The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Woo-sik Kim - One of the best experts on this subject based on the ideXlab platform.
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Cocrystallization of Caffeine–Maleic Acid in a Batchelor Vortex Flow
Crystal Growth & Design, 2020Co-Authors: Tu Lee, Woo-sik KimAbstract:Here, the influence of Batchelor Vortex Flow on the cocrystallization of caffeine (CAF) and maleic acid (MA) is studied and compared with that of turbulent eddy Flow. Batchelor Flow, induced in a r...
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cocrystallization of caffeine maleic acid in a batchelor Vortex Flow
Crystal Growth & Design, 2020Co-Authors: Tu Lee, Woo-sik KimAbstract:Here, the influence of Batchelor Vortex Flow on the cocrystallization of caffeine (CAF) and maleic acid (MA) is studied and compared with that of turbulent eddy Flow. Batchelor Flow, induced in a r...
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Polymorphic Crystallization of Sulfamerazine in Taylor Vortex Flow: Polymorphic Nucleation and Phase Transformation
Crystal Growth & Design, 2015Co-Authors: Sun-ah Park, Sun Lee, Woo-sik KimAbstract:The influence of a periodic Taylor Vortex Flow on the polymorphic crystallization of sulfamerazine (SMZ), including polymorphic nucleation and phase transformation, was investigated using a Couette–Taylor (CT) crystallizer, and also compared with the influence of a random turbulent Flow in a mixing tank (MT) crystallizer. In the MT crystallizer, the induction of the metastable phase (form-I) occurred first, which was then followed by the induction of the stable phase (form-II) 10–85 h later. However, this whole process was significantly reduced to a half hour in the CT crystallizer, demonstrating the high efficiency of a Taylor Vortex Flow for the induction of polymorphic nucleation. The efficiency of the Taylor Vortex Flow was also enhanced when increasing the rotation speed. As a result, the stable and metastable phases were simultaneously nucleated at the first induction with a rotation speed above 300 rpm; plus the stable-phase fraction nucleated at the first induction increased when increasing the ro...
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Polymorphic Crystallization of Sulfamerazine in Taylor Vortex Flow: Polymorphic Nucleation and Phase Transformation
2015Co-Authors: Sun-ah Park, Sun Lee, Woo-sik KimAbstract:The influence of a periodic Taylor Vortex Flow on the polymorphic crystallization of sulfamerazine (SMZ), including polymorphic nucleation and phase transformation, was investigated using a Couette–Taylor (CT) crystallizer, and also compared with the influence of a random turbulent Flow in a mixing tank (MT) crystallizer. In the MT crystallizer, the induction of the metastable phase (form-I) occurred first, which was then followed by the induction of the stable phase (form-II) 10–85 h later. However, this whole process was significantly reduced to a half hour in the CT crystallizer, demonstrating the high efficiency of a Taylor Vortex Flow for the induction of polymorphic nucleation. The efficiency of the Taylor Vortex Flow was also enhanced when increasing the rotation speed. As a result, the stable and metastable phases were simultaneously nucleated at the first induction with a rotation speed above 300 rpm; plus the stable-phase fraction nucleated at the first induction increased when increasing the rotation speed. In addition, the polymorphic nucleation was facilitated when decreasing the dimension of the Taylor Vortex Flow, which was proportional to the gap size between the inner and outer cylinders. The periodic Taylor Vortex Flow was also more effective than the random turbulent Flow for the phase transformation from the metastable phase to the stable phase. Thus, the time period for the complete phase transformation (called the reconstruction time) in the CT crystallizer was 5–10 times shorter than that in the MT crystallizer. Furthermore, the phase transformation was enhanced when decreasing the dimension of the Taylor Vortex due to the promotion of the mass transfer. Finally, the polymorphic nucleation and phase transformation that varied with the rotation speed and gap size of the CT crystallizer were linearly correlated with one parameter: the viscous energy dissipation, representing the hydrodynamic intensity of the Taylor Vortex Flow
Sun-ah Park - One of the best experts on this subject based on the ideXlab platform.
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Polymorphic Crystallization of Sulfamerazine in Taylor Vortex Flow: Polymorphic Nucleation and Phase Transformation
Crystal Growth & Design, 2015Co-Authors: Sun-ah Park, Sun Lee, Woo-sik KimAbstract:The influence of a periodic Taylor Vortex Flow on the polymorphic crystallization of sulfamerazine (SMZ), including polymorphic nucleation and phase transformation, was investigated using a Couette–Taylor (CT) crystallizer, and also compared with the influence of a random turbulent Flow in a mixing tank (MT) crystallizer. In the MT crystallizer, the induction of the metastable phase (form-I) occurred first, which was then followed by the induction of the stable phase (form-II) 10–85 h later. However, this whole process was significantly reduced to a half hour in the CT crystallizer, demonstrating the high efficiency of a Taylor Vortex Flow for the induction of polymorphic nucleation. The efficiency of the Taylor Vortex Flow was also enhanced when increasing the rotation speed. As a result, the stable and metastable phases were simultaneously nucleated at the first induction with a rotation speed above 300 rpm; plus the stable-phase fraction nucleated at the first induction increased when increasing the ro...
