 75% recovery and equipped with seven plate-and-frame modules, the change of each stage's penneate flow and quality were investigated in the process of membrane fouling. The order of average permeate flow was first, second, and third stage at the beginning. As the operation time passed, the permeate flow of first stage was decreased, the second stage was maintained steadily, and the third stage was increased. Accordingly, the fouling was initiated at the first stage and then progressed to the second and third stage. The first stage's permeate quality showed the best and the second and third stage was the next in that order. And the order of quality was maintained during the test periods. Therefore, the permeate quality was not affected by membrane fouling.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.1
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• pp.61-68
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• 2017

The key quality attributes of the pressed powder, one of base makeup products, are skin-affinity and spreadability. In general, there was a limit to meet skin-affinity and spreadability simultaneously, which are opposite attributes each other. In this study, air jet mill process was tried to satisfy two main properties. Skin-affinity was improved by a wet coating of sericite with a mixture of lauroyl lysine (LL) and sodium cocoyl glutamate (SCG). The application of mono-dispersed polymethyl methacrylate (PMMA) and diphenyl dimethicone/vinyl diphenyl dimethicone/silsesquioxane crosspolymer (DDVDDSC) improved both qualities. Air jet mill process has been mainly applied in the pharmaceutical and food industries, and is a method used for processing powder materials in cosmetic field. In this study, we were able to complete makeup cosmetics with an optimum particle size $6.8{\mu}m$ by combining the air jet mill process at the manufacturing stage. It was confirmed that the Ti element was uniformly distributed throughout the cosmetics by EDS mapping, and that the corners of the tabular grains were rounded by SEM analysis. It is considered that this can provide an effect of improving the spreadability when the cosmetic is applied to the skin by using a makeup tool. LL with excellent skin compatibility and SCG derived from coconut with little skin irritation were wet coated to further enhance the adhesion of sericite. SEM images were analyzed to evaluate effect of the dispersion and uniformity of PMMA on spreadability. With the spherical shapes of similar size, it was found that the spreading effect was further increased when the distribution was homogeneously mono-dispersed. The dispersion and spreadability of PMMA were confirmed by measuring the kinetic friction and optimal content was determined. The silicone rubber powder, DDVDDSC, was confirmed by evaluating the hardness, spreading value, and drop test. Finally, it was found that the dispersion of PMMA and silicone rubber powder affected spreadability. Such makeup cosmetics have excellent stability in drop test while having appropriate hardness, and good stability over time. Taken together, it is concluded that air jet mill process can be utilized as a method to improve skin-affinity and spreadability of the pressed powder.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.4
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• pp.271-279
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• 2016

The objective of this study was to determine the effect of the moisture content and pellet mill type on the physical and chemical characteristics of Italian ryegrass (IRG) pellet. Moisture content of raw material significantly (p<0.05) affected IRG pellet formation. Moisture content at 25% was the best condition for IRG pellet formation in terms of shape, power load and temperature changes. The hardness of pellet was decreased when moisture content was increase. However, the hardness of pellet was not affected by pellet mill type. Moisture content at 30% dramatically (p<0.05) decreased the durability compared to moisture content at 25%. Dry matter content of IRG pellet was increased (p<0.05) after pelleting. Total count of microorganism was decreased in pellet due to pressure heat and moisture losses during the pelleting process. These results indicated that the proper moisture content of Italian ryegrass pelleting would be at 25%. In addition, Roll & flat die type would be more suitable than Ring die and Die & flat die type in IRG pelleting. Pelleting works would be beneficial for improving forage quality and long storage.

• Journal of Information Technology Services
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• v.10 no.2
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• pp.177-188
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• 2011

This paper proposes a DEA model for the performance evaluation of each brand of coking coals in an integrated steel mill. The performance is defined as the efficiency which is the ratio of two linear combinations of the output factors to the input factors. There is only one input factor considered in the model : unit price of each brand based on CIF. Five output factors are chosen in consideration of their impact to the quality of cokes such as Ash, VM, LMF, TD, and Rm. Some of the output factors are treated as undesirable in DEA model because the quality criteria are given by the range. The CCR and BCC efficiencies are derived by the DEA model, and the scale efficiency is calculated, too. Each brand of coking coal is classified into four categories according to the CCR and BCC efficiencies, and the most inferior brands are identified as a result. The impact of the input and output factors to the efficiency is analyzed using a multiple regression, then the unit price is revealed as the most critical among them. Also, ANOVA results show that there exist efficiency differences among the coal types and the countries imported, respectively. Finally, the quantitative projection for the inefficient brands is performed if they are to be efficient. The result could be utilized in selecting the good or bad brands of coking coal based on the efficiency in an integrated steel mill. Also, this model will be used to assess the relative efficiency of a new brand of coking coal if it is a candidate to be imported.

