Acoustic wave confinement in two-dimensional phononic crystal with multiple nested resonators

In this research, a novel phononic crystal (PC) is investigated theoretically to enhance acoustic pressure confinement. It consists of multiple nested resonators based on a tapered configuration. Nested phononic crystal resonator (NPCR) can enhance the acoustic pressure amplification at resonant cavity to a great degree better than the traditional one with same dimensions. The resonant frequency of NPCR is mainly located within outermost phononic crystal resonator’s (PCR) band gap. Meanwhile, it does not move significantly to high frequency with the addition of inner tapered resonators. The enhanced acoustic pressure resonant amplification is attributed to the improvement of the confinement mode owing to the nested structure working as a taper. Then effects of geometrical dimensions of inner PCRs on acoustic confinement are studied. It shows that resonant frequency and resonant acoustic pressure can be affected by the geometric parameters. NPCR has stronger acoustic confinement effects, which are conducive to improve acoustic sensing sensitivity, acoustic signal frequency resolution and acoustic energy harvesting efficiency.

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Acoustic energy harvesting based on the topological interface mode of 1D phononic crystal tube

Applied Physics Express ◽

10.7567/1882-0786/ab5ff8 ◽

2019 ◽

Vol 13 (1) ◽

pp. 017004

Author(s):

Lei Fan ◽

Ye He ◽

Xiao-an Chen ◽

Xue Zhao

Keyword(s):

Energy Harvesting ◽

Phononic Crystal ◽

Acoustic Energy ◽

Acoustic Energy Harvesting ◽

Interface Mode

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Acoustic energy harvesting from vortex-induced tonal sound in a baffled pipe

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406211406017 ◽

2011 ◽

Vol 225 (8) ◽

pp. 1847-1850 ◽

Cited By ~ 3

Author(s):

R Hernandez ◽

S Jung ◽

K I Matveev

Keyword(s):

Acoustic Pressure ◽

Electrical Energy ◽

High Amplitude ◽

Acoustic Mode ◽

Acoustic Energy ◽

Electric Load ◽

Mean Flow ◽

Acoustic Resonators ◽

Acoustic Energy Harvesting ◽

Mean Flow Velocity

Energy of high-amplitude sound that often appears in acoustic resonators with mean flow can be harnessed and converted into electricity for powering sensors and other devices. In this study, tests were conducted in a simple setup consisting of a pipe with a pair of baffles and a piezoelement. Tonal sound, corresponding to the second acoustic mode of the resonator, was excited due to vortex shedding/impinging on baffles in the presence of mean flow. Generated sound energy was partially converted into electrical energy by a piezoelement. About 0.55 mW of electric power was produced on a resistive electric load at acoustic pressure amplitudes in the pipe about 170 Pa and mean flow velocity 2.6 m/s.

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Acoustic energy harvesting using resonant cavity of a sonic crystal

Applied Physics Letters ◽

10.1063/1.3176019 ◽

2009 ◽

Vol 95 (1) ◽

pp. 013506 ◽

Cited By ~ 117

Author(s):

Liang-Yu Wu ◽

Lien-Wen Chen ◽

Chia-Ming Liu

Keyword(s):

Energy Harvesting ◽

Resonant Cavity ◽

Acoustic Energy ◽

Sonic Crystal ◽

Acoustic Energy Harvesting

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Acoustic Energy Harvesting Using Quarter-Wavelength Straight-Tube Resonator

Volume 12: Vibration, Acoustics and Wave Propagation ◽

10.1115/imece2012-86989 ◽

2012 ◽

Cited By ~ 6

Author(s):

Bin Li ◽

Andrew J. Laviage ◽

Jeong Ho You ◽

Yong-Joe Kim

Keyword(s):

Energy Harvesting ◽

Pressure Gradient ◽

Acoustic Pressure ◽

Acoustic Energy ◽

Straight Tube ◽

Single Beam ◽

Energy Harvesters ◽

Resonant Wave ◽

Quarter Wavelength ◽

Acoustic Energy Harvesting

Although there have been significant efforts in harvesting environmental energy, our environment is still full of wasted and unused energy. As clean, ubiquitous and sustainable energy source, acoustic energy is one of the wasted energies and is abundant in our life. Therefore, it is of great interest to investigate acoustic energy harvesting mechanism as an alternative to existing energy harvesters. In this study, in order to harvest acoustic energy, piezoelectric cantilever beams are placed inside a quarter-wavelength straight-tube resonator. When the straight-tube resonator is excited by an incident wave at its acoustic eigenfrequency, an amplified acoustic resonant wave is developed inside the tube and drives the vibration motion of the piezoelectric beams. The piezoelectric beams have been designed to have the same structural eigenfrequency as the acoustic eigenfrequency of the tube resonators to maximize the amount of the harvested energy. With a single beam placed inside the tube resonators, the harvested voltage and power become the maximum near the tube open inlet where the acoustic pressure gradient is at the maximum. As the beam is moved to the tube closed end, the voltage and power gradually decrease due to the decreased acoustic pressure gradient. Multiple piezoelectric beams have been placed along the centerline of the tube resonators in order to increase the amount of harvested energy. Due to the interruption of acoustic air particle motion caused by the beams, it is found that placing piezoelectric beams near the closed tube end is not beneficial. The output voltage of the piezoelectric beams increases linearly as the incident sound pressure increases.