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Polymorphic Crystallization of Sulfamerazine in Taylor Vortex Flow: Polymorphic Nucleation and Phase Transformation
2015Co-Authors: Sun-ah Park, Sun Lee, Woo-sik KimAbstract:The influence of a periodic Taylor Vortex Flow on the polymorphic crystallization of sulfamerazine (SMZ), including polymorphic nucleation and phase transformation, was investigated using a Couette–Taylor (CT) crystallizer, and also compared with the influence of a random turbulent Flow in a mixing tank (MT) crystallizer. In the MT crystallizer, the induction of the metastable phase (form-I) occurred first, which was then followed by the induction of the stable phase (form-II) 10–85 h later. However, this whole process was significantly reduced to a half hour in the CT crystallizer, demonstrating the high efficiency of a Taylor Vortex Flow for the induction of polymorphic nucleation. The efficiency of the Taylor Vortex Flow was also enhanced when increasing the rotation speed. As a result, the stable and metastable phases were simultaneously nucleated at the first induction with a rotation speed above 300 rpm; plus the stable-phase fraction nucleated at the first induction increased when increasing the rotation speed. In addition, the polymorphic nucleation was facilitated when decreasing the dimension of the Taylor Vortex Flow, which was proportional to the gap size between the inner and outer cylinders. The periodic Taylor Vortex Flow was also more effective than the random turbulent Flow for the phase transformation from the metastable phase to the stable phase. Thus, the time period for the complete phase transformation (called the reconstruction time) in the CT crystallizer was 5–10 times shorter than that in the MT crystallizer. Furthermore, the phase transformation was enhanced when decreasing the dimension of the Taylor Vortex due to the promotion of the mass transfer. Finally, the polymorphic nucleation and phase transformation that varied with the rotation speed and gap size of the CT crystallizer were linearly correlated with one parameter: the viscous energy dissipation, representing the hydrodynamic intensity of the Taylor Vortex Flow
Kunio Kataoka - One of the best experts on this subject based on the ideXlab platform.
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Effect of Inhomogeneous Mixing on Chemical Reaction in a Taylor Vortex Flow Reactor
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 2002Co-Authors: Naoto Ohmura, Hirokazu Okamoto, Tsukasa Makino, Kunio KataokaAbstract:Effect of inhomogeneous mixing on chemical reactions in a Taylor Vortex Flow reactor was experimentally investigated by using a second-order reaction system. The Flow-visualization experiment by a laser induced fluorescence method was also carried out to observe the cross-sectional view of mixing behavior in the inside of Taylor Vortex cells. In the reaction experiment, the reaction among hydrogen peroxide, iodide ions and hydrogen ions, i.e. 2H+ + 2I– + H2O2 → I2 + 2H2O, was used. The temporal evolution of the concentration of iodine was observed from the temporal variation of color of iodine. The Flow-visualization experiment clearly revealed the existence of two different mixing zones within a Taylor Vortex cell at low Reynolds numbers. Namely, the fluid Flowing near the cell boundary was axially well-mixed, while the fluid element confined to the Vortex core region was poorly exchanged with the outer well-mixed Flow region. This Vortex core region, called an isolated mixing region (IMR), decreased as increasing the Reynolds number. It has been found in the reaction experiment that the reaction rate is larger in laminar and singly-periodic wavy Taylor Vortex Flow regimes than in quasi-periodic and chaotic Taylor Vortex Flow regimes.
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Intercellular mass transfer in wavy/turbulent Taylor Vortex Flow
International Journal of Heat and Fluid Flow, 1998Co-Authors: Naoto Ohmura, Tsukasa Makino, Atsushi Motomura, Yuichiro Shibata, Kunio KataokaAbstract:Abstract Axial mass transfer or mixing through trains of cellular vortices has been observed in the range of time-dependent wavy Vortex Flow with the aid of visualization technique of wave motion, salt-tracer response technique, and spectral analysis of fluctuating velocity-gradients. There appear multiple stable Flow states even at the same Reynolds number owing to the hysteresis of the Flow system, depending upon the start-up operation. Intercellular mass transfer depends upon the axial wavelength and wave motion as well as the Reynolds number in the range of singly (SPWVF) and doubly periodic wavy Vortex Flow (DPWVF) whereas it is controlled mainly by turbulent motion in the range of weakly turbulent wavy Vortex (WTWVF) and fully turbulent Taylor Vortex Flows (TTVF). Intracellular mixing increases monotonically with Reynolds number, regardless of the Flow state.
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Emulsion polymerization of styrene in a continuous Taylor Vortex Flow reactor
Chemical Engineering Science, 1995Co-Authors: Kunio Kataoka, Naoto Ohmura, Masato Kouzu, Yosiharu Simamura, Masayoshi OkuboAbstract:Abstract A continuous emulsion polymerization of styrene was tried in a Taylor Vortex Flow reactor which has characteristics of a plug Flow reactor. The Taylor Vortex Flow reactor has the mixing characteristics appropriate for this reaction system. The steady-state conversion, the average molecular weight and the size distribution of latex particles can be controlled by the Flow condition as well as by the reaction temperature.
