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Tai-shung Chung - One of the best experts on this subject based on the ideXlab platform.

  • particle size effects on gas transport properties of 6fda durene zif 71 mixed matrix membranes
    Industrial & Engineering Chemistry Research, 2016
    Co-Authors: Susilo Japip, Youchang Xiao, Tai-shung Chung
    Abstract:

    A series of 6FDA-Durene-ZIF71 mixed matrix membranes (MMMs) comprising three different ZIF-71 particle sizes (i.e., 30, 200, and 600 nm) have been fabricated to investigate the effects of particle size on the gas separation performance of MMMs. Compared to MMMs containing ZIF-71 particle size > 200 nm, ZIF-71 embedded MMMs with particle sizes of ≤ 200 nm exhibited significantly enhanced gas separation performance. The O2 and N2 permeability of MMMs comprising ZIF-71 with particle sizes ≤ 200 nm have higher permeability than the predicted ones using the Maxwell Model. By considering the inefficiently packed polymer chain and the sieve-in-a-cage phenomena, the modified Maxwell Model displayed comparable permeability over the experimental results suggesting the nonideal nature of MMMs. For the first time, it was found that 200 nm ZIF-71 generated the best MMM for gas separation, particularly for H2/CH4 systems. Therefore, a trade-off between ZIF-71 particle size vs gas separation performance must be taken in...

  • Particle-Size Effects on Gas Transport Properties of 6FDA-Durene/ZIF-71 Mixed Matrix Membranes
    2016
    Co-Authors: Susilo Japip, Youchang Xiao, Tai-shung Chung
    Abstract:

    A series of 6FDA-Durene-ZIF71 mixed matrix membranes (MMMs) comprising three different ZIF-71 particle sizes (i.e., 30, 200, and 600 nm) have been fabricated to investigate the effects of particle size on the gas separation performance of MMMs. Compared to MMMs containing ZIF-71 particle size > 200 nm, ZIF-71 embedded MMMs with particle sizes of ≤ 200 nm exhibited significantly enhanced gas separation performance. The O2 and N2 permeability of MMMs comprising ZIF-71 with particle sizes ≤ 200 nm have higher permeability than the predicted ones using the Maxwell Model. By considering the inefficiently packed polymer chain and the sieve-in-a-cage phenomena, the modified Maxwell Model displayed comparable permeability over the experimental results suggesting the nonideal nature of MMMs. For the first time, it was found that 200 nm ZIF-71 generated the best MMM for gas separation, particularly for H2/CH4 systems. Therefore, a trade-off between ZIF-71 particle size vs gas separation performance must be taken into account when designing an MMM suitable for industrial gas separation applications

  • Effects of novel silane modification of zeolite surface on polymer chain rigidification and partial pore blockage in polyethersulfone (PES)-zeolite A mixed matrix membranes
    Journal of Membrane Science, 2006
    Co-Authors: Yi Li, Tai-shung Chung, Huai-min Guan, Santi Kulprathipanja
    Abstract:

    A novel silane coupling agent, (3-aminopropyl)-diethoxymethyl silane (APDEMS) was used in this work to modify zeolite surface for mixed matrix membranes (MMMs). Both elementary analysis and XPS spectra confirm the chemical modification, while BET measurements show no changes in zeolite surface area and total pore volume after the modification. Polyethersulfone (PES)-zeolite 3A, 4A and 5A MMMs were fabricated at high processing temperatures using unmodified and chemical modified zeolite. SEM images of these MMMs indicate the interface between polymer and zeolite phases becomes better if modified zeolite is used. The effects of chemical modification of zeolite surface and zeolite loadings on the gas separation performance of these MMMs were investigated. Both permeability and selectivity of MMMs made from APDEMS modified zeolite are higher than those of MMMs made from unmodified zeolite at 20 wt% zeolite loading because of a decrease in the degree of partial pore blockage of zeolites. The permeability of all studied gases decreases with increasing zeolite content for PES-zeolite 4A-NH2 MMMs, while for PES-zeolite 5A-NH2 MMMs, the gas permeability decreases and then increases with an increase in zeolite loadings. This unique phenomenon implies that using large pore-size zeolite for MMMs would potentially offset the negative effects of partial pore blockage and polymer chain rigidification on permeability. A modified Maxwell Model with adjusted parameters was applied to study the PES-zeolite 4A-NH 2 MMM system. The predicted permeability and selectivity show very good agreement with experimental data, indicating the modified Maxwell Model is fully capable of predicting the gas separation performance of MMMs made from both unmodified and modified zeolite. © 2005 Elsevier B.V. All rights reserved.

Masatoshi Ishikawa - One of the best experts on this subject based on the ideXlab platform.

