The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
J J Alvaradogil - One of the best experts on this subject based on the ideXlab platform.
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a constitutive equation for nano to macro scale heat conduction based on the boltzmann transport equation
Journal of Applied Physics, 2011Co-Authors: Jose Ordonezmiranda, Ronggui Yang, J J AlvaradogilAbstract:A constitutive equation for heat conduction is derived from the exact solution of the Boltzmann transport equation under the relaxation time approximation. This is achieved by a series expansion on multiple space derivatives of the temperature and introducing the concept of thermal Multipoles, where the thermal conductivity defined under the framework of the Fourier law of heat conduction is just the first thermal pole. It is shown that this equation generalizes the Fourier law and Cattaneo equation of heat conduction, and it depends strongly on the relative values of the length and time scales compared with the mean-free path and mean-free time of the energy carriers, respectively. In the limiting case of steady-state heat conduction, it is shown that the heat flux vector depends on a spatial scale ratio whose effects are remarkable in the micro-scale spatial domains. By applying a first-order approximation of the obtained thermal Multipole expansion to the problem of transient heat conduction across a t...
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a constitutive equation for nano to macro scale heat conduction based on the boltzmann transport equation
Journal of Applied Physics, 2011Co-Authors: Jose Ordonezmiranda, Ronggui Yang, J J AlvaradogilAbstract:A constitutive equation for heat conduction is derived from the exact solution of the Boltzmann transport equation under the relaxation time approximation. This is achieved by a series expansion on multiple space derivatives of the temperature and introducing the concept of thermal Multipoles, where the thermal conductivity defined under the framework of the Fourier law of heat conduction is just the first thermal pole. It is shown that this equation generalizes the Fourier law and Cattaneo equation of heat conduction, and it depends strongly on the relative values of the length and time scales compared with the mean-free path and mean-free time of the energy carriers, respectively. In the limiting case of steady-state heat conduction, it is shown that the heat flux vector depends on a spatial scale ratio whose effects are remarkable in the micro-scale spatial domains. By applying a first-order approximation of the obtained thermal Multipole expansion to the problem of transient heat conduction across a thin film and comparing the results with the predictions for the same problem using the Fourier, Cattaneo and Boltzmann transport equations, it is shown that our results could be useful in the study of the heat transport in short as well as in long scales of space and time. The common and different features of the Multipole expansion compared with the Ballistic-diffusive model of heat conduction are also discussed. Special emphasis is put to the cases where the physical scales of space and time are comparable to the mean-free path and mean-free time of the energy carriers.
Jose Ordonezmiranda - One of the best experts on this subject based on the ideXlab platform.
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a constitutive equation for nano to macro scale heat conduction based on the boltzmann transport equation
Journal of Applied Physics, 2011Co-Authors: Jose Ordonezmiranda, Ronggui Yang, J J AlvaradogilAbstract:A constitutive equation for heat conduction is derived from the exact solution of the Boltzmann transport equation under the relaxation time approximation. This is achieved by a series expansion on multiple space derivatives of the temperature and introducing the concept of thermal Multipoles, where the thermal conductivity defined under the framework of the Fourier law of heat conduction is just the first thermal pole. It is shown that this equation generalizes the Fourier law and Cattaneo equation of heat conduction, and it depends strongly on the relative values of the length and time scales compared with the mean-free path and mean-free time of the energy carriers, respectively. In the limiting case of steady-state heat conduction, it is shown that the heat flux vector depends on a spatial scale ratio whose effects are remarkable in the micro-scale spatial domains. By applying a first-order approximation of the obtained thermal Multipole expansion to the problem of transient heat conduction across a t...