Masayoshi Okubo - One of the best experts on this subject based on the ideXlab platform.
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Emulsion polymerization of styrene in a continuous Taylor Vortex Flow reactor
Chemical Engineering Science, 1995Co-Authors: Kunio Kataoka, Naoto Ohmura, Masato Kouzu, Yosiharu Simamura, Masayoshi OkuboAbstract:Abstract A continuous emulsion polymerization of styrene was tried in a Taylor Vortex Flow reactor which has characteristics of a plug Flow reactor. The Taylor Vortex Flow reactor has the mixing characteristics appropriate for this reaction system. The steady-state conversion, the average molecular weight and the size distribution of latex particles can be controlled by the Flow condition as well as by the reaction temperature.
Naoto Ohmura - One of the best experts on this subject based on the ideXlab platform.
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Dispersion of Floating Particles in a Taylor Vortex Flow Reactor
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 2010Co-Authors: Kenjiro Saomoto, Takafumi Horie, Norihisa Kumagai, Teiji Takigawa, Mohamed Nabil Noui-mehidi, Naoto OhmuraAbstract:The present study investigated the dispersion of floating particles in a Taylor Vortex Flow reactor experimentally and numerically. The working fluid was glycerin solution and had a density (ρf) of 1210 kg·m-3 and a viscosity (μ) of 0.1 Pa·s. Floating particles of an acrylic resin had a density (ρp) of 1190 kg·m-3.Two groups of particles with mean diameters of 710 and 974μm were discerned. Although particles penetrated the Taylor Vortex Flow region in the axial direction at different rotational Reynolds numbers, particle segregation was observed. It was confirmed that the smaller particles penetrated deeper in the axial direction. Numerical simulations were also conducted to elucidate the mechanism of particle segregation. Numerical results of a particle-tracking method indicate that the small particles moved on the outermost orbit of a torus. Results of a distinct element method suggest that interparticle collision affected particle transference between vortices.
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Effect of Inhomogeneous Mixing on Chemical Reaction in a Taylor Vortex Flow Reactor
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 2002Co-Authors: Naoto Ohmura, Hirokazu Okamoto, Tsukasa Makino, Kunio KataokaAbstract:Effect of inhomogeneous mixing on chemical reactions in a Taylor Vortex Flow reactor was experimentally investigated by using a second-order reaction system. The Flow-visualization experiment by a laser induced fluorescence method was also carried out to observe the cross-sectional view of mixing behavior in the inside of Taylor Vortex cells. In the reaction experiment, the reaction among hydrogen peroxide, iodide ions and hydrogen ions, i.e. 2H+ + 2I– + H2O2 → I2 + 2H2O, was used. The temporal evolution of the concentration of iodine was observed from the temporal variation of color of iodine. The Flow-visualization experiment clearly revealed the existence of two different mixing zones within a Taylor Vortex cell at low Reynolds numbers. Namely, the fluid Flowing near the cell boundary was axially well-mixed, while the fluid element confined to the Vortex core region was poorly exchanged with the outer well-mixed Flow region. This Vortex core region, called an isolated mixing region (IMR), decreased as increasing the Reynolds number. It has been found in the reaction experiment that the reaction rate is larger in laminar and singly-periodic wavy Taylor Vortex Flow regimes than in quasi-periodic and chaotic Taylor Vortex Flow regimes.
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Intercellular mass transfer in wavy/turbulent Taylor Vortex Flow
International Journal of Heat and Fluid Flow, 1998Co-Authors: Naoto Ohmura, Tsukasa Makino, Atsushi Motomura, Yuichiro Shibata, Kunio KataokaAbstract:Abstract Axial mass transfer or mixing through trains of cellular vortices has been observed in the range of time-dependent wavy Vortex Flow with the aid of visualization technique of wave motion, salt-tracer response technique, and spectral analysis of fluctuating velocity-gradients. There appear multiple stable Flow states even at the same Reynolds number owing to the hysteresis of the Flow system, depending upon the start-up operation. Intercellular mass transfer depends upon the axial wavelength and wave motion as well as the Reynolds number in the range of singly (SPWVF) and doubly periodic wavy Vortex Flow (DPWVF) whereas it is controlled mainly by turbulent motion in the range of weakly turbulent wavy Vortex (WTWVF) and fully turbulent Taylor Vortex Flows (TTVF). Intracellular mixing increases monotonically with Reynolds number, regardless of the Flow state.
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Emulsion polymerization of styrene in a continuous Taylor Vortex Flow reactor
Chemical Engineering Science, 1995Co-Authors: Kunio Kataoka, Naoto Ohmura, Masato Kouzu, Yosiharu Simamura, Masayoshi OkuboAbstract:Abstract A continuous emulsion polymerization of styrene was tried in a Taylor Vortex Flow reactor which has characteristics of a plug Flow reactor. The Taylor Vortex Flow reactor has the mixing characteristics appropriate for this reaction system. The steady-state conversion, the average molecular weight and the size distribution of latex particles can be controlled by the Flow condition as well as by the reaction temperature.
