• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.426-431
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• 2010

68% of the manufacturing costs of solar cell wafer can be attributed to the slurry. The recycling of slurries is mandatory for reducing the costs of manufacturing wafering production, and the disposal of industrial waste, as well as for cutting down pollution levels. Slurries are currently being recycled using the centrifuge(decanter) method. However, this method is less than optimal as it does not completely remove the fine particles, leading to low quality. Also, be cause of the incomplete separation from the oil, it causes the impurities in the dried slurries. This study aims to develope a new recycling technology that overcomes the flaws of the centrifuge by utilizing chemicals. It will provide a total solution to the crucial process of recycling slurries in the making of solar cell wafer, by increasing the efficiency and renewable rate.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.789-795
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• 2014

Acetic acid is the most abundant and serious ethanol fermentation inhibitor in dilute-acid hemicellulosic hydrolysates. A mixture of xylose, acetic acid and sulfuric acid was chosen as a simulated hemicellulosic hydrolysate so as to find an optimal separation system to selectively remove acetic acid from the hydrolysates. In order to attain the purpose, emulsion liquid membrane was applied to removal of acetic acid from the simulated hemicellulosic hydrolysate. The effects of main constituents of water-in-oil (W/O) emulsion, such as amine extractant type, surfactant composition, additive type, and type and concentration of stripping agent, on extraction of acetic acid, xylose, and sulfuric acid in the simulated hemicellulosic hydrolysate were investigated. Under specific experimental conditions, degree of extraction of acetic acid was higher than 95% while loss of xylose was insignificant, which means that the current emulsion liquid membrane can be an economically feasible process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.549-552
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• 2004

A simple, efficient and accurate method was developed for the simultaneous determination of non-permitted oil soluble colorants (sudan I, II, III and IV) in foods. The identification has been carried out for sudan colorants by TLC as well as HPLC with photodiode array (PDA) detection. Separation of sudan colorants was achieved within 20 min by a gradient elution with water and acetonitrile as eluents. Sudan colorants showed good linear relationships in the range of 0.1 ～ 100 $\mu\textrm{g}$/mL. The correlation coefficients of the calibration curve for sudan colorants exceeded 0.999. The detection limits (signal-to-noise ratio 3 : 1) for sudan I, II, III and IV were 0.01, 0.01, 0.02 and 0.02 $\mu\textrm{g}$/mL, respectively. This method has been successfully applied to the analysis of red pepper powder, Kimchi and Kakdugi, and the average recoveries for real samples ranged from 83.02% to 104.3%.

• Applied Biological Chemistry
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• v.23 no.1
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• pp.14-22
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• 1980

White and black sesame produced in Korea were defatted with ethyl ether or n-hexane. Defatted sesame meal was extracted with water and salt solution, and protein extraction was precipitated at various pH 1 through 12, with trichloro acetic acid (TCA), tannic acid and ammonium sulfate, respectively. Protein was purified by Sephadex A-25, G-75, G-100 and G-200, and identified its protein fraction by polyacrylamide gel electrophoresis. Amino acids composition of protein in white sesame was analyzed by automatic amino acid analyzer. Protein contents of white sesame, black sesame and sesame meal are 20.5%, 19.2%, and 44.7%, respectively. n-Hexane was the most suitable solvent for extraction of oil from sesame. Crude protein precipitation was better in higher pH. The protein extraction was more effective with the solution containing sodium chloride tinder the pH 8. Globulin in total protein was high and prolamin was less than in other cereal proteins. Glutamic acid contents of white sesame and sesame globulin were 17.1%, and 20%, respectively. Both proteins contained relatively high levels of essential amino acids. 12-13 bands were found in water soluble protein and 2 bands in salt soluble protein were detected by the disc gel electrophoresis, and were identified in both of white and black sesame. The salt soluble protein of white sesame could be purified by Sephadee G-100 and G-200.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.1
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• pp.75-89
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• 2009

The purpose of this study was to identify $PM_{2.5}$ sources and to estimate their contributions to the border of Yongin-Suwon area, based on the analysis of the $PM_{2.5}$ mass concentration and the associated inorganic elements, ions and carbon components. The contribution of $PM_{2.5}$ sources were estimated by using a positive matrix factorization (PMF) model to identify air emission sources. For this study, $PM_{2.5}$ samples were collected from May, 2007 to April, 2008. The inorganic elements were analyzed by an ICP-AES. The ionic components in $PM_{2.5}$ were analyzed by an Ie. The carbon components were also analyzed by DRI/OGC analyzer. After performing PMF modeling, a total of 12 sources were identified and their contributions were quantitatively estimated. The contributions from each emission source were as follows: 11.3% from oil combustion source, 3.4% from bus/highway source, 5.8% from diesel vehicle source, 4.7% from gasoline vehicle source, 8.8% from biomass burning source, 15.1 % from secondary sulfate, 5.2% from secondary nitrate source, 13.4% from industrial related source, 4.1% from Cl-rich source, 19.6% from soil related source, 1.0% from aged sea salt, and 7.4% from coal combustion source, respectively. This study provides basic information on the major sources affecting air quality, and then it will help to effectively control $PM_{2.5}$ in this study area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.4 s.27
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• pp.267-272
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• 2006

