The Experts below are selected from a list of 17973 Experts worldwide ranked by ideXlab platform
Mehmet Tomak - One of the best experts on this subject based on the ideXlab platform.
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Electron polarization in a parabolic quantum well with Uniform Electric Field
Superlattices and Microstructures, 1991Co-Authors: K. F. Ilaiwi, Mehmet TomakAbstract:Abstract The polarization of a quantum electron confined in a parabolic quantum well in the presence of a Uniform Electric Field is calculated numerically. We find positive polarization for both ground and the first excited states.
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Electron polarization in a quantum well with Uniform Electric Field
Solid State Communications, 1991Co-Authors: K. F. Ilaiwi, Mehmet TomakAbstract:Abstract The polarization of a quantum electron confined in a one-dimensional potential well in the presence of a Uniform Electric Field is calculated numerically. We find that the negative polarization of the first excited state in previous calculations is solely due to the neglect of the Electric Field outside the quantum well.
Suman Chakraborty - One of the best experts on this subject based on the ideXlab platform.
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electrohydrodynamics of confined two dimensional liquid droplets in Uniform Electric Field
Physics of Fluids, 2018Co-Authors: Somnath Santra, Shubhadeep Mandal, Suman ChakrabortyAbstract:In this study, the electrohydrodynamics of viscous droplets in a confined domain under the action of a Uniform Electric Field is investigated numerically. Considering both the phases to be perfect diElectric or leaky diElectric, two-dimensional numerical simulations are performed to obtain the shape deformation of droplets placed between two parallel plate electrodes. The aim of this study is to show the effect of domain confinement on the droplet morphology and temporal droplet deformation. Perfect diElectric systems always deform into a prolate shape, and the magnitude of deformation is augmented or reduced in a confined domain depending on the Electrical permittivity ratio. For leaky diElectric systems, the Electrical conductivity ratio comes into play and the droplet can attain an oblate or prolate shape depending on the size of the droplet relative to the channel height. A regime diagram is constructed to show the impact of domain confinement on the droplet shape. Additionally, the steady-state deformation parameter undergoes some non-monotonic variation with domain confinement for the leaky diElectric systems. The domain confinement can significantly decrease the droplet deformation and thereby suppress the droplet breakup phenomenon for few leaky diElectric systems. The domain confinement markedly affects the temporal evolution of the droplet deformation. The temporal evolution of the droplet shape shows that the droplet deforms more sluggishly toward its final steady configuration in a confined domain when the inertial effects are negligible. The oscillations in droplet deformation at the finite inertial regime are also suppressed in a confined domain. Finally, the interaction of two droplets is also studied, which shows that coalescence and detachment of the droplet pairs take place at a slower rate in a confined domain with respect to an unbounded domain. Thus, the present study shows the possibility of modulating the droplet morphology by tuning the domain confinement, which can be of potential use in designing droplet-based microfluidic devices.In this study, the electrohydrodynamics of viscous droplets in a confined domain under the action of a Uniform Electric Field is investigated numerically. Considering both the phases to be perfect diElectric or leaky diElectric, two-dimensional numerical simulations are performed to obtain the shape deformation of droplets placed between two parallel plate electrodes. The aim of this study is to show the effect of domain confinement on the droplet morphology and temporal droplet deformation. Perfect diElectric systems always deform into a prolate shape, and the magnitude of deformation is augmented or reduced in a confined domain depending on the Electrical permittivity ratio. For leaky diElectric systems, the Electrical conductivity ratio comes into play and the droplet can attain an oblate or prolate shape depending on the size of the droplet relative to the channel height. A regime diagram is constructed...
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Effect of Uniform Electric Field on the drop deformation in simple shear flow and emulsion shear rheology
Physics of Fluids, 2017Co-Authors: Shubhadeep Mandal, Suman ChakrabortyAbstract:Electrohydrodynamic deformation and orientation of a neutrally buoyant, leaky diElectric, Newtonian drop suspended in another immiscible, leaky diElectric, Newtonian medium is analyzed under the combined influence of Uniform Electric Field and simple shear flow. Application of Uniform Electric Field, perpendicular to the direction of shear flow, not only deforms the drop but also modifies the rheological behavior of a dilute emulsion. In the creeping flow limit, an analytical solution for the deformed drop shape is obtained when the drop shape remains nearly spherical and the surface charge convection is weak. The effective shear rheology is obtained for a dilute emulsion of non-interacting drops by calculating the one-particle contribution to the emulsion stress. The results show that the combined influence of Uniform Electric Field and shear flow is not a simple linear superposition of the independent contributions from Electric Field and shear flow. Application of Uniform Electric Field always leads to...