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Highly directional acoustic wave radiation based on asymmetrical two-dimensional phononic crystal resonant cavity

Applied Physics Letters ◽

10.1063/1.2217923 ◽

2006 ◽

Vol 88 (26) ◽

pp. 263505 ◽

Cited By ~ 35

Author(s):

Manzhu Ke ◽

Zhengyou Liu ◽

Pei Pang ◽

Wengang Wang ◽

Zhigang Cheng ◽

...

Keyword(s):

Acoustic Wave ◽

Phononic Crystal ◽

Resonant Cavity ◽

Wave Radiation ◽

Two Dimensional

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Does tinnitus originate from hyperactive nerve fibers in the cochlea?

The Journal of Laryngology & Otology ◽

10.1017/s1755146300090090 ◽

1984 ◽

Vol 98 (S9) ◽

pp. 38-44 ◽

Cited By ~ 5

Author(s):

Richard S. Tyler

Keyword(s):

Basilar Membrane ◽

Tuning Curve ◽

Nerve Fibers ◽

Frequency Resolution ◽

Signal Frequency ◽

Physiological Data ◽

Pitch Matching ◽

Category Scaling ◽

Tinnitus Masking ◽

Peripheral Origin

AbstractThis paper discusses the possibility of a localized peripheral origin of tinnitus. A working hypothesis is that tinnitus represents either aperiodic or periodic hyperactivity in the spontaneous activity of nerve fibers originating from a restricted place on the basilar membrane. The limited physiological data available support both hyperactive and hypoactive nerve fiber. Psychophysical data are not easy to interpret. Subjective descriptions and category scaling are too dependent on individual experience. Pitch matching can be reliable, but cannot distinguish between peripheral or central tinnitus. In one experiment we compared the masking of tinnitus to the masking of a pure tone, where the signal frequency and level were obtained from the tinnitus pitch and loudness matching. The results indicate that the broad tinnitus masking patterns are not typically due to the poor frequency resolution observed in sensorineural hearing loss. However, in a few subjects there was some correspondence between the shape of the tuning curve and the tinnitus masking pattern. In another study, we masked tinnitus with narrowband noises of different bandwidths. In some patients, there was a ‘critical bandwidth’ effect; wider masker bandwidths required greater overall sound pressures to mask the tinnitus. We conclude that the results from these studies taken together indicate that there are different types of tinnitus, some of which may have a localized peripheral origin.

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The effect of type of sound damper material in the Helmholtz resonator to the output power spectrum of acoustic energy Harvester

Journal of Physics Theories and Applications ◽

10.20961/jphystheor-appl.v3i2.38148 ◽

2019 ◽

Vol 3 (2) ◽

pp. 50

Author(s):

Hedwigis Harindra ◽

Agung Bambang Setio Utomo ◽

Ikhsan Setiawan

Keyword(s):

Energy Harvesting ◽

Power Spectrum ◽

Electric Power ◽

Energy Harvester ◽

Helmholtz Resonator ◽

Acoustic Energy ◽

Acoustic Energy Harvesting ◽

Wasted Energy ◽

Second Peak ◽

Output Electric Power

Acoustic energy harvesting is one of many ways to harness acoustic noises as wasted energy into useful electical energy using an acoustic energy harvester. Acoustic energy harvester that tested by Dimastya (2018) which is consisted of loudspeaker and Helmholtz resonator, produced two-peak spectrum. It is suspected that the first peak is due to Helmholtz resonator resonance and the second peak comesfrom the resonance of the conversion loudspeaker. This research is to experimentally confirm the guess of the origin of the first peak. The experiments are performed by adding silencer materials on the resonator inner wall which are expected to be able to reduce the height of first peak and to know how they affect the output electric power spectrum of the acoustic energy harvester. Three different silencer materials are used, those are glasswool, acoustic foam, and styrofoam, with the same thickness of 12 cm. The results show that glasswool absorbs sound more effectively than acostic foam and styrofoam. The use of glasswool, acoustic foam, and styrofoam with 12 cm thickness lowered the first peak by 90% (from 39 mW to 0,5 mW), 82% (from 39 mW to 0,7 mW), and 82% (from 39 mW to 0,7 mW), respectively. Based on these results, it is concluded that the guess of the origin of the first peak is confirmed.

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Design of DDS Based on FPGA Technology

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.713-715.1031 ◽

2015 ◽

Vol 713-715 ◽

pp. 1031-1033

Author(s):

Wei Jiang ◽

Fang Yuan ◽

Liu Qing Yang

Keyword(s):

High Frequency ◽

Simple Structure ◽

Frequency Synthesizer ◽

Sine Wave ◽

Lookup Table ◽

Frequency Resolution ◽

Signal Frequency ◽

Small Delay ◽

Working Principle ◽

Output Only

This paper introduces the working principle and structure of direct digital frequency synthesizer. This paper select the technology of lookup table to design DDS because it has many advantages such as less consumption hardware resources, simple structure, output only small delay and so on. As a result, signal generator can produce many waveforms with good stability and high frequency resolution. Finally, test showed that the output wave of triangular signal frequency is greater than 1MHz and the highest sine wave frequency is 30MHz, the value of peak to peak is continuously adjustable in 50mV ~ 4V range. The result of study will provide theoretical guidance for the design of DDS.

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