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a constitutive equation for nano to macro scale heat conduction based on the boltzmann transport equation
Journal of Applied Physics, 2011Co-Authors: Jose Ordonezmiranda, Ronggui Yang, J J AlvaradogilAbstract:A constitutive equation for heat conduction is derived from the exact solution of the Boltzmann transport equation under the relaxation time approximation. This is achieved by a series expansion on multiple space derivatives of the temperature and introducing the concept of thermal Multipoles, where the thermal conductivity defined under the framework of the Fourier law of heat conduction is just the first thermal pole. It is shown that this equation generalizes the Fourier law and Cattaneo equation of heat conduction, and it depends strongly on the relative values of the length and time scales compared with the mean-free path and mean-free time of the energy carriers, respectively. In the limiting case of steady-state heat conduction, it is shown that the heat flux vector depends on a spatial scale ratio whose effects are remarkable in the micro-scale spatial domains. By applying a first-order approximation of the obtained thermal Multipole expansion to the problem of transient heat conduction across a thin film and comparing the results with the predictions for the same problem using the Fourier, Cattaneo and Boltzmann transport equations, it is shown that our results could be useful in the study of the heat transport in short as well as in long scales of space and time. The common and different features of the Multipole expansion compared with the Ballistic-diffusive model of heat conduction are also discussed. Special emphasis is put to the cases where the physical scales of space and time are comparable to the mean-free path and mean-free time of the energy carriers.
Ronggui Yang - One of the best experts on this subject based on the ideXlab platform.
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a constitutive equation for nano to macro scale heat conduction based on the boltzmann transport equation
Journal of Applied Physics, 2011Co-Authors: Jose Ordonezmiranda, Ronggui Yang, J J AlvaradogilAbstract:A constitutive equation for heat conduction is derived from the exact solution of the Boltzmann transport equation under the relaxation time approximation. This is achieved by a series expansion on multiple space derivatives of the temperature and introducing the concept of thermal Multipoles, where the thermal conductivity defined under the framework of the Fourier law of heat conduction is just the first thermal pole. It is shown that this equation generalizes the Fourier law and Cattaneo equation of heat conduction, and it depends strongly on the relative values of the length and time scales compared with the mean-free path and mean-free time of the energy carriers, respectively. In the limiting case of steady-state heat conduction, it is shown that the heat flux vector depends on a spatial scale ratio whose effects are remarkable in the micro-scale spatial domains. By applying a first-order approximation of the obtained thermal Multipole expansion to the problem of transient heat conduction across a t...
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a constitutive equation for nano to macro scale heat conduction based on the boltzmann transport equation
Journal of Applied Physics, 2011Co-Authors: Jose Ordonezmiranda, Ronggui Yang, J J AlvaradogilAbstract:A constitutive equation for heat conduction is derived from the exact solution of the Boltzmann transport equation under the relaxation time approximation. This is achieved by a series expansion on multiple space derivatives of the temperature and introducing the concept of thermal Multipoles, where the thermal conductivity defined under the framework of the Fourier law of heat conduction is just the first thermal pole. It is shown that this equation generalizes the Fourier law and Cattaneo equation of heat conduction, and it depends strongly on the relative values of the length and time scales compared with the mean-free path and mean-free time of the energy carriers, respectively. In the limiting case of steady-state heat conduction, it is shown that the heat flux vector depends on a spatial scale ratio whose effects are remarkable in the micro-scale spatial domains. By applying a first-order approximation of the obtained thermal Multipole expansion to the problem of transient heat conduction across a thin film and comparing the results with the predictions for the same problem using the Fourier, Cattaneo and Boltzmann transport equations, it is shown that our results could be useful in the study of the heat transport in short as well as in long scales of space and time. The common and different features of the Multipole expansion compared with the Ballistic-diffusive model of heat conduction are also discussed. Special emphasis is put to the cases where the physical scales of space and time are comparable to the mean-free path and mean-free time of the energy carriers.
Hiroaki Itou - One of the best experts on this subject based on the ideXlab platform.
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design of Multipole loudspeaker array based on spherical harmonic expansion
International Conference on Acoustics Speech and Signal Processing, 2011Co-Authors: Yoichi Haneda, Kenichi Furuya, Hiroaki ItouAbstract:We investigated the Multipole loudspeaker array based on spherical harmonic expansion in the Cartesian coordinate system. The arrangement of the Multipoles with the least number of loudspeaker units has been studied for 2nd order of spherical harmonic expansion. The directivity of the Multipole array does not achieve ideal directivity of the spherical functions due to the asymmetrical arrangement. The Multipole array was also applied to an end-fire array because a Multipole array uses less loudspeakers than the spherical array if the look-direction is fixed. We compared the performance of the conventional least-squares design method and Multipole array method for an end-fire array. The least squares method had a higher directivity due to the large number of variable coefficients. Nevertheless, the Multipole array based on spherical harmonic expansion has advantages of easy setup in the Cartesian coordinate system, analytical directivity, and small number of filter coefficients.
