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Journal articles on the topic 'Acoustic mode conversion'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

PALIES, P., D. DUROX, T. SCHULLER, and S. CANDEL. "Acoustic–convective mode conversion in an aerofoil cascade." Journal of Fluid Mechanics 672 (February 14, 2011): 545–69. http://dx.doi.org/10.1017/s0022112010006142.

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When an acoustic wave impinges on an aerofoil cascade, a convective vorticity mode is generated giving rise to transverse velocity perturbations. This mode conversion process is investigated to explain the flow dynamics observed when swirlers are submitted to incident acoustic disturbances. The phenomenon is first studied in the case of a two-dimensional aerofoil cascade using a model derived from an actuator disk theory. The model is simplified to deal with low-Mach-number flows. The velocity field on the downstream side of the cascade features two components, an axial perturbation associated

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2

Shivamoggi, Bhimsen K. "Resonant mode conversion of a shear Alfvén wave." Canadian Journal of Physics 65, no. 4 (1987): 357–58. http://dx.doi.org/10.1139/p87-041.

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A new mechanism for the resonant absorption of a shear Alfvén wave is proposed that involves a direct mode conversion of the latter to an ion-acoustic wave without bringing in the intermediary — the kinetic Alfvén wave. The fraction of the incident Alfvén-wave energy that is mode-converted to an ion-acoustic wave is calculated. This mechanism likely operates in the solar wind, where it might lead to heating of the plasma.

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Fernandes, Gil M., Nelson J. Muga, and Armando Nolasco Pinto. "Tunable Mode Conversion Using Acoustic Waves in Optical Microwires." Journal of Lightwave Technology 32, no. 19 (2014): 3257–65. http://dx.doi.org/10.1109/jlt.2014.2330955.

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4

Chean, Tan Wei, Naohiro Hozumi, Sachiko Yoshida, Kazuto Kobayashi, and Yuki Ogura. "Mutual conversion between B-mode image and acoustic impedance image." Japanese Journal of Applied Physics 56, no. 7S1 (2017): 07JF18. http://dx.doi.org/10.7567/jjap.56.07jf18.

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5

Bender, F., R. Dahint, and F. Josse. "Acoustic wave-based sensors using mode conversion in periodic gratings." IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 46, no. 6 (1999): 1497–503. http://dx.doi.org/10.1109/58.808873.

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6

Behme, G., and T. Hesjedal. "Reflection and mode conversion of surface acoustic waves studied by scanning acoustic force microscopy." Applied Physics A Materials Science & Processing 72, no. 4 (2001): 491–93. http://dx.doi.org/10.1007/s003390100803.

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7

Raboonik, Abbas, and Paul S. Cally. "Benchmarking hall-induced magnetoacoustic to Alfvén mode conversion in the solar chromosphere." Monthly Notices of the Royal Astronomical Society 507, no. 2 (2021): 2671–83. http://dx.doi.org/10.1093/mnras/stab2293.

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ABSTRACT A 2.5D numerical model of magnetoacoustic-Alfvén linear mode conversions in the partially ionized low solar atmosphere induced by the Hall effect is surveyed, varying magnetic field strength and inclination, and wave frequency and horizontal wavenumber. It is found that only the magnetic component of wave energy is subject to Hall-mediated conversions to Alfvén wave-energy via a process of polarization rotation. This strongly boosts direct mode conversion between slow magnetoacoustic and Alfvén waves in the quiet low chromosphere, even at mHz frequencies. However, fast waves there, wh

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8

Schmitt, M., K. Schmidt, S. Olfert, et al. "Detection of coatings within liquid-filled tubes and containers by mode conversion of leaky Lamb waves." Journal of Sensors and Sensor Systems 2, no. 1 (2013): 73–84. http://dx.doi.org/10.5194/jsss-2-73-2013.

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Abstract. In this paper, a new acoustic sensor principle for coating detection within liquid-filled tubes and containers based on mode conversion of leaky Lamb waves is introduced. Leaky Lamb waves are excited and detected by single-phase transducers, which are attached on the outer side of a tube or container. By transmission time and amplitude measurements, coating formation within the liquid-filled tube and container is detected non-invasively. This new sensor principle is subdivided into the separate considerations of Lamb wave excitation, mode conversion and inverse mode conversion. The L

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9

Riedl, J. M., T. Van Doorsselaere, and I. C. Santamaria. "Wave modes excited by photospheric p-modes and mode conversion in a multi-loop system." Astronomy & Astrophysics 625 (May 2019): A144. http://dx.doi.org/10.1051/0004-6361/201935393.