  • adaptive visual shock absorber with visual based Maxwell Model using a magnetic gear
    International Conference on Robotics and Automation, 2020
    Co-Authors: Satoshi Tanaka, Keisuke Koyama, Taku Senoo, Masatoshi Ishikawa
    Abstract:

    In this study, a visual shock absorber capable of adapting to free-fall objects with various weights and speeds is designed and realized. The key element is a magnetic gear to passively absorb shock in the moment of contact, which is difficult for traditional feedback control to deal with. The magnetic gear allows the seamless transfer of control from the non-contact state to the contact state. 1000 Hz high-speed visual object tracking is used for preparation with position and velocity control in the object non-contact state. In the moment of object contact, the high backdrivability of the magnetic gear response by hardware provides high responsiveness to external force. After the impact, the plastic deformation control of a parallel-expressed Maxwell Model handles the contact state.

  • impedance control design based on plastic deformation for a robotic arm
    International Conference on Robotics and Automation, 2017
    Co-Authors: Taku Senoo, Masanori Koike, Kenichi Murakami, Masatoshi Ishikawa
    Abstract:

    In this study, the impedance control for smoothly receiving the impact of an incoming object is designed and realized. The control strategy is based on the idea that the back drive motion of an end effector attributable to the collision impact is regarded as plastic deformation of the robot. The impedance dynamics are constructed from the Maxwell Model, which describes plastic deformation. Next, two types of control methods are proposed in terms of the connection configuration of the spring and damper. Physical simulations of the impact absorption with a robotic arm are executed to validate and analyze the proposed control laws.

  • visual shock absorber based on Maxwell Model for anti rebound control
    Intelligent Robots and Systems, 2015
    Co-Authors: Taku Senoo, Masanori Koike, Kenichi Murakami, Masatoshi Ishikawa
    Abstract:

    A visually guided shock absorber for high-speed catching without rebound is designed and realized. This visual shock absorber is based on the Maxwell Model, which uses plastic deformation to suppress rebounding. The shock absorber is constructed from a spring-based passive elastic body and a servo control-based software damper connected in series. The visual shock absorber is realized in a robot with two degrees of freedom and high-speed vision. The robot receives the impact of a rolling object without repelling it.

Chaimongkol Saengow - One of the best experts on this subject based on the ideXlab platform.

  • exact analytical solution for large amplitude oscillatory shear flow from oldroyd 8 constant framework shear stress
    Physics of Fluids, 2017
    Co-Authors: Chaimongkol Saengow, A J Giacomin, Chanyut Kolitawong
    Abstract:

    The Oldroyd 8-constant Model is a continuum framework containing, as special cases, many important constitutive equations for elastic liquids. When polymeric liquids undergo large-amplitude oscillatory shear flow, the shear stress responds as a Fourier series, the higher harmonics of which are caused by the fluid nonlinearity. We choose this continuum framework for its rich diversity of special cases (we tabulate 14 of these). Deepening our understanding of this Oldroyd 8-constant framework thus at once deepens our understanding of every one of these special cases. Previously [C. Saengow et al., Macromol. Theory Simul. 24, 352 (2015)], we arrived at an exact analytical solution for the corotational Maxwell Model. Here, we derive the exact analytical expression for the Oldroyd 8-constant framework for the shear stress response in large-amplitude oscillatory shear flow. Our exact solution reduces to our previous solution for the special case of the corotational Maxwell Model, as it should. Our worked exampl...

  • exact analytical solution for large amplitude oscillatory shear flow
    Macromolecular Theory and Simulations, 2015
    Co-Authors: Chaimongkol Saengow, A J Giacomin, Chanyut Kolitawong
    Abstract:

    When polymeric liquids undergo large-amplitude shearing oscillations, the shear stress responds as a Fourier series, the higher harmonics of which are caused by fluid nonlinearity. Previous work on large-amplitude oscillatory shear flow has produced analytical solutions for the first few harmonics of a Fourier series for the shear stress response (none beyond the fifth) or for the normal stress difference responses (none beyond the fourth) [JNNFM, 166, 1081 (2011)], but this growing subdiscipline of macromolecular physics has yet to produce an exact solution. Here, we derive what we believe to be the first exact analytical solution for the response of the extra stress tensor in large-amplitude oscillatory shear flow. Our solution, unique and in closed form, includes both the normal stress differences and the shear stress for both startup and alternance. We solve the corotational Maxwell Model as a pair of nonlinear-coupled ordinary differential equations, simultaneously. We choose the corotational Maxwell Model because this two-parameter Model (η0 and λ) is the simplest constitutive Model relevant to large-amplitude oscillatory shear flow, and because it has previously been found to be accurate for molten plastics (when multiple relaxation times are used). By relevant we mean that the Model predicts higher harmonics. We find good agreement between the first few harmonics of our exact solution, and of our previous approximate expressions (obtained using the Goddard integral transform). Our exact solution agrees closely with the measured behavior for molten plastics, not only at alternance, but also in startup.

Susilo Japip - One of the best experts on this subject based on the ideXlab platform.