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Uniform Electric Field induced lateral migration of a sedimenting drop
arXiv: Fluid Dynamics, 2015Co-Authors: Aditya Bandopadhyay, Shubhadeep Mandal, Suman ChakrabortyAbstract:We investigate the motion of a sedimenting spherical drop in the presence of an applied Uniform Electric Field in an otherwise arbitrary direction in the limit of low surface charge convection. We analytically solve the Electric potential in and around the leaky diElectric drop, and solve for the Stokesian velocity and pressure Fields. We obtain the drop velocity through perturbations in powers of the Electric Reynolds number which signifies the importance of the charge relaxation time scale as compared to the convective time scale. We show that in the presence of Electric Field either in the sedimenting direction or orthogonal to it, there is a change in the drop velocity only in the direction of sedimentation due to an asymmetric charge distribution in the same direction. However, in the presence of an Electric Field applied in both the directions, and depending on the permittivities and conductivities of the two fluids, we obtain a non-intuitive lateral migration of drop in addition to the buoyancy driven sedimentation. These dynamical features can be effectively used for manipulating drops in a controlled electro-fluidic environment.
K. F. Ilaiwi - One of the best experts on this subject based on the ideXlab platform.
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Electron polarization in a parabolic quantum well with Uniform Electric Field
Superlattices and Microstructures, 1991Co-Authors: K. F. Ilaiwi, Mehmet TomakAbstract:Abstract The polarization of a quantum electron confined in a parabolic quantum well in the presence of a Uniform Electric Field is calculated numerically. We find positive polarization for both ground and the first excited states.
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Electron polarization in a quantum well with Uniform Electric Field
Solid State Communications, 1991Co-Authors: K. F. Ilaiwi, Mehmet TomakAbstract:Abstract The polarization of a quantum electron confined in a one-dimensional potential well in the presence of a Uniform Electric Field is calculated numerically. We find that the negative polarization of the first excited state in previous calculations is solely due to the neglect of the Electric Field outside the quantum well.
Shubhadeep Mandal - One of the best experts on this subject based on the ideXlab platform.
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electrohydrodynamics of confined two dimensional liquid droplets in Uniform Electric Field
Physics of Fluids, 2018Co-Authors: Somnath Santra, Shubhadeep Mandal, Suman ChakrabortyAbstract:In this study, the electrohydrodynamics of viscous droplets in a confined domain under the action of a Uniform Electric Field is investigated numerically. Considering both the phases to be perfect diElectric or leaky diElectric, two-dimensional numerical simulations are performed to obtain the shape deformation of droplets placed between two parallel plate electrodes. The aim of this study is to show the effect of domain confinement on the droplet morphology and temporal droplet deformation. Perfect diElectric systems always deform into a prolate shape, and the magnitude of deformation is augmented or reduced in a confined domain depending on the Electrical permittivity ratio. For leaky diElectric systems, the Electrical conductivity ratio comes into play and the droplet can attain an oblate or prolate shape depending on the size of the droplet relative to the channel height. A regime diagram is constructed to show the impact of domain confinement on the droplet shape. Additionally, the steady-state deformation parameter undergoes some non-monotonic variation with domain confinement for the leaky diElectric systems. The domain confinement can significantly decrease the droplet deformation and thereby suppress the droplet breakup phenomenon for few leaky diElectric systems. The domain confinement markedly affects the temporal evolution of the droplet deformation. The temporal evolution of the droplet shape shows that the droplet deforms more sluggishly toward its final steady configuration in a confined domain when the inertial effects are negligible. The oscillations in droplet deformation at the finite inertial regime are also suppressed in a confined domain. Finally, the interaction of two droplets is also studied, which shows that coalescence and detachment of the droplet pairs take place at a slower rate in a confined domain with respect to an unbounded domain. Thus, the present study shows the possibility of modulating the droplet morphology by tuning the domain confinement, which can be of potential use in designing droplet-based microfluidic devices.In this study, the electrohydrodynamics of viscous droplets in a confined domain under the action of a Uniform Electric Field is investigated numerically. Considering both the phases to be perfect diElectric or leaky diElectric, two-dimensional numerical simulations are performed to obtain the shape deformation of droplets placed between two parallel plate electrodes. The aim of this study is to show the effect of domain confinement on the droplet morphology and temporal droplet deformation. Perfect diElectric systems always deform into a prolate shape, and the magnitude of deformation is augmented or reduced in a confined domain depending on the Electrical permittivity ratio. For leaky diElectric systems, the Electrical conductivity ratio comes into play and the droplet can attain an oblate or prolate shape depending on the size of the droplet relative to the channel height. A regime diagram is constructed...