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Context. Waves are ubiquitous in the solar corona and there are indications that they are excited by photospheric p-modes. However, it is unclear how p-modes in coronal loops are converted to sausage modes and transverse (kink) modes, which are observed in the corona. Aims. We aim to investigate how those wave modes are excited in the lower corona by photospheric acoustic waves. Methods. We built 3D magnetohydrostatic loop systems with multiple inclinations spanning from the photosphere to the lower corona. We then simulated these atmospheres with the MANCHA code, in which we perturb the equil

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10

Draeger, Carsten, Didier Cassereau, and Mathias Fink. "Acoustic time reversal with mode conversion at a solid-fluid interface." Applied Physics Letters 72, no. 13 (1998): 1567–69. http://dx.doi.org/10.1063/1.121117.

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11

Kuo-ting Wu, M. Kobayashi, and Cheng-kuei Jen. "Integrated high-temperature piezoelectric plate acoustic wave transducers using mode conversion." IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 56, no. 6 (2009): 1218–24. http://dx.doi.org/10.1109/tuffc.2009.1163.

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12

Ouyang, Shiliang, Hailong He, Zhaojian He, Ke Deng, and Heping Zhao. "Acoustic one-way mode conversion and transmission by sonic crystal waveguides." Journal of Applied Physics 120, no. 10 (2016): 104504. http://dx.doi.org/10.1063/1.4962201.

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13

YI, GUO-JUN, KE-MIN LI, LI-MING TANG, and XIAO-HUA CHEN. "THE COMPARING OF ACOUSTIC PHONON TRANSPORT ABOUT MONOCHROMATIC MODE AND MIXING MODE THROUGH A DOUBLE T-SHAPED QUANTUM WAVEGUIDE." Modern Physics Letters B 25, no. 30 (2011): 2313–21. http://dx.doi.org/10.1142/s0217984911027522.

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We compare the thermal conductance of SH mode and mixing mode of acoustic phonons in a double T-shaped quantum waveguide at low enough temperatures by using the scattering-matrix method, and analyze the influence from mode conversion. Our results show that the small changes of the geometric parameters can induce different variation on the thermal conductivity, where the effect of the stub height of SH wave is the strongest. Moreover, the mode conversion plays an important role on the thermal conductivity, especially at the higher temperatures, and the coupling effect between two stubs at mixin

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14

Toda, Kohji, and Kohji Watabe. "Optical Modulation Using Mode Conversion from Surface Acoustic Wave to Bulk Wave." Japanese Journal of Applied Physics 24, S3 (1985): 162. http://dx.doi.org/10.7567/jjaps.24s3.162.

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15

Gusev, Vitalyi E. "Resonant mechanical meta-interface suppressing transmission of acoustic waves without mode conversion." Journal of Applied Physics 117, no. 5 (2015): 054903. http://dx.doi.org/10.1063/1.4906858.

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16

Qian, Jiao, Yin Wang, Jian-ping Xia, et al. "Broadband integrative acoustic asymmetric focusing lens based on mode-conversion meta-atoms." Applied Physics Letters 116, no. 22 (2020): 223505. http://dx.doi.org/10.1063/5.0004579.

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17

Sabri, S., S. Poedts, and H. Ebadi. "Plasma heating by magnetoacoustic wave propagation in the vicinity of a 2.5D magnetic null-point." Astronomy & Astrophysics 623 (March 2019): A81. http://dx.doi.org/10.1051/0004-6361/201834286.

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Context. Magnetohydrodynamic (MHD) waves have significant potential as a plasma heating mechanism. Finding a suitable wave dissipation mechanism is a very tough task, given the many observational constraints on the models, and this has resulted in the development of an important research community in solar physics. The magnetic field structure has an important role in the solar corona heating. Here, we investigate in detail current sheet mode generation via magnetic reconnection and mode conversion releases some of the free magnetic energy and produces heating. In addition, energy conversion i

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18

Kim, Noh Yu, and Cheol Kyou Lee. "Simultaneous Measurement of Longitudinal and Transverse Waves Velocities Employing Spherically Focused Acoustic Transducer." Key Engineering Materials 321-323 (October 2006): 574–77. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.574.