  • particle size effects on gas transport properties of 6fda durene zif 71 mixed matrix membranes
    Industrial & Engineering Chemistry Research, 2016
    Co-Authors: Susilo Japip, Youchang Xiao, Tai-shung Chung
    Abstract:

    A series of 6FDA-Durene-ZIF71 mixed matrix membranes (MMMs) comprising three different ZIF-71 particle sizes (i.e., 30, 200, and 600 nm) have been fabricated to investigate the effects of particle size on the gas separation performance of MMMs. Compared to MMMs containing ZIF-71 particle size > 200 nm, ZIF-71 embedded MMMs with particle sizes of ≤ 200 nm exhibited significantly enhanced gas separation performance. The O2 and N2 permeability of MMMs comprising ZIF-71 with particle sizes ≤ 200 nm have higher permeability than the predicted ones using the Maxwell Model. By considering the inefficiently packed polymer chain and the sieve-in-a-cage phenomena, the modified Maxwell Model displayed comparable permeability over the experimental results suggesting the nonideal nature of MMMs. For the first time, it was found that 200 nm ZIF-71 generated the best MMM for gas separation, particularly for H2/CH4 systems. Therefore, a trade-off between ZIF-71 particle size vs gas separation performance must be taken in...

  • Particle-Size Effects on Gas Transport Properties of 6FDA-Durene/ZIF-71 Mixed Matrix Membranes
    2016
    Co-Authors: Susilo Japip, Youchang Xiao, Tai-shung Chung
    Abstract:

    A series of 6FDA-Durene-ZIF71 mixed matrix membranes (MMMs) comprising three different ZIF-71 particle sizes (i.e., 30, 200, and 600 nm) have been fabricated to investigate the effects of particle size on the gas separation performance of MMMs. Compared to MMMs containing ZIF-71 particle size > 200 nm, ZIF-71 embedded MMMs with particle sizes of ≤ 200 nm exhibited significantly enhanced gas separation performance. The O2 and N2 permeability of MMMs comprising ZIF-71 with particle sizes ≤ 200 nm have higher permeability than the predicted ones using the Maxwell Model. By considering the inefficiently packed polymer chain and the sieve-in-a-cage phenomena, the modified Maxwell Model displayed comparable permeability over the experimental results suggesting the nonideal nature of MMMs. For the first time, it was found that 200 nm ZIF-71 generated the best MMM for gas separation, particularly for H2/CH4 systems. Therefore, a trade-off between ZIF-71 particle size vs gas separation performance must be taken into account when designing an MMM suitable for industrial gas separation applications

Taku Senoo - One of the best experts on this subject based on the ideXlab platform.

  • adaptive visual shock absorber with visual based Maxwell Model using a magnetic gear
    International Conference on Robotics and Automation, 2020
    Co-Authors: Satoshi Tanaka, Keisuke Koyama, Taku Senoo, Masatoshi Ishikawa
    Abstract:

    In this study, a visual shock absorber capable of adapting to free-fall objects with various weights and speeds is designed and realized. The key element is a magnetic gear to passively absorb shock in the moment of contact, which is difficult for traditional feedback control to deal with. The magnetic gear allows the seamless transfer of control from the non-contact state to the contact state. 1000 Hz high-speed visual object tracking is used for preparation with position and velocity control in the object non-contact state. In the moment of object contact, the high backdrivability of the magnetic gear response by hardware provides high responsiveness to external force. After the impact, the plastic deformation control of a parallel-expressed Maxwell Model handles the contact state.

  • impedance control design based on plastic deformation for a robotic arm
    International Conference on Robotics and Automation, 2017
    Co-Authors: Taku Senoo, Masanori Koike, Kenichi Murakami, Masatoshi Ishikawa
    Abstract:

    In this study, the impedance control for smoothly receiving the impact of an incoming object is designed and realized. The control strategy is based on the idea that the back drive motion of an end effector attributable to the collision impact is regarded as plastic deformation of the robot. The impedance dynamics are constructed from the Maxwell Model, which describes plastic deformation. Next, two types of control methods are proposed in terms of the connection configuration of the spring and damper. Physical simulations of the impact absorption with a robotic arm are executed to validate and analyze the proposed control laws.

  • visual shock absorber based on Maxwell Model for anti rebound control
    Intelligent Robots and Systems, 2015
    Co-Authors: Taku Senoo, Masanori Koike, Kenichi Murakami, Masatoshi Ishikawa
    Abstract:

    A visually guided shock absorber for high-speed catching without rebound is designed and realized. This visual shock absorber is based on the Maxwell Model, which uses plastic deformation to suppress rebounding. The shock absorber is constructed from a spring-based passive elastic body and a servo control-based software damper connected in series. The visual shock absorber is realized in a robot with two degrees of freedom and high-speed vision. The robot receives the impact of a rolling object without repelling it.