The Experts below are selected from a list of 6 Experts worldwide ranked by ideXlab platform

Yi Wang - One of the best experts on this subject based on the ideXlab platform.

  • effect of air damping on quality factor of bulk mode microresonators
    Microelectronic Engineering, 2013
    Co-Authors: Bin Xiong, Yi Wang
    Abstract:

    In this paper, the air damping effect on quality factor of bulk mode microresonators is analyzed and measured. Both the squeeze film damping and slide film damping are considered in the analysis procedure. The reactions of the resonant plate with the air Flows in the transduction gaps and around the resonator plate surfaces are investigated based on the Reynolds equation and the Stoke-Flow model, respectively. An electrical equivalent model has been derived for a microresonator operating in air, based on the squeeze film damping and slide film damping effect. The model is realized with resistors equivalent for the slide film damping force and frequency-dependent resistors and capacitances connected in series equivalent for the squeeze film damping force. Circuit analysis tool is employed to calculate the response of the microresonator. The simulated transmission characteristics are in good agreement with the experimental results. Consequently, this approach provides a method to estimate the effect of air damping on the dynamic response of the micromechanical devices.

Bin Xiong - One of the best experts on this subject based on the ideXlab platform.

  • effect of air damping on quality factor of bulk mode microresonators
    Microelectronic Engineering, 2013
    Co-Authors: Bin Xiong, Yi Wang
    Abstract:

    In this paper, the air damping effect on quality factor of bulk mode microresonators is analyzed and measured. Both the squeeze film damping and slide film damping are considered in the analysis procedure. The reactions of the resonant plate with the air Flows in the transduction gaps and around the resonator plate surfaces are investigated based on the Reynolds equation and the Stoke-Flow model, respectively. An electrical equivalent model has been derived for a microresonator operating in air, based on the squeeze film damping and slide film damping effect. The model is realized with resistors equivalent for the slide film damping force and frequency-dependent resistors and capacitances connected in series equivalent for the squeeze film damping force. Circuit analysis tool is employed to calculate the response of the microresonator. The simulated transmission characteristics are in good agreement with the experimental results. Consequently, this approach provides a method to estimate the effect of air damping on the dynamic response of the micromechanical devices.

Johnsson Filip - One of the best experts on this subject based on the ideXlab platform.

  • Determination of the Apparent Viscosity of Dense Gas-Solids Emulsion by Magnetic Particle Tracking
    2018
    Co-Authors: K\uf6hler Anna, Pallar\ue8s David, Johnsson Filip
    Abstract:

    When designing fluidised bed units a key to ensure efficient conversion is proper control of the mixing of the fuel in both lateral and axial directions in the bed. In order to mechanistically describe the mixing of fuel particles in a fluidised bed, there is a need to determine the apparent viscosity of thegas-solids emulsion, which determines the drag on the fuel particles. In this work the apparent viscosity of a bed of spherical glass beads and air at minimum fluidisation was determined by means of the falling sphere method. Hereto the drag of the bed on a single immersed object was obtained by measuring the velocity of a negatively buoyant tracer with magneticparticle tracking (MPT). MPT allows for highly temporally and spatially resolved trajectories (10-3 s and 10-3 m, respectively) in all 3-dimensions. The bed consisted of glass beads with a narrow size distribution (215 to 250 μm) and tracers with a size from 5 to 20 mm and densities from 4340 to 7500kg/m3 were used. Hence, the literature, which typically covers data for velocities lying within or just above the Stoke Flow regime (0.002 < Re < 2.0) could be expanded to Re numbers (53 to 152) well within the transition Flow regime. The drag and apparent viscosity was compared to different fluidmodels and agreed well with the Newtonian model, when taking into account possible effects of the bed walls. Comparing the drag coefficient of data of free falling spheres and data of spheres falling with controlled velocities, the latter showed a dependence on the product of tracer diameter andfalling velocity, dput, while the former was constant over dput. This indicates the method with controlled falling velocities to be intrusive and influencing the result of the apparent viscosity of the bed. Using the free falling sphere method this work obtained an apparent viscosity of 0.24 Pa s, which isconsistent with values found in earlier literature for an emulsion of air and sand of similar size and density

K\uf6hler Anna - One of the best experts on this subject based on the ideXlab platform.