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Scanning acoustic microscopy (SAM) has been applied successfully to measure leaky surface wave(LSAW) velocity from V(z) curve for material characterization. Besides LSAW, SAM produces a variety of wave modes in the material propagating with different phase speeds and features, one of which is the mode-converted ultrasound. In this paper, a novel method for simultaneous measurement of longitudinal and transverse acoustic wave velocities using the mode-converted ultrasound is developed and studied at SAM. Each ultrasound arriving at the acoustic lens with different speed and phase (or time-of-fl

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19

Carlsson, Mats, and Thomas J. Bogdan. "Numerical modelling of MHD waves in the solar chromosphere." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1839 (2005): 395–404. http://dx.doi.org/10.1098/rsta.2005.1705.

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Acoustic waves are generated by the convective motions in the solar convection zone. When propagating upwards into the chromosphere they reach the height where the sound speed equals the Alfvén speed and they undergo mode conversion, refraction and reflection. We use numerical simulations to study these processes in realistic configurations where the wavelength of the waves is similar to the length scales of the magnetic field. Even though this regime is outside the validity of previous analytic studies or studies using ray-tracing theory, we show that some of their basic results remain valid:

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20

Kim, Noh Yu, and Sang Soon Lee. "Elastic Property Measurement of High-Tension Bolt Based on Mode Converted Ultrasound." Key Engineering Materials 326-328 (December 2006): 709–12. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.709.

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Elastic properties of high tension bolt are evaluated non-destructively by measuring acoustic longitudinal and shear wave velocities using mode-converted ultrasound. Mode-converted longitudinal and shear waves along bolt are captured to calculate acoustic wave velocities and determine elastic constants such as Young’s modulus and Bulk modulus based on acoustoelasticity. Ray analysis to select a specific mode conversion from longitudinal mode to shear mode is carried out and discussed with experimental results. From experiment results of maximum 5% of measurement error, it is shown that the pro

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21

Zhao, Hui, and Dean-Yi Chou. "MODE CONVERSION BETWEEN DIFFERENT RADIAL ORDERS FOR SOLAR ACOUSTIC WAVES SCATTERED BY SUNSPOTS." Astrophysical Journal 778, no. 1 (2013): 4. http://dx.doi.org/10.1088/0004-637x/778/1/4.

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22

Alshits, V. I., D. A. Bessonov, and V. N. Lyubimov. "Intensification of acoustic beams in crystals at mode conversion near total internal reflection." JETP Letters 106, no. 1 (2017): 40–45. http://dx.doi.org/10.1134/s0021364017130069.

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23

Tournat, V., V. E. Gusev, V. Yu Zaitsev, and B. Castagnède. "Acoustic second-harmonic generation with shear to longitudinal mode conversion in granular media." Europhysics Letters (EPL) 66, no. 6 (2004): 798–804. http://dx.doi.org/10.1209/epl/i2003-10264-2.

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24

Alan, Salih, Ahmed Allam, and Alper Erturk. "Programmable mode conversion and bandgap formation for surface acoustic waves using piezoelectric metamaterials." Applied Physics Letters 115, no. 9 (2019): 093502. http://dx.doi.org/10.1063/1.5110701.

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25

Wadbro, Eddie. "Analysis and design of acoustic transition sections for impedance matching and mode conversion." Structural and Multidisciplinary Optimization 50, no. 3 (2014): 395–408. http://dx.doi.org/10.1007/s00158-014-1058-2.

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26

Marsh, M. S., J. Ireland, and T. Kucera. "A Bayesian Analysis of MHD Waves in the Lower Atmosphere." Proceedings of the International Astronomical Union 3, S247 (2007): 48–54. http://dx.doi.org/10.1017/s1743921308014646.