• Journal of the Korean Magnetics Society
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• v.15 no.3
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• pp.191-197
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• 2005

In the fabrication process of Fe-based amorphous alloy powder cores by pulverization of the melt-spun ribbons and cold compaction, the effects of powder preparation method on the magnetic & electric properties, powder shapes and microstructure of cores have been investigated. The powder cores made by using rotor mill showed low effective permeability as compared to the cores prepared by ball milling. However the frequency dependence and quality factor properties were superior in the case of rotor-milling. Further the powders prepared by rotor mill had homogeneous and round shapes through strong shearing in the sieve ring, while the ball milled powders were inhomogeneous and relatively small. The lower permeability of the powder cores fabricated with rotor mill was considered to be due to the high internal stress occurred by very intensive shearing. Moreover the powder cores produced by rotor-milling showed lower core loss and good frequency dependence of effective permeability possibly due to the higher electrical insulation between magnetic particles. The dc bias property of the powder cores made by rotor-milling was better than the one by ball-milling.

• Korean journal of food and cookery science
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• v.25 no.1
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• pp.106-118
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• 2009

This study was to investigated optimum preparation conditions for Gugija Heukimja jook by response surface methodology (RSM). The important materials used for the Gugija Heukimja product were Lycium chinese, Seasamum indicum L., Ziziphus jujuba Mill. and rice. Moisture content, crude protein, crude fat, crude ash and crude fiber content were 15.62, 16.60, 13.62, 4.93 and 11.17% for Lycium chinese, 3.62, 20.94, 43.56, 5.67 and 10.72% for Seasamum indicum L., 24.12, 5.38, 0.73, 2.30 and 1.25% for Ziziphus jujuba Mill., and 12.36, 6.98, 0.46, 0.43 and 0.41% for rice, respectively. Optimal extraction conditions of brix, color, pH and total acidity in the materials for Gugija Heukimja jook were temperature $80^{\circ}C$, water volume 850 mL and extraction time of 63 min. The spreadability of jook with Lycium chinese and Ziziphus jujuba Mill. extracts was the highest when black sesame was 12 g pH was the lowest when black sesame was 9 g. PH showed a significant difference when the added black sesame ratio changed. The 'value L' of chromaticity was lower with an increase of the black sesame ratio, 'value a' was higher with an increase of the black sesame ratio, 'value b' was lower with an increase of the black sesame ratio. Brix was lower when black sesame in jook was added. Total acidity was highest (7.27%) when black sesame was 12 g. The degree of gelatinization tended to be lower with additional black sesame. Higher scores of sensory evaluation were found for the product containing 9 g black sesame with Lycii furctus and Ziziphus jujuba Mill. extracts ompared to the other samples with 3 and 6g. No significant difference in taste occurred for Gugija Heukimja jook prepared with over 9 g black sesame, while a great difference showed in color, pH and total acid. Therefore, the Gugija Heukimja jook prepared under the optimal conditions of 9 g black sesame with Lycium chinese and Ziziphus jujuba Mill. extracts exhibited higher qualities. Gugija Heukimja jook can use the easier for Yacksun jook. It is expected to become functional in the product's development.

• Journal of Biosystems Engineering
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• v.34 no.3
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• pp.155-160
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• 2009

This study was attempted to quality characteristics of ginseng powder using molecular press dehydration(MD) method. Ginseng powder was dried using maltodextrin as dehydrating agents, and the quality of the ginseng powder was compared with that of freeze-drying and hot air-drying samples in terms of colors, moisture contents and grain size. The colors of ginseng powder using MD-drying and freeze-drying was better than hot air-dried ginseng powder. The moisture contents of ginseng powder using MD-drying was 9.49%, while freeze-drying was 4.14% and hot air-drying 11.71% after 72ball mill times. The grain size of ginseng powder using MD-drying and freeze-drying was better than hot air-drying ginseng powder. These results suggest that drying of ginseng powder using molecular press dehydration method is very efficient, because minimal cell destruction may be achieved.