Butterfly valves have been used for shut-off and throttling-control application in many industrial fields. Recently, they are frequently used for cooling water, oil system and ballast piping system of many larger vessels. They are especially suited for flow throttling control of heat exchangers in engine room. Measurement by the PIV(Particle Image Velocimetry) was conducted to investigate the flow characteristics of butterfly valve inserted within circular pipe. Flow behaviors such as instantaneous and time-mean velocity vectors are investigated. Furthermore, to reveal systematic performance of the butterfly valve, wall pressure was measured at 6 points along the pipe by digital manometer. As the valve position moves to the closed side, flow separation increases and persists its tendency downstream until smoothly uniform flow developed. The pressure loss is found to be about zero for the disk open angles less than 45 degrees, but is substantially increased for those larger than 60 degrees.

• Journal of Technologic Dentistry
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• v.27 no.1
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• pp.89-95
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• 2005

In the manufacture of ceramo-metal crown, difference of fracture strength according to the metal depth has been known to be an important influence on enough intensity and internal stress to endure an occlusion-pressure as well as aesthetics of rehabilitating similar colour such as natural teeth. Depth of ceramic material could be determined by that of metal in three groups: first case of thin depth, second case of thick depth, and third case of constant depth. For the enhancement of the fracture strength between metal and ceramic materials and aesthetic satisfaction, a study on the bonding force, fracture strength, and aesthetics have been required more. In this study, therefore metal coping were made in three groups of A, B and C by using both ceramic powder of Norithe and metal of Columbium, which have been used primarily in the market. A group was made in $0.2mm\times10mm\times10mm$, B group was made in $0.4mm\times10mm\times10mm$, and, C group was made in $0.8mm\times10mm\times10mm$, respectively. The number of metal coping in each group was 10, and total sample numbers used in this study were 30 metal copings. After these metal coping tissue were in the process of build-up in 1.5mm constant depth of porcelain, firing, and glazing, the fracture strength about each metal coping tissue was investigated using oil press. It was found that the average values of durable occlusion pressure for separation of ceramic material in the porcelain fused to metal crown (PFM) in the each group showed the increasing order of A group (30 bar), B group (42 bar), and C group (44 bar), respectively. Proper depth of metal coping in the PFM was considered to be 0.4mm in the B group because this metal size showed higher durable property to the occlusion pressure and better coupling strength in the ceramo-metal crown.

• Journal of the Korean GEO-environmental Society
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• v.11 no.8
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• pp.25-32
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• 2010

Contamination of soil and groundwater by the compounds of hydrocarbon petroleum has been widely accepted as the main cause that harms the environments and health. To remove those pollutants, absorbing clothes, activated carbons, or oil-water separation devices with the gravity method are employed for treatment. However, those materials and devices cannot remove the emulsion pollutants despite of their efficiency for removing free products. Therefore, we investigated the problems which occur during the groundwater treatment for the highly concentrated suspended solid particles, which can be resulted from excavation, and to propose methods to remove TPH(Total Petroleum Hydrocarbon). After coagulation experiment with high molecular polymers, the concentration of SS(Suspended Solids) and COD(Chemical Oxygen Demand) turned to satisfy the groundwater quality criteria within 5 minutes while the concentration of TPH failed to meet the water quality standard of effluent. Consequently, the water quality criteria for effluent could not be met by single DAF(Dissolved Air Flotation) process. However all water quality criteria could be satisfied after 20 minutes when coagulation reactions are carried out simultaneously in the DAF reactor.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.122-128
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• 2012

The influences of fluorescence, scattering, and flocculation in turbid material by light scattering of L-aspartic acid, preservative and emulsifier were interpreted for the scattered fluorescence intensity and wavelength. They have been studied the molecular properties by the spectroscopy of laser induced fluorescence (LIF) and flocculation. The effects of optical properties in scattering media have been found by the optical parameters(${\mu}_s$, ${\mu}_a$, ${\mu}_t$). Flocculation is an important step in many solid-liquid separation processes and is widely used. When two particles approach each other, interactions of several colloid particles can come into play which may have major effect on the flocculation and LIF process. The values of scattering coefficient ${\mu}_s$ are large by means of the increasing scattering of scatterer, The values have been found that the slope decays exponentially as a function of concentration from laser source to detector by our experimental result. It may also aid in designing the best model for oil chemistry, bio-pharmaceutical products, laser medicine and application of medical engineering on LIF and coagulation in particle transport mode.

• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.179-184
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• 2008

The separation and purification of succinate are necessary for the succinic acid production by a fermentation process. Among the purification processes, desalination of succinate is inevitable. In this work, electrodialysis was selected as a desalination method and its operating parameters affecting the degree of desalination and energy consumption were examined. Commercialized electrodialysis apparatus was used in this work and its optimum operating parameters were determined by using design of experiment (DOE) method. Voltage, concentration of succinate, and pH were selected as main parameters. Among them, voltage seemed to be the most important one. The final conversion of succinate to succinic acid was calculated when the operating parameters were optimized. Finally, the effect of impurities, such as corn steep oil, yeast extract, and dextrose on the electrodialysis efficiency was also studied.