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AbstractMagneto-hydrodynamic wave modes propagating from the solar photosphere into the corona have the potential to be exploited as an observational tool in an analogous way to the use of acoustic waves in helio/terrestrial seismology. In regions of strong magnetic field photospheric p-modes are thought to undergo mode conversion to slow magneto-acoustic waves, and that these slow magnetoacoustic p-modes may be waveguided from the photosphere into the solar corona along the magnetic field. A Bayesian analysis technique is applied to observations which suggests four distinct p-modes may be res

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27

Drexler, J., and J. P. St.-Maurice. "A possible origin for large aspect angle "HAIR'' echoes seen by SuperDARN radars in the E region." Annales Geophysicae 23, no. 3 (2005): 767–72. http://dx.doi.org/10.5194/angeo-23-767-2005.

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Abstract. Milan2004 have recently reported on close-range E region decameter size echoes that seem to be relatively weak, have apparently unusually large aspect angles, and possess Doppler shifts that are slow and are clearly consistent with the ion drift of the medium as opposed to, say, its electron drift or its ion-acoustic speed. We argue that these irregularities are the result of a nonlinear wave conversion process triggered by the nonlocal evolution of decameter Farley-Buneman waves. According to this picture, structures which have weak spontaneous growth rates and are initially field-a

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Elita Li, Yunyue, Yue Du, Jizhong Yang, Arthur Cheng, and Xinding Fang. "Elastic reverse time migration using acoustic propagators." GEOPHYSICS 83, no. 5 (2018): S399—S408. http://dx.doi.org/10.1190/geo2017-0687.1.

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Elastic wave imaging has been a significant challenge in the exploration industry due to the complexities in wave physics and numerical implementation. We have separated the governing equations for P- and S-wave propagation without the assumptions of homogeneous Lamé parameters to capture the mode conversion between the two body waves in an isotropic, constant-density medium. The resulting set of two coupled second-order equations for P- and S-potentials clearly demonstrates that mode conversion only occurs at the discontinuities of the shear modulus. Applying the Born approximation to the new

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29

Landskron, Johannes, Katrin Schmidt, Maria Kufner, and Gerhard Lindner. "Stable Vortex Generation in Liquid Filled Wells by Mode Conversion of Surface Acoustic Waves." Physics Procedia 70 (2015): 98–101. http://dx.doi.org/10.1016/j.phpro.2015.08.051.

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30

Qin, Feng, Bing Li, Lei Chen, and Zhongyu Shang. "Laser-induced surface acoustic waves for measurement of elastic constants based on mode conversion." Materials Chemistry and Physics 242 (February 2020): 122523. http://dx.doi.org/10.1016/j.matchemphys.2019.122523.

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31

Balakshy, Vladimir, Maxim Kupreychik, Sergey Mantsevich, and Vladimir Molchanov. "Acousto-Optic Cells with Phased-Array Transducers and Their Application in Systems of Optical Information Processing." Materials 14, no. 2 (2021): 451. http://dx.doi.org/10.3390/ma14020451.

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This paper presents the results of theoretical and experimental studies of anisotropic acousto-optic interaction in a spatially periodical acoustic field created by a phased-array transducer with antiphase excitation of adjacent sections. In this case, contrary to the nonsectioned transducer, light diffraction is absent when the optical beam falls on the phased-array cell at the Bragg angle. However, the diffraction takes place at some other angles (called “optimal” here), which are situated on the opposite sides to the Bragg angle. Our calculations show that the diffraction efficiency can rea

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32

Mukhin, Nikolay, and Ralf Lucklum. "Periodic Tubular Structures and Phononic Crystals towards High-Q Liquid Ultrasonic Inline Sensors for Pipes." Sensors 21, no. 17 (2021): 5982. http://dx.doi.org/10.3390/s21175982.

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The article focuses on a high-resolution ultrasound sensor for real-time monitoring of liquid analytes in cylindrical pipes, tubes, or capillaries. The development of such a sensor faces the challenges of acoustic energy losses, including dissipation at liquid/solid interface and acoustic wave radiation along the pipe. Furthermore, we consider acoustic resonant mode coupling and mode conversion. We show how the concept of phononic crystals can be applied to solve these problems and achieve the maximum theoretically possible Q-factor for resonant ultrasonic sensors. We propose an approach for e

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Sarkar, Jit, Swarniv Chandra, and Basudev Ghosh. "Resonant interactions between the fundamental and higher harmonic of positron acoustic waves in quantum plasma." Zeitschrift für Naturforschung A 75, no. 10 (2020): 819–24. http://dx.doi.org/10.1515/zna-2020-0012.

