• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.23-29
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• 2016

Effects of cationic polyvinylamine (PVAm) dry strength agent on effectiveness of optical brightening agent (OBA) during fine papermaking and the mechanism for brightness reduction of paper by PVAm was investigated by UV/Vis spectroscopy and turbidity measurement of OBA solution with PVAm. It was shown that PVAm reduced brightness of paper while opacity was not varied and tensile strength of paper was increased. Tetra-type OBA solution showed the peaks around the wavelength of 280 nm and 330 nm and the increase in the OBA concentration increased the UV absorbance in all wavelength. Addition of PVAm into the OBA solution decreased the UV absorbance at 280 nm. Turbidities of OBA and PVAm solutions were close to zero, respectively, while the turbidity value increased for the mixed solution of OBA and PVAm in various mixing ratios and the highest value was obtained when the mixing ratio of PVAm and OBA was 5:5, meaning that cationic PVAm formed complex with anionic OBA. In conclusion, cationic PVAm could form a complex with anionic OBA and that reduced UV absorbance, resulting in the reduced brightness of paper.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.1
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• pp.99-112
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• 1997

Mixing process of impinging jets of liquid oxidizer and liquid fuel is simulated by using water and sodium carbonate (Na$_{2}$CO$_{3}$) solution. The shapes of liquid sheets are visualized and flowrate distributions are measured by collecting droplets using measuring cells. Mixing charateristics are studied by using acid-base titration. Stable liquid sheets are formed and two liquid jets are well mixed for symmetric impinging jets. Similarity in flowrate distribution for various measuring heights is observed. For asymmetric impinging jets, liquid sheets become unstable as the difference in the velocities of jets increases. In some extreme cases, liquid sheets are not formed and the jets are separated. Dimensionless variables are adopted demonstrating similarly in flowrate distribution. Mixing characteristics vary significantly with experiment conditions.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.93-96
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• 2005

High temperature furnace such as Steam power plant and incinerator contribute considerable part of NOx generation and face urgent demand of De-NOx system. Reducing agents are necessary to use De-NOx system. In this study mixing caused by direct injection of reducing agent solution spray into flue gas duct was measured. Carbonated water was used as tracer and simulated agent because ammonia as a reducing agent is not proper to experiment. Mixing and evaporation must occur simultaneously and quickly enough to achieve desirable efficiency. To achieve that, the angle of attack of static mixer and the location is simulated and $CO_2$ concentration is measured.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.751-756
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• 2001

An experimental model of the advanced mixing control in the parallel supersonic-subsonic mixing jet (M$_1$=1.78 and M$_2$=0.30) is numerically simulated. An oscillating wall boundary condition is used as the modeling of a wall cavity for mixing enhancement. The obtained pitot pressure distributions along cross sections at the developing region of the turbulent jets are validated from the good agreement with equivalent experimental data. The similarity solution of dimensional analysis also coincides with this numerical result at the self-similar region sufficiently far from the jet exit.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.154-155
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• 2017

With the recent development in construction industry, industrial by-products fly ash(FA) and blast furnace slag(BS) have been used in large quantities as an alternative to cement, as a solution for environmental problems and resource exhaustion. This study analyzed the basic characteristics according to the changes in replacement ratio and mixing ratio of FA and BS in high strength SCMs concrete, from which in turn it sought to find the optimal mixing ratio for high strength concrete The results showed that in unhardened concrete the more the replacement ratio and FA mixing ratio increases the slump flow will increase while amount of air decreases, and setting time is delayed. In hardened concrete the more the replacement ratio and FA mixing ratio increases the more the overall compression strength decreases, but until 28 days of material age the larger of the BS ratio displayed the best compression strength.

• Journal of the Korean Society of Visualization
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• v.16 no.2
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• pp.53-58
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• 2018

This paper presents an electromagnetically driven microrobot for the enhancement of mixing performance in high viscous liquid media such as blood and bone marrow. First, an electromagnetic system was fabricated, and the magnetic flux density generated from the system was compared with the theoretical value. Second, the reciprocating motion of the microrobot was demonstrated in microchannel using electromagnetic system. As a proof of concept, the mixing performance by the electromagnetically driven microrobot in high viscous liquid was investigated using safranin solution. As a result, it was completely mixed within 140 s with the reciprocating motion of the microrobot while it took 1680 s for natural diffusion. In addition, the mixing efficiency was quantitatively evaluated through a mixing index obtained by an image analysis. The proposed method provides not only wireless actuation of a microrobot with a simple design but also high mixing performance in variety of high viscous liquid media.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.247-252
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• 2011

Electrical conductivity, drainage, and irrigation amount of nutrient solution are important factors for determination of the mixing ratio of fresh and reused nutrient solutions in closed-loop soilless culture. Generally a fixed mixing ratio is applied in commercial scale greenhouses using solar radiation-based irrigation system. Although it ensures continuous supply of fresh nutrient solution in the mixing process, occasional discharge of the drainage is inevitably required. This study was conducted to compare the nutrient replenishing effect under different mixing processes and to investigate appropriate mixing process. For this experiment, a fixed mixing ratio (FR), modifiable mixing ratio (MR), and open-loop (OP) as control were applied. Mixing ratio was determined by a set value of EC for dilution of collected drainage in FR and the set values of 1.0 and $2.0dS{\cdot}m^{-1}$ were used as treatments (FR 1.0 and FR 2.0), respectively. In MR, mixing ratio was determined based on EC and volume of drainage within irrigation volume per event. The volume of drainage stored in the drainage tank tended to increase in FR 1.0. Although such trend was not observed in FR 2.0 and MR, the volume of drainage stored in MR was lower than that in FR 2.0. The ion balance of $Mg^{2+}:K^+:Ca^{2+}$ or $SO^{2-}_4:NO^-_3:PO^{3-}_4$ in the drainage and reused nutrient solution changed within a narrow range regardless of treatment.

• YAKHAK HOEJI
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• v.20 no.1
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• pp.41-43
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• 1976

The dissociation constant of phenol red indicator in mixed solvents was studied. Methanol and ethanol were employed as solvents and studied the changes of pK values of indicator according to the kind and concentration of organic solvent which is mixed into water solution. The effect of methanol solvent on pK is negligible at 40%, 60% and 80% mixing. While in the case of ethanol, the effect of above 40% mixing is not negligible.

• Elastomers and Composites
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• v.27 no.4
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• pp.262-266
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• 1992

A number of tin-containing elastomers are produced commercially by Korea Kumho Petrochemical Co., Ltd. (KKPC) under the Kosyn Sol tradename. The effect of mastication of commercial and laboratory polymerized S-SBR has, been investigated using chemical mixer(ML-500), NMR, GPC and Mooney viscometer. Mastication of polymers containings coupling bonds is affected by the amount of stearic acid, the temperature of mixing and the time length of mixing.

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.312-317
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• 2007

Performing random number simulations, we approximated that the distribution of the number of ways for arranging molecules randomly on a lattice is a normal distributon for N12, the number of interactions between the nearest neighbors of different molecules. From this distribution, an approximate equation of the excess Gibbs energy GE for a lattice solution of nonrandom mixing was derived. Using the equation, liquid-vapor equilibria of several binary solutions were calculated and compared with the calculated result of other equations.