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Effect of Uniform Electric Field on the drop deformation in simple shear flow and emulsion shear rheology
Physics of Fluids, 2017Co-Authors: Shubhadeep Mandal, Suman ChakrabortyAbstract:Electrohydrodynamic deformation and orientation of a neutrally buoyant, leaky diElectric, Newtonian drop suspended in another immiscible, leaky diElectric, Newtonian medium is analyzed under the combined influence of Uniform Electric Field and simple shear flow. Application of Uniform Electric Field, perpendicular to the direction of shear flow, not only deforms the drop but also modifies the rheological behavior of a dilute emulsion. In the creeping flow limit, an analytical solution for the deformed drop shape is obtained when the drop shape remains nearly spherical and the surface charge convection is weak. The effective shear rheology is obtained for a dilute emulsion of non-interacting drops by calculating the one-particle contribution to the emulsion stress. The results show that the combined influence of Uniform Electric Field and shear flow is not a simple linear superposition of the independent contributions from Electric Field and shear flow. Application of Uniform Electric Field always leads to...
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Uniform Electric Field induced lateral migration of a sedimenting drop
arXiv: Fluid Dynamics, 2015Co-Authors: Aditya Bandopadhyay, Shubhadeep Mandal, Suman ChakrabortyAbstract:We investigate the motion of a sedimenting spherical drop in the presence of an applied Uniform Electric Field in an otherwise arbitrary direction in the limit of low surface charge convection. We analytically solve the Electric potential in and around the leaky diElectric drop, and solve for the Stokesian velocity and pressure Fields. We obtain the drop velocity through perturbations in powers of the Electric Reynolds number which signifies the importance of the charge relaxation time scale as compared to the convective time scale. We show that in the presence of Electric Field either in the sedimenting direction or orthogonal to it, there is a change in the drop velocity only in the direction of sedimentation due to an asymmetric charge distribution in the same direction. However, in the presence of an Electric Field applied in both the directions, and depending on the permittivities and conductivities of the two fluids, we obtain a non-intuitive lateral migration of drop in addition to the buoyancy driven sedimentation. These dynamical features can be effectively used for manipulating drops in a controlled electro-fluidic environment.
Yia-chung Chang - One of the best experts on this subject based on the ideXlab platform.
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Effects of J-gate potential and Uniform Electric Field on a coupled donor pair in Si for quantum computing
Physical Review B, 2002Co-Authors: Angbo Fang, Yia-chung Chang, J. R. TuckerAbstract:We present theoretical studies of a coupled-donor pair in Si via an unrestricted Hartree-Fock method with a generalized valence bond wave function. Polarization properties and exchange coupling for a phosphorous donor pair in silicon under a J-gate potential (modeled by a parabolic well) and a Uniform Electric Field (either parallel or perpendicular to the interdonor axis) are examined. The energies and charge distributions of the lowest-lying singlet and triplet states as functions of the J-gate potential and Uniform Electric Field for various donor separations are analyzed. Implications for Si:P electron-spin-based quantum computer architecture are discussed.
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electron tunneling rate in quantum dots under a Uniform Electric Field
Physical Review B, 2000Co-Authors: David M T Kuo, Yia-chung ChangAbstract:A stabilization method is used to evaluate the tunneling rate of an electron in isolated quantum dots of conical shape under Uniform Electric Field. A stabilization graph is obtained by plotting the eigenvalues of a single quantum dot embedded in a confining box made of barrier material as functions of the size of the box. The eigenvalues of the system are calculated within the effective mass approximation via the Raleigh-Ritz variational method. The density of states associated with the quasibound state is constructed from the stabilization graph and is shown to have a Lorentzian profile. The width of the Lorentzian profile gives the tunneling rate. We show that the tunneling rate of the quantum dot system is 2--3 times smaller than that of a quantum well system with the same bound-to-continuum transition energy.