  • Determination of the Apparent Viscosity of Dense Gas-Solids Emulsion by Magnetic Particle Tracking
    2018
    Co-Authors: K\uf6hler Anna, Pallar\ue8s David, Johnsson Filip
    Abstract:

    When designing fluidised bed units a key to ensure efficient conversion is proper control of the mixing of the fuel in both lateral and axial directions in the bed. In order to mechanistically describe the mixing of fuel particles in a fluidised bed, there is a need to determine the apparent viscosity of thegas-solids emulsion, which determines the drag on the fuel particles. In this work the apparent viscosity of a bed of spherical glass beads and air at minimum fluidisation was determined by means of the falling sphere method. Hereto the drag of the bed on a single immersed object was obtained by measuring the velocity of a negatively buoyant tracer with magneticparticle tracking (MPT). MPT allows for highly temporally and spatially resolved trajectories (10-3 s and 10-3 m, respectively) in all 3-dimensions. The bed consisted of glass beads with a narrow size distribution (215 to 250 μm) and tracers with a size from 5 to 20 mm and densities from 4340 to 7500kg/m3 were used. Hence, the literature, which typically covers data for velocities lying within or just above the Stoke Flow regime (0.002 < Re < 2.0) could be expanded to Re numbers (53 to 152) well within the transition Flow regime. The drag and apparent viscosity was compared to different fluidmodels and agreed well with the Newtonian model, when taking into account possible effects of the bed walls. Comparing the drag coefficient of data of free falling spheres and data of spheres falling with controlled velocities, the latter showed a dependence on the product of tracer diameter andfalling velocity, dput, while the former was constant over dput. This indicates the method with controlled falling velocities to be intrusive and influencing the result of the apparent viscosity of the bed. Using the free falling sphere method this work obtained an apparent viscosity of 0.24 Pa s, which isconsistent with values found in earlier literature for an emulsion of air and sand of similar size and density

Pallar\ue8s David - One of the best experts on this subject based on the ideXlab platform.

  • Determination of the Apparent Viscosity of Dense Gas-Solids Emulsion by Magnetic Particle Tracking
    2018
    Co-Authors: K\uf6hler Anna, Pallar\ue8s David, Johnsson Filip
    Abstract:

    When designing fluidised bed units a key to ensure efficient conversion is proper control of the mixing of the fuel in both lateral and axial directions in the bed. In order to mechanistically describe the mixing of fuel particles in a fluidised bed, there is a need to determine the apparent viscosity of thegas-solids emulsion, which determines the drag on the fuel particles. In this work the apparent viscosity of a bed of spherical glass beads and air at minimum fluidisation was determined by means of the falling sphere method. Hereto the drag of the bed on a single immersed object was obtained by measuring the velocity of a negatively buoyant tracer with magneticparticle tracking (MPT). MPT allows for highly temporally and spatially resolved trajectories (10-3 s and 10-3 m, respectively) in all 3-dimensions. The bed consisted of glass beads with a narrow size distribution (215 to 250 μm) and tracers with a size from 5 to 20 mm and densities from 4340 to 7500kg/m3 were used. Hence, the literature, which typically covers data for velocities lying within or just above the Stoke Flow regime (0.002 < Re < 2.0) could be expanded to Re numbers (53 to 152) well within the transition Flow regime. The drag and apparent viscosity was compared to different fluidmodels and agreed well with the Newtonian model, when taking into account possible effects of the bed walls. Comparing the drag coefficient of data of free falling spheres and data of spheres falling with controlled velocities, the latter showed a dependence on the product of tracer diameter andfalling velocity, dput, while the former was constant over dput. This indicates the method with controlled falling velocities to be intrusive and influencing the result of the apparent viscosity of the bed. Using the free falling sphere method this work obtained an apparent viscosity of 0.24 Pa s, which isconsistent with values found in earlier literature for an emulsion of air and sand of similar size and density