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AbstractIn this paper, we study the second harmonic generation and its interaction with the fundamental mode in a magnetised dense positron-ion plasma interacting with laser pulses. It has been shown that different harmonics propagate with different phase velocities. The gradual evolution of the fundamental wave into higher harmonics is studied, and the conversion efficiency is calculated. Dependence of conversion efficiency on wavenumber shifts and the applied magnetic field has also been examined.

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Rahaman, Ashiqur, Haeil Jung, and Byungki Kim. "Coupled D33 Mode-Based High Performing Bio-Inspired Piezoelectric MEMS Directional Microphone." Applied Sciences 11, no. 3 (2021): 1305. http://dx.doi.org/10.3390/app11031305.

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Microelectromechanical system (MEMS) directional microphones have been identified as having use in multi-projected virtual reality applications such as virtual meetings for projecting cameras. In these applications, the acoustic sensitivity plays a vital role as it biases the directional sensing, signal-to-noise ratio (SNR) and self-noise. The acoustic sensitivity is the multiplied outcome of the mechanical sensitivity and the electrical sensitivity. As the dimensions are limited in MEMS technology, the improvement of the acoustic sensitivity by reflecting the mechanical as well as electrical

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35

Ko, Dae-Sik. "Multiple-Transducer Scheme for Scanning Tomographic Acoustic Microscopy Using Transverse Waves." Ultrasonic Imaging 19, no. 4 (1997): 294–304. http://dx.doi.org/10.1177/016173469701900405.

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We propose a new type of multiple-transducer scheme with functions of multiple-angle and multiple-frequency tomography for scanning tomographic acoustic microscopy (STAM) using transverse waves. We review the data acquisition system and mode conversion of the acoustic waves for STAM and the multiple-angle and multiple-frequency tomography. Our multiple-transducer scheme has three insonification angles and three resonance frequencies in order to operate, in the transverse wave mode, multiple-angle and multiple frequency tomography for STAM. In order to evaluate the performance of our transducer

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36

Barroso-Romero, Maria, Daniel Gagar, Shashank Pant, and Marcias Martinez. "Wave Mode Identification of Acoustic Emission Signals Using Phase Analysis." Acoustics 1, no. 2 (2019): 450–72. http://dx.doi.org/10.3390/acoustics1020026.

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Acoustic Emission (AE) monitoring can be used to detect and locate structural damage such as growing fatigue cracks. The accuracy of damage location and consequently the inference of its significance for damage assessment is dependent on the wave propagation properties in terms of wave velocity, dispersion, attenuation and wave mode conversion. These behaviors are understood and accounted for in simplistic structures; however, actual structures are geometrically complex, with components comprising of different materials. One of the key challenges in such scenarios is the ability to positively

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Shannon, K., X. Li, Z. Wang, and J. D. N. Cheeke. "Mode conversion and the path of acoustic energy in a partially water-filled aluminum tube." Ultrasonics 37, no. 4 (1999): 303–7. http://dx.doi.org/10.1016/s0041-624x(99)00006-2.

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38

Kharel, Prashanta, Glen I. Harris, Eric A. Kittlaus, et al. "High-frequency cavity optomechanics using bulk acoustic phonons." Science Advances 5, no. 4 (2019): eaav0582. http://dx.doi.org/10.1126/sciadv.aav0582.

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To date, microscale and nanoscale optomechanical systems have enabled many proof-of-principle quantum operations through access to high-frequency (gigahertz) phonon modes that are readily cooled to their thermal ground state. However, minuscule amounts of absorbed light produce excessive heating that can jeopardize robust ground-state operation within these microstructures. In contrast, we demonstrate an alternative strategy for accessing high-frequency (13 GHz) phonons within macroscopic systems (centimeter scale) using phase-matched Brillouin interactions between two distinct optical cavity

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39

Rekhy, Anuj, Robert Snyder, and James Manimala. "On the Frequency Up-Conversion Mechanism in Metamaterials-Inspired Vibro-Impact Structures." Acoustics 1, no. 1 (2019): 156–73. http://dx.doi.org/10.3390/acoustics1010011.