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ICASSP - Design of Multipole loudspeaker array based on spherical harmonic expansion
2011 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2011Co-Authors: Yoichi Haneda, Kenichi Furuya, Hiroaki ItouAbstract:We investigated the Multipole loudspeaker array based on spherical harmonic expansion in the Cartesian coordinate system. The arrangement of the Multipoles with the least number of loudspeaker units has been studied for 2nd order of spherical harmonic expansion. The directivity of the Multipole array does not achieve ideal directivity of the spherical functions due to the asymmetrical arrangement. The Multipole array was also applied to an end-fire array because a Multipole array uses less loudspeakers than the spherical array if the look-direction is fixed. We compared the performance of the conventional least-squares design method and Multipole array method for an end-fire array. The least squares method had a higher directivity due to the large number of variable coefficients. Nevertheless, the Multipole array based on spherical harmonic expansion has advantages of easy setup in the Cartesian coordinate system, analytical directivity, and small number of filter coefficients.
Yoichi Haneda - One of the best experts on this subject based on the ideXlab platform.
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directivity synthesis with Multipoles comprising a cluster of focused sources using a linear loudspeaker array
International Conference on Acoustics Speech and Signal Processing, 2018Co-Authors: Kimitaka Tsutsumi, Yoichi Haneda, Kenichi Noguchil, Hideaki TakadaAbstract:A method to create Multipoles comprising a cluster of focused sources by using a linear loudspeaker array has recently been investigated. Directivities in a listening area were confirmed with examples of primitive Multipoles such as dipoles and quadrupoles. This paper describes a method to create a sound source having more complex directivity by using a superposition of Multipoles comprising a collection of focused sources. An analytical method is also described with which coefficients can be obtained for each Multipole by circular harmonic expansion of a sound field created by a directional sound source and Taylor expansion of the corresponding sound field. Simulation results show that a superposition of Multipoles based on analytical conversion introduces desired directivities to the sound sources created in the listening area by a linear loudspeaker array.
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design of Multipole loudspeaker array based on spherical harmonic expansion
International Conference on Acoustics Speech and Signal Processing, 2011Co-Authors: Yoichi Haneda, Kenichi Furuya, Hiroaki ItouAbstract:We investigated the Multipole loudspeaker array based on spherical harmonic expansion in the Cartesian coordinate system. The arrangement of the Multipoles with the least number of loudspeaker units has been studied for 2nd order of spherical harmonic expansion. The directivity of the Multipole array does not achieve ideal directivity of the spherical functions due to the asymmetrical arrangement. The Multipole array was also applied to an end-fire array because a Multipole array uses less loudspeakers than the spherical array if the look-direction is fixed. We compared the performance of the conventional least-squares design method and Multipole array method for an end-fire array. The least squares method had a higher directivity due to the large number of variable coefficients. Nevertheless, the Multipole array based on spherical harmonic expansion has advantages of easy setup in the Cartesian coordinate system, analytical directivity, and small number of filter coefficients.
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ICASSP - Design of Multipole loudspeaker array based on spherical harmonic expansion
2011 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2011Co-Authors: Yoichi Haneda, Kenichi Furuya, Hiroaki ItouAbstract:We investigated the Multipole loudspeaker array based on spherical harmonic expansion in the Cartesian coordinate system. The arrangement of the Multipoles with the least number of loudspeaker units has been studied for 2nd order of spherical harmonic expansion. The directivity of the Multipole array does not achieve ideal directivity of the spherical functions due to the asymmetrical arrangement. The Multipole array was also applied to an end-fire array because a Multipole array uses less loudspeakers than the spherical array if the look-direction is fixed. We compared the performance of the conventional least-squares design method and Multipole array method for an end-fire array. The least squares method had a higher directivity due to the large number of variable coefficients. Nevertheless, the Multipole array based on spherical harmonic expansion has advantages of easy setup in the Cartesian coordinate system, analytical directivity, and small number of filter coefficients.
