The Experts below are selected from a list of 19510827 Experts worldwide ranked by ideXlab platform
Choon Hwai Yap - One of the best experts on this subject based on the ideXlab platform.
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a robust dual membrane dielectric elastomer actuator for large volume fluid pumping via snap through
Applied Physics Letters, 2017Co-Authors: Jia Zhu, Choon Chiang Foo, Choon Hwai YapAbstract:A pressurized dielectric elastomer (DE) diaphragm under electrical actuation can experience Snap-Through large deformation due to electromechanical instability, which was shown to be a promising mechanism for large volume fluid pumping. However, Snap-Through actuation in a DE fluid pump will not occur when the inlet pressure to the pump is small and cannot be robustly utilized for different applications. To solve this problem, in this study, we proposed a dual-membrane DE pump design featuring an active DE membrane interacting with a passive elastic membrane. This design enabled Snap-Through of the DE membrane over a wide range of inlet pressures, making it feasible for large volume fluid pumping even at low pressures. Merits of this dual-membrane DE actuator design were experimentally verified; for example, the pumping volume of the dual-membrane DE pump could be as large as 3944% of the pumping volume of the conventional single-membrane DE pump. We further proposed an analytical framework to describe th...
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the mechanism for large volume fluid pumping via reversible snap through of dielectric elastomer
Journal of Applied Physics, 2017Co-Authors: Yingxi Wang, Choon Chiang Foo, Hareesh Godaba, Jia Zhu, Choon Hwai YapAbstract:Giant deformation of dielectric elastomers (DEs) via electromechanical instability (or the “Snap-Through” phenomenon) is a promising mechanism for large-volume fluid pumping. Snap-Through of a DE membrane coupled with compressible air has been previously investigated. However, the physics behind reversible Snap-Through of a DE diaphragm coupled with incompressible fluid for the purpose of fluid pumping has not been well investigated, and the conditions required for reversible Snap-Through in a hydraulic system are unknown. In this study, we have proposed a concept for large-volume fluid pumping by harnessing reversible Snap-Through of the dielectric elastomer. The occurrence of Snap-Through was theoretically modeled and experimentally verified. Both the theoretical and experimental pressure-volume curves of the DE membrane under different actuation voltages were used to design the work loop of the pump, and the theoretical work loop agreed with the experimental work loop. Furthermore, the feasibility of r...
Reinhard Jahn - One of the best experts on this subject based on the ideXlab platform.
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α snap interferes with the zippering of the snare protein membrane fusion machinery
Journal of Biological Chemistry, 2014Co-Authors: Yongsoo Park, Wensi Vennekate, Peter Walla, Halenur Yavuz, Julia Preobraschenski, J M Hernandez, Dietmar Riedel, Reinhard JahnAbstract:Neuronal exocytosis is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Before fusion, SNARE proteins form complexes bridging the membrane followed by assembly toward the C-terminal membrane anchors, thus initiating membrane fusion. After fusion, the SNARE complex is disassembled by the AAA-ATPase N-ethylmaleimide-sensitive factor that requires the cofactor α-SNAP to first bind to the assembled SNARE complex. Using chromaffin granules and liposomes we now show that α-SNAP on its own interferes with the zippering of membrane-anchored SNARE complexes midway through the zippering reaction, arresting SNAREs in a partially assembled trans-complex and preventing fusion. Intriguingly, the interference does not result in an inhibitory effect on synaptic vesicles, suggesting that membrane properties also influence the final outcome of α-SNAP interference with SNARE zippering. We suggest that binding of α-SNAP to the SNARE complex affects the ability of the SNARE complex to harness energy or transmit force to the membrane.
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the n ethylmaleimide sensitive fusion protein and α snap induce a conformational change in syntaxin
Journal of Biological Chemistry, 1995Co-Authors: Phyllis I Hanson, Henning Otto, Nikki Barton, Reinhard JahnAbstract:The N-ethylmaleimide-sensitive fusion protein (NSF) plays an essential role in intracellular membrane fusion events and has been implicated in the exocytosis of synaptic vesicles. NSF binds through soluble NSF attachment proteins (SNAPs) to a complex of neuronal membrane proteins comprised of synaptobrevin, syntaxin, and SNAP-25. Disassembly of this complex by NSF is thought to be a critical step in the molecular events which lead to vesicle fusion with the plasma membrane. Here we have studied the interaction of α-SNAP and NSF with individual components of this complex and have identified syntaxin as a primary substrate for NSF/α-SNAP. We find that α-SNAP binds directly to syntaxin 1A as well as weakly to SNAP-25, while it does not bind to synaptobrevin II. NSF binds to syntaxin through α-SNAP and in the presence of ATP catalyzes a conformational rearrangement which abolishes binding of itself and α-SNAP. This reaction leads to the previously described disassembly of the fusion complex, since synaptobrevin binding to syntaxin is also reduced. α-SNAP binds to a carboxyl-terminal syntaxin fragment (residues 194-288) that also binds synaptobrevin and SNAP-25. However, NSF action on this syntaxin fragment has no effect on the binding of α-SNAP or synaptobrevin. This suggests that the conformational change normally induced by NSF in syntaxin depends on an interaction between carboxyl- and amino-terminal domains of syntaxin.
Jia Zhu - One of the best experts on this subject based on the ideXlab platform.