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Conventional acoustic absorbers like foams, fiberglass or liners are used commonly in structures for industrial, infrastructural, automotive and aerospace applications to mitigate noise. However, these have limited effectiveness for low-frequencies (LF, <~500 Hz) due to impractically large mass or volume requirements. LF content being less evanescent is a major contributor to environmental noise pollution and induces undesirable structural responses causing diminished efficiency, comfort, payload integrity and mission capabilities. There is, therefore a need to develop lightweight, compact,

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40

O’Brien, John, and Ron Harris. "Multicomponent VSP imaging of tight-gas sands." GEOPHYSICS 71, no. 6 (2006): E83—E90. http://dx.doi.org/10.1190/1.2335646.

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Low-porosity Bossier and Cotton Valley sands of the East Texas Basin, U. S., have only a small acoustic impedance contrast with the encasing shales but a greater relative contrast in shear-wave impedance. Vertical seismic profile (VSP) data acquired with both a near-offset and far-offset P-wave source clearly demonstrate the P-P reflectivity and P-S mode conversions within the Bossier section. We designate conventional P-wave reflectivity as P-P, shear-wave reflectivity as S-S, and P-wave/shear-wave mode conversion data as P-S. While Bossier P-P reflectivity is low, it appears to be adequate f

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Lee, Jin Kyung, Sang Ll Lee, Joon Hyun Lee, and Young Chul Park. "Propagation Characteristic of Elastic Wave in Pipe." Key Engineering Materials 345-346 (August 2007): 1323–26. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1323.

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In this study, elastic waves of ultrasonic and acoustic emission were used to evaluate the propagation characteristic of the wave in pipe, and study on mode conversion of the elastic wave due to the cracks in the pipe was also performed. An acoustic emission (AE) sensor was used to receive the propagated ultrasonic wave. AE technique has a merit that it can identify the received ultrasonic wave by the analysis of the AE parameters such as count, energy, frequency, duration time and amplitude. For transmitting and receiving of the wave, a wedge for universal angle was manufactured. The optimum

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42

Cally, P. S. "Dispersion relations, rays and ray splitting in magnetohelioseismology." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1839 (2005): 333–49. http://dx.doi.org/10.1098/rsta.2005.1702.

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Local helioseismology seeks to probe the near surface regions of the Sun, and in particular of active regions. These are distinguished by their strong magnetic fields, yet current local techniques do not take proper account of this. Here, we first derive appropriate gravito-magneto-acoustic dispersion relations, and then use these to examine how acoustic rays entering regions of strong field split into fast and slow components, and the subsequent fates of each. Specifically, two types of transmission point, where wave energy can transfer from the fast to slow branch (or vice versa) are identif

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Abrahamyan, A. S., and R. Yu Chilingaryan. "CONTROL OF CO2 LASER POWER BY ACOUSTIC FIELDS." Resource-Efficient Technologies, no. 1 (April 29, 2019): 27–34. http://dx.doi.org/10.18799/24056537/2019/1/229.

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The present study investigates the optimization of the operation of the CO2 laser in the acoustoplasma mode (i.e., dependence of the laser radiation power on the composition of the working mixture, pressure, value of the direct component of the discharge current, frequency, and modulation depth). A three-dimensional dependence on the frequency and modulation depth of the discharge current is experimentally obtained for the normalized efficiency of the conversion of the electric power supplied to the discharge tube into laser power. The maximum gain when transition to the acoustoplasma mode exc

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44

Бурдин, Д. А., P. Hayes, Н. А. Экономов, Д. В. Чашин та Ю. К. Фетисов. "Высокочастотный резонансный магнитоэлектрический эффект в структуре FeCoSiB-AlN на диэлектрической подложке". Письма в журнал технической физики 47, № 5 (2021): 35. http://dx.doi.org/10.21883/pjtf.2021.05.50675.18586.

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A high-frequency magnetoelectric (ME) effect has been discovered in a planar structure containing a ferromagnetic FeCoSiB layer and a piezoelectric AlN layer produced by magnetron sputtering on a borosilicate glass substrate. The structure was excited by a magnetic field at a frequency of the thickness acoustic vibration mode of 32.4 MHz, and the electric voltage generated by the piezoelectric layer was measured. The coefficient of ME conversion at the frequency of the second thickness mode is αE ≈ 19 V / A at a bias magnetic field of 120 A / m, corresponding to the maximum of the piezomagneti

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45

Snow, B., and A. Hillier. "Mode conversion of two-fluid shocks in a partially-ionised, isothermal, stratified atmosphere." Astronomy & Astrophysics 637 (May 2020): A97. http://dx.doi.org/10.1051/0004-6361/202037848.

