scholarly journals Research on the characteristics of Klein–Cook parameter and diffraction efficiency of acousto-optic interaction for low-frequency ultrasonic in the liquid

2021 ◽  
Vol 51 (3) ◽  
Author(s):  
Jing Gao ◽  
Guang Han ◽  
Jianzhuo Zhu
Keyword(s):  
Wave Equation ◽  
Small Parameter ◽  
Water Temperature ◽  
Theoretical Basis ◽  
Sucrose Solution ◽  
Low Frequency ◽  
Normal Incidence ◽  
Ultrasonic Frequency ◽  
Interaction Length ◽  
Acousto Optic Interaction

We have investigated the characteristics of acousto-optic interaction for low-frequency ultrasonic wave in a liquid. Based on the coupling wave equation of acousto-optic interaction, the diffraction light characteristics for normal incidence at small parameter Q have been discussed. The parameter Q with respect to acousto-optic interaction length, ultrasonic frequency, water temperature, and the concentration of sucrose solution have been analyzed, which is an important physical quantity and reflects the degree of mismatch in the acousto-optic interaction. The diffraction efficiencies for different parameters Q, incident angles and phase shifts have been calculated. The results of our work provide theoretical basis for further study of the acousto-optic effect in the liquid.

Optimization of Chlorella pyrenoidosa Removal by Low Frequency Ultrasonic Irradiation Using Response Surface Design

2011 ◽  
Vol 295-297 ◽  
pp. 1860-1865 ◽  
Author(s):  
Zhi Zhang ◽  
Chao Liu ◽  
Gong Duan Fan ◽  
Jing Luo ◽  
Yan Dong Wang
Keyword(s):  
Response Surface ◽  
Irradiation Time ◽  
Removal Rate ◽  
Low Frequency ◽  
Chlorella Pyrenoidosa ◽  
Ultrasonic Frequency ◽  
Ultrasonic Power ◽  
Control Parameters ◽  
Single Factor ◽  
Surface Design

The control parameters of the removal of Chlorella pyrenoidosa, which was irradiated by low frequency ultrasonic, is optimized by using single factor experiments and response surface methodology (RSM). First of all, the approximate ranges of the ultrasonic frequency, the ultrasonic power and the irradiation time were estimated with single factor experiments for the further experiments. And then the optimized values of the three control parameters were determined, which were analyzed by using central composite design (CCD) and RSM. The results showed that the removal rate of chlorophyll-a could reach to 64.1% after the irradiation for 6.34min by using ultrasonic of 77.7 kHz and 250W. Ultrasonic technology can remove Chlorella pyrenoidosa cells in water quickly and effectively, so as to achieve the purpose of water purification.

scholarly journals On a Nonlinear Wave Equation of Kirchhoff-Carrier Type: Linear Approximation and Asymptotic Expansion of Solution in a Small Parameter

2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Nguyen Huu Nhan ◽  
Le Thi Phuong Ngoc ◽  
Nguyen Thanh Long
Keyword(s):  
Asymptotic Expansion ◽  
Wave Equation ◽  
Weak Solution ◽  
Dirichlet Problem ◽  
Small Parameter ◽  
Nonlinear Wave ◽  
Nonlinear Wave Equation ◽  
Existence And Uniqueness ◽  
Linearization Method ◽  
Asymptotic Expansion Of Solution

We consider the Robin-Dirichlet problem for a nonlinear wave equation of Kirchhoff-Carrier type. Using the Faedo-Galerkin method and the linearization method for nonlinear terms, the existence and uniqueness of a weak solution are proved. An asymptotic expansion of high order in a small parameter of a weak solution is also discussed.

Low-frequency noise control using layered granular aerogel and limp porous media

2021 ◽  
Vol 263 (4) ◽  
pp. 2724-2729
Author(s):  
Yutong Xue ◽  
Amrutha Dasyam ◽  
J. Stuart Bolton ◽  
Bhisham Sharma
Keyword(s):  
Noise Control ◽  
Glass Fibers ◽  
Low Frequency ◽  
Normal Incidence ◽  
Frequency Noise ◽  
Fibrous Materials ◽  
Low Frequency Noise ◽  
Frequency Range ◽  
Fibrous Media ◽  
Impedance Tube Method

