• Journal of the Society of Cosmetic Scientists of Korea
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• v.10 no.1
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• pp.24-41
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• 1984

Tallow fatty acid consists of mixtures of fatty acids differing in chain length and saturation. In separation of tallow fatty acid, the effects of the type and concentration of detergents and electrolytes were studied. And the changes of acid composition of particular fractions were determined by gas-chromatography. Sodium lauryl sulfate (SLS), sodium lauryl ether sulfate (SLES) and sodium lauryl benzene sulfonate (SLBS) were used as detergents and NaCl, Na2SO4 and MgSO4 were used as electrolytes. At low concentration of detergent, the tallow fatty acid was not fully wetted, and at high concentration, the emulsion was so stable that the tallow fatty acid was not well separated. The addition of proper amount of electrolyte increased the separation efficiency by the decrease of interfacial tension and by the increase of the amount of adsorbed detergent on the surface of solid fatty acid crystals. The optimum range of detergent was 0.4-0.6% (wt.) in SLS, 0.2-0.4% in SLES and 2.0-) .0% in SLBS. And the optimum range of electrolyte was 2.0-2.5% in NaCl, 3.0-4.0% In Na2SO4 and 0.5-1.0% in MgSO4 respectively.

• Archives of Pharmacal Research
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• v.23 no.5
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• pp.441-445
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• 2000

Achiral-chiral column switching HPLC assay was developed to allow the separation and quantification of the enantiomers of terbutaline in human plasma by means of fluorescence detection. Plasma samples were prepared by solid-phase extraction with sep-pak silica, followed by HPLC assay. The enantiomers of terbutaline and the internal standard were separated from the biological matrix on a silica column, and the two enantiomers were resolved and quantified on a Sumichiral OA-4900 column. The two columns were connected by a switching valve equipped with silica trap column, The trap column was used to concentrate the terbutaline in the eluent from the achiral column before back flushing onto the chiral phase. For each enantiomers, the assay was linear between 2.5-125 ng/$m\ell$ (r=0.9999) and detection limit was 1.0 ng/$m\ell$ .

• Korean Journal of Computational Design and Engineering
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• v.15 no.1
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• pp.33-42
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• 2010

In this study, new medial surface calculation methods using Voronoi diagrams are investigated for the point samples extracted on closed surface models. The medial surface is defined by the closure of all points having more than one closest point on the shape boundary. It is a one of essential geometric information in 3D and can be used in many areas such as 3D shape analysis, dimension reduction, freeform shape deformation, image processing, computer vision, FEM analysis, etc. In industrial parts, the idealized solid parts and shell shapes including sharp edges and vertices are frequently used. Other medial surface extraction methods using Voronoi diagram have inherent separation and branch problems, so that they are not appropriate to the sharp edged objects and have difficulties to be applied to industrial parts. In addition, the branched surfaces on sharp edges in shell shapes should be eliminated to obtain representative medial shapes. In order to avoid separation and branch problems, the new approach by analyzing the shapes and specially sampling on surfaces has been developed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.225-228
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• 2010

In this paper, the present status of research, development, and required technologies for the thermal barrier type dual-pulse rocket motor of the advanced countries was analysed. The result of the conceptual design of the forward or backward ignition systems was also demonstrated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.04a
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• pp.15-15
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• 1998

The problem of the impingement of a sonic or a supersonic jet on a flat surface has not only wide applications but has also interesting and very complex flow phenomena. The main applications of this impinging jet include prediction of solid surface erosion, design of launcher systems, stage separation of multi-stage rocket system, V/STOL operations, thermal spray system, and manufacturing technologies of materials. Much have been learned about the supersonic impinging jet flow field but many fundamental questions have not been answered satisfactorily. The problem encompasses many facets of fluid dynamics which, in combination, present the compressibility effect and the viscous-inviscid interaction, coupled with flow separation and reattachment. What is more, there are many flow parameters that have on the impinging jet flow field, for example, Mach number, Reynolds number, pressure ratio, distance between the nozzle exit and flat plate, jet shock structure, nozzle diameter and etc. Thus the existing data on the supersonic impinging jet flow present considerable disagreement in which quantitative comparison between one result and another is often impossible.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.379-382
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• 2017

Flow characteristics of dual bell nozzle with pintle were investigated. Thrust and thrust coefficient were compared with the pintle-bell nozzle of the same condition, and difference according to the pintle stroke was investigated. At stroke 0 mm, the thrust of the dual bell nozzle was about 13.18% higher than the bell nozzle, and when the pintle was backward, it was similar to the bell nozzle. The change in expansion ratio with stroke was considered to be more advantageous for a dual bell nozzle that performs altitude compensation through separation and transition.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.47-50
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• 2003

Carbon-silica membranes were Prepared by Pyrolyzing polyimide/silica composite obtained from ill-situ polymerization of alkoxy silanes via sol-gel reaction. In this study, effects of silica content and silica network in polyimide matrix were focused on the gas permeation and separation properties of the final carbon-silica membrane. The membranes prepared were characterized with a field emission scanning electron microscopy (FE-SEM), a solid state $^{29}$ Si nuclear magnetic resonance spectroscopy ($^{29}$ Si-NMR), an electron spectroscopy for chemical analysis (ESCA), a thermogravimetric analysis (TGA) and gas permeation tests.

• Membrane Journal
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• v.4 no.2
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• pp.85-95
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• 1994

This papr studies the dynamic effects of polyelectrolyte in the multilayered membrane. It is found that electrophoretic convection in the fluid phase can be used to accelerate the speed of the polyelectrolyte. The model in the membrane separation is studied via interactions between fluid and solid phases. The spectra evaluation using the operator theoretic method is performed for the parametric studies of the physical properties in the membrane process. The findings of this paper shoould be useful in guiding the design of separation devices. This paper shows one example for macroscopic study the theoretical review paper of membrane transport.

• Journal of Environmental Science International
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• v.15 no.1
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• pp.77-84
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• 2006

An effective technique of sludge separation is required for excess sludge of sewage or wastewater plant. The separation of bulking sludge of paper manufacturing plant was studied using DAF(Dissolved Air Flotation) system. The effects of parameters such as nozzle type, A/S(air/solid) ratio. pressure, injection time of pressured water and saturation time were examined. The results showed that the best nozzle type was flat which had small orifice hole, The optimum A/S ratio and pressure were $7.070\times10^{-3}$(recycle ratio of pressured water $20\%$) and 5atm, respectively. Injection times of pressurized water around 20-25 sesc and flotation time of 30 min appeared to be optimal for the DAF operation. The order of performance of packing was 18 mm > 22 mm > 32 mm.

• Progress in Superconductivity and Cryogenics
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• v.23 no.3
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• pp.20-25
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• 2021

Milking parlor wastewater contains high concentration suspended solid (SS), nitrogen, and/or phosphate as well as organic compounds. A new biological wastewater process by magnetic separation, magnetic activated sludge (MAS) process, was applied to milking parlor wastewater treatment process. A three step wastewater treatment process of coagulation sedimentation / ammonia stripping (C/S), magnetic activated sludge process and contact oxidation (CO) was proposed for removal of these pollutants. First step, C/S process recovered 96% TN and 96% PO₄^3--P as resource for fertilizer from the wastewater. 81% biochemical oxygen demand (BOD) in wastewater was removed after MAS process. As a results, all pollutant concentrations satisfied Japanese effluent standards. Most of residual BOD and SS were removed by the CO process. It was estimated that the proposed process could reduce the process space to 1/7.