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Context. The plasma of the lower solar atmosphere consists of mostly neutral particles, whereas the upper solar atmosphere is mostly made up of ionised particles and electrons. A shock that propagates upwards in the solar atmosphere therefore undergoes a transition where the dominant fluid is either neutral or ionised. An upwards propagating shock also passes a point where the sound and Alfvén speed are equal. At this point the energy of the acoustic shock can separated into fast and slow components. The way the energy is distributed between the two modes depends on the angle of magnetic field

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46

Landsberger, B. J., M. F. Hamilton, and Yu A. Il’insky. "Transmitted beam distortion and rotation due to mode conversion between acoustic and shear waves at liquid–solid interfaces." Journal of the Acoustical Society of America 96, no. 5 (1994): 3338. http://dx.doi.org/10.1121/1.410666.

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Xu, Huiping, Sulei Fu, Rongxuan Su, et al. "Enhanced Coupling Coefficient in Dual-Mode ZnO/SiC Surface Acoustic Wave Devices with Partially Etched Piezoelectric Layer." Applied Sciences 11, no. 14 (2021): 6383. http://dx.doi.org/10.3390/app11146383.

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Surface acoustic wave (SAW) devices based on multi-layer structures have been widely used in filters and sensors. The electromechanical coupling factor (K2), which reflects energy-conversion efficiency, directly determines the bandwidth of the filter and the sensitivity of sensor. In this work, a new configuration of dual-mode (quasi-Rayleigh and quasi-Sezawa) SAW devices on a ZnO/SiC layered structure exhibiting significantly enhanced K2 was studied using the finite element method (FEM), which features in the partial etching of the piezoelectric film between the adjacent interdigitated electr

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Wang, Weixin, Xiling Liu, Xiongbing Li, Gang Xu, and Shuzeng Zhang. "Modeling Flaw Pulse-Echo Signals in Cylindrical Components Using an Ultrasonic Line-Focused Transducer with Consideration of Wave Mode Conversion." Sensors 19, no. 12 (2019): 2744. http://dx.doi.org/10.3390/s19122744.

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Investigations on flaw responses can benefit the nondestructive testing of cylinders using line-focused transducers. In this work, the system function, the wave beam model, and a flaw scattering model are combined to develop an ultrasonic measurement model for line-focused transducers to predict flaw responses in cylindrical components. The system function is characterized using reference signals by developing an acoustic transfer function for line-focused transducers, which works at different distances for both planar and curved surfaces. The wave beams in cylindrical components are modeled u

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Hamood, Ahmed, Artur J. Jaworski, and Xiaoan Mao. "Development and Assessment of Two-Stage Thermoacoustic Electricity Generator." Energies 12, no. 9 (2019): 1790. http://dx.doi.org/10.3390/en12091790.

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This paper presents the development and assessment of a two-stage thermoacoustic electricity generator that aims to mimic the conversion of waste heat from the internal combustion engine exhaust gases into useful electricity. The one wavelength configuration consists of two identical stages which allow coupling a linear alternator in a “push-pull” mode because of the 180° out of phase acoustic excitation on two sides of the piston. This type of coupling is a possible solution for the low acoustic impedance of looped-tube traveling-wave thermoacoustic engines. The experimental set-up is 16.1 m

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Diab, Daher, Nikolay Smagin, Fabrice Lefebvre, et al. "Broadband Vibrational Energy Harvesting with a Spherical Piezoelectric Transducer Devoted to Underwater Wireless Sensor Networks." Acta Acustica united with Acustica 105, no. 4 (2019): 616–29. http://dx.doi.org/10.3813/aaa.919342.

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A new sensing node container based on a spherical piezoelectric transducer is proposed. This device provides broadband vibrational energy harvesting and sensing facilities intended for underwater wireless sensor networks. The transducer is composed of two acrylic glass (PMMA) half-spherical shells and a Pz26 piezoelectric ring clamped between the two shells. A simulation model of vibrational energy harvesting has been developed with electromechanical circuits for thickness and radial vibrational modes. This approach was validated by a finite element simulation. As a result, optimal power harve

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