The acoustic absorption of granular aerogel layers with a granule sizes in the range of 2 to 40 μm is dominated by narrow-banded, high absorption regions in the low-frequency range and by reduced absorption values at higher frequencies. In this paper, we investigate the possibility of developing new, low-frequency noise reduction materials by layering granular aerogels with traditional porous sound absorbing materials such as glass fibers. The acoustic behavior of the layered configurations is predicted using the arbitrary coefficient method, wherein the granular aerogel layers are modeled as an equivalent poro-elastic material while the fibrous media and membrane are modeled as limp media. The analytical predictions are verified using experimental measurements conducted using the normal incidence, two-microphone impedance tube method. Our results show that layered configurations including granular aerogels, fibrous materials, and limp membranes provide enhanced sound absorption properties that can be tuned for specific noise control applications over a broad frequency range.

Low Frequency Absorption of Additively Manufactured Cylinders

2019 ◽  
Author(s):  
Sophie R. Kaye ◽  
Ethan D. Casavant ◽  
Paul E. Slaboch
Keyword(s):  
Low Frequency ◽  
Normal Incidence ◽  
Frequency Noise ◽  
Outer Diameter ◽  
Acoustic Absorption ◽  
Frequency Range ◽  
Large Space ◽  
Low Frequencies ◽  
Cylinder Length ◽  
Hollow Cylinders

Abstract Attenuating low frequencies is often problematic, due to the large space required for common absorptive materials to mitigate such noise. However, natural hollow reeds are known to effectively attenuate low frequencies while occupying relatively little space compared to traditional absorptive materials. This paper discusses the effect of varied outer diameter, and outer spacing on the 200–1600 Hz acoustic absorption of additively manufactured arrays of hollow cylinders. Samples were tested in a 10 cm diameter normal incidence impedance tube such that cylinder length was oriented perpendicular to the incoming plane wave. By varying only one geometric element of each array, the absorption due to any particular parameter can be assessed individually. The tests confirmed the hypothesis that minimizing cylinder spacing and maximizing cylinder diameter resulted in increased overall absorption and produced more focused absorption peaks at specific low frequencies. Wider cylinder spacing produced a broader absorptive frequency range, despite shifting upward in frequency. Thus, manipulating these variables can specifically target absorption for low frequency noise that would otherwise disturb listeners.

Approximate symmetry analysis of nonlinear Rayleigh-wave equation

2018 ◽  
Vol 15 (04) ◽  
pp. 1850055
Author(s):  
Saeede Rashidi ◽  
S. Reza Hejazi ◽  
Elham Dastranj
Keyword(s):  
Wave Equation ◽  
Power Series ◽  
Small Parameter ◽  
Conservation Laws ◽  
Rayleigh Wave ◽  
Symmetry Analysis ◽  
Approximate Symmetry ◽  
Series Method ◽  
Power Series Method ◽  
New Exact Solutions

In this paper, the Lie approximate symmetry analysis is applied to investigate the new exact solutions of the Rayleigh-wave equation. The power series method is employed to solve some of the obtained reduced ordinary differential equations with a small parameter. We yield the new analytical solutions with small parameter which is effectively obtained by the proposed method. The concept of nonlinear self-adjointness is used to construct the conservation laws for Rayleigh-wave equation. It is shown that this equation is approximately nonlinearly self-adjoint and therefore desired conservation laws can be found using appropriate formal Lagrangians.

Acoustic Band Gap Extension in One-Dimensional Solid/Fluid Phononic Crystal Heterostructure

2014 ◽  
Vol 22 (04) ◽  
pp. 1450010 ◽  
Author(s):  
Xu Yang Xiao ◽  
Run Ping Chen
Keyword(s):  
Band Gap ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Wide Band ◽  
Normal Incidence ◽  
Wide Band Gap ◽  
Longitudinal Waves ◽  
One Dimensional ◽  
Solid Media ◽  
Fluid Media

The propagation of elastic longitudinal waves in one-dimensional (1D) phononic crystals (PNCs) consisting of alternating solid and fluid media is comprehensively analyzed in theory. We demonstrate the acoustic band gap (ABG) structure determined by the dispersion relation for longitudinal waves at normal incidence. According to the band structure, we design a sub-PNC by setting a reasonable thickness ratio of fluid and solid media, and then form a phononic heterostructure by merging this PNC and other PNC designed in advance. We have shown that the wide band gap exists in such a phononic heterostructure for elastic longitudinal waves at normal incidence. For oblique incidence, the wide band gap shifts towards high frequency regions, meanwhile a low-frequency band gap is split.

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