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a robust dual membrane dielectric elastomer actuator for large volume fluid pumping via snap through
Applied Physics Letters, 2017Co-Authors: Jia Zhu, Choon Chiang Foo, Choon Hwai YapAbstract:A pressurized dielectric elastomer (DE) diaphragm under electrical actuation can experience Snap-Through large deformation due to electromechanical instability, which was shown to be a promising mechanism for large volume fluid pumping. However, Snap-Through actuation in a DE fluid pump will not occur when the inlet pressure to the pump is small and cannot be robustly utilized for different applications. To solve this problem, in this study, we proposed a dual-membrane DE pump design featuring an active DE membrane interacting with a passive elastic membrane. This design enabled Snap-Through of the DE membrane over a wide range of inlet pressures, making it feasible for large volume fluid pumping even at low pressures. Merits of this dual-membrane DE actuator design were experimentally verified; for example, the pumping volume of the dual-membrane DE pump could be as large as 3944% of the pumping volume of the conventional single-membrane DE pump. We further proposed an analytical framework to describe th...
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the mechanism for large volume fluid pumping via reversible snap through of dielectric elastomer
Journal of Applied Physics, 2017Co-Authors: Yingxi Wang, Choon Chiang Foo, Hareesh Godaba, Jia Zhu, Choon Hwai YapAbstract:Giant deformation of dielectric elastomers (DEs) via electromechanical instability (or the “Snap-Through” phenomenon) is a promising mechanism for large-volume fluid pumping. Snap-Through of a DE membrane coupled with compressible air has been previously investigated. However, the physics behind reversible Snap-Through of a DE diaphragm coupled with incompressible fluid for the purpose of fluid pumping has not been well investigated, and the conditions required for reversible Snap-Through in a hydraulic system are unknown. In this study, we have proposed a concept for large-volume fluid pumping by harnessing reversible Snap-Through of the dielectric elastomer. The occurrence of Snap-Through was theoretically modeled and experimentally verified. Both the theoretical and experimental pressure-volume curves of the DE membrane under different actuation voltages were used to design the work loop of the pump, and the theoretical work loop agreed with the experimental work loop. Furthermore, the feasibility of r...
Choon Chiang Foo - One of the best experts on this subject based on the ideXlab platform.
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a robust dual membrane dielectric elastomer actuator for large volume fluid pumping via snap through
Applied Physics Letters, 2017Co-Authors: Jia Zhu, Choon Chiang Foo, Choon Hwai YapAbstract:A pressurized dielectric elastomer (DE) diaphragm under electrical actuation can experience Snap-Through large deformation due to electromechanical instability, which was shown to be a promising mechanism for large volume fluid pumping. However, Snap-Through actuation in a DE fluid pump will not occur when the inlet pressure to the pump is small and cannot be robustly utilized for different applications. To solve this problem, in this study, we proposed a dual-membrane DE pump design featuring an active DE membrane interacting with a passive elastic membrane. This design enabled Snap-Through of the DE membrane over a wide range of inlet pressures, making it feasible for large volume fluid pumping even at low pressures. Merits of this dual-membrane DE actuator design were experimentally verified; for example, the pumping volume of the dual-membrane DE pump could be as large as 3944% of the pumping volume of the conventional single-membrane DE pump. We further proposed an analytical framework to describe th...
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the mechanism for large volume fluid pumping via reversible snap through of dielectric elastomer
Journal of Applied Physics, 2017Co-Authors: Yingxi Wang, Choon Chiang Foo, Hareesh Godaba, Jia Zhu, Choon Hwai YapAbstract:Giant deformation of dielectric elastomers (DEs) via electromechanical instability (or the “Snap-Through” phenomenon) is a promising mechanism for large-volume fluid pumping. Snap-Through of a DE membrane coupled with compressible air has been previously investigated. However, the physics behind reversible Snap-Through of a DE diaphragm coupled with incompressible fluid for the purpose of fluid pumping has not been well investigated, and the conditions required for reversible Snap-Through in a hydraulic system are unknown. In this study, we have proposed a concept for large-volume fluid pumping by harnessing reversible Snap-Through of the dielectric elastomer. The occurrence of Snap-Through was theoretically modeled and experimentally verified. Both the theoretical and experimental pressure-volume curves of the DE membrane under different actuation voltages were used to design the work loop of the pump, and the theoretical work loop agreed with the experimental work loop. Furthermore, the feasibility of r...
Christopher R. Bowen - One of the best experts on this subject based on the ideXlab platform.
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Modelling of piezoelectrically actuated bistable composites
Materials Letters, 2011Co-Authors: Peter Giddings, Aki I.t. Salo, Christopher R. BowenAbstract:Abstract Bistable asymmetric composites with piezoelectric actuators that induce ‘Snap-Through’ from one stable state to another are candidate smart materials for shape-change (morphing) applications. This paper combines a homogenised piezoelectric model of a Macro Fibre Composite with a bistable asymmetric laminate model. Both predicted shape and Snap-Through voltage of a piezo-actuated [0/90] T laminate compare favourably with experimental results.
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Characterisation of Force-Deflection Behaviour of Piezoelectrically Actuated Bistable Composite Laminate under Two-Axis Constraint
Advances in Science and Technology, 2008Co-Authors: Peter Giddings, Christopher R. BowenAbstract:This paper characterises the properties of unsymmetric bistable carbon fibre composites actuated using a single piezoelectric macro fibre actuator. A piezoelectric–laminate combination under two-axis constraint was evaluated in terms of its load–deflection characteristics, Snap-Through force and stiffness. The load–deflection characteristics indicate that Snap-Through force and laminate stiffness increase as a function of piezoelectric actuator drive-voltage. Both Snap-Through force and laminate stiffness are significantly increased under two-axis constraint, as compared to single-axis constraint. Snap-Through force and stiffness are shown to be affected by localised curvature variation caused by laminate ageing.
