Frequency Acoustic Waves Research Articles

FEATURES OF THE INFLUENCE OF CLASSICAL MUSIC ON THE FORMATION OF THE PERSONALITY OF CHILDREN

Nowadays the problem of music impact has turned to be more complicated and it has obtained a special meaning since the music perception has become of a massive and day-to-day character in modern society, where the entertaining part of music has got the priority. The positive impact of classical music on children has been proved by scientists who affirm that a certain frequency of classical music acoustic waves affect the children satisfaction centers and facilitate mental activity development. The music impact on versatile progress of personality development are ensured by close interrelation of aesthetic, moral, mental and physical education that can be achieved being provided by the usage of all professional forms of children music activity organization. The article investigates the process of the influence of classical music on the formation of the child's personality at the present stage of the development of science. The problem of music perception psychology through the analyses of one of the types of musical activities legitimacy (music perception that is linked not only with the peculiarities of the music, as it is, its language, but with the deep knowledge about human’s nature, his/her features) has been examined. The aim of the article is to study either positive or negative music impact; to examine the music impact on the process of children’s personality formation; to create the proper picture reflecting the process of music and man cooperation; to find out individual peculiarities and conditions of proper music perception. The some questions of child’s individuality music development have been highlighted. The attempt to examine the alternative methods of the preschoolers’ music education that will have a positive effect on emotional and physical state has been made in the article. The results of the research open a great perspective for further investigation of the music perception and psychological impact as the phenomenon of the dynamic development that has its own structure and the system of determination. Practical significance of the work is that the results of the research can be the base for creation of new effective methods of music therapy impact.

Study of Working Medium Performance by Acoustic Emission in EDM Machining of Ti6Al4V

In electrical discharge machining (EDM), the working medium plays an important role in the material removal process. Lots of methods have been utilized to study this process, but a widely accepted explanation about this process has not been yet accomplished. In this study, the acoustic emission (AE) sensor was fixed on EDM machine to study the material removal process by observing the expansion and contraction process of gas bubble surrounding the discharge plasma. The machining performance in different working mediums was studied for Ti‐6Al‐4V machining in air, kerosene, and water‐based emulsion. Discharge in different working mediums would result in different material removal rates and surface quality. The difference of AE wave frequency domain distribution for discharge in different working mediums was studied. It was observed that the frequency of acoustic emission wave generated by discharge in different working mediums would be different. The characteristic difference of single AE wave generated by discharge in air, kerosene, and water‐based emulsion was compared. It was found that the duration time and peak amplitude of acoustic emission wave generated by discharge in different working mediums were different, and the acoustic emission wave generated by discharge in water‐based emulsion would last longer and get higher peak amplitude compared to discharge in air and kerosene. The significant difference of AE wave generated by discharge in water‐based emulsion from that in kerosene was found. Based on the acoustic emission wave observation, the special characteristic of the material removal process for discharge in water‐based emulsion was found.

Biodegradable Piezoelectric Transducer for Powering Transient Implants

Transient implantable medical devices based on biodegradable electronics can be used for diagnostic and therapeutic purposes for a desired duration and undergo biodegradation, unlike their conventional counterparts. However, powering transient implants through biodegradable power sources remains under-explored. Here, we report biodegradable piezoelectric transducer fabricated using 0-3 composite film made of barium titanate nanoparticles and poly (L-lactic-co-glycolic) acid polymer (BT-PLGA). The proposed BT-PLGA can be utilized in two different powering schemes; ultrasonic powering and energy harvesting from low frequency acoustic waves. We demonstrated that the power density of the BT-PLGA transducer can reach up to 10 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in ultrasonic powering. The energy harvesting from low frequency acoustic waves could also readily generate sufficient power for small electronics. The fabricated transducers underwent complete biodegradation in physiological conditions within 100 days. The development of the biodegradable piezoelectric transducer potentially provides a reliable power source for transient implants, especially for deeply seated bioelectronics. The output performance, biocompatibility, and tunable biodegradation of BT-PLGA transducer demonstrate its potential as a biodegradable power source for transient implantable devices.

Impact of the Langdon effect on crossed-beam energy transfer

The prediction that laser plasma heating distorts the electron distribution function away from Maxwellian and towards a super-Gaussian distribution dates back four decades1. In conditions relevant to inertial confinement fusion, however, no direct evidence of this so-called ‘Langdon effect’ has previously been observed. Here we present measurements of the spatially and temporally resolved Thomson scattering spectrum that indicate the presence of super-Gaussian electron distribution functions consistent with existing theory2. In such plasmas, ion acoustic wave frequencies increase monotonically with the super-Gaussian exponent3. Our results show that the measured power transfer between crossed laser beams mediated by ion acoustic waves requires a model that accounts for the non-Maxwellian electron distribution function, whereas the standard Maxwellian calculations overpredict power transfer over a wide region of parameter space. Including this effect is expected to improve the predictive capability of crossed-beam energy transfer modelling at the National Ignition Facility in California and may restore a larger operable design space for inertial confinement fusion experiments. This is also expected to motivate further inquiry in other areas affected by non-Maxwellian electron distribution functions, such as laser absorption, heat transport and X-ray spectroscopy. In inertial confinement fusion experiments, the effect of the overlapping laser beams on the plasma is predicted to lead to a distortion of the electron distribution function, which has now been observed in experiments.

Directional transmission of ultra-high frequency acoustic signals based on metamaterial structure

Cell photoacoustic detection of acoustic signals has serious problems of transmission loss and difficulty in acquisition. Based on the acoustic transmission characteristics of acoustic supermaterials, the acoustic wave directional transmission model is designed using COMSOL software, and a finite element simulation experiment was carried out. Experiments show that the model designed in this paper has good sound wave focusing and acoustic wave directional transmission effects. According to the specific application in different environments, this paper designs a variety of transmission models with different structures and carries out comparative experiments to verify the influence of complex model structures on the directional transmission of sound waves. At the same time, the experimental analysis of the acoustic wave directional transmission effect of the model under different frequency segments is carried out, and the possibility of acoustic wave logic operation is verified. Models can be applied to high frequency acoustic signal acquisition and sound wave transmission in complex environments. These studies have important significance for the development of cell photoacoustic detection technology and the application of metamaterial structures and have good practical merit.

A mechanical wave switch with tunable frequency output

Various acoustic and mechanical wave components have been developed. Most of them focused on the control of energy flow. However, these waves are not only energy flow but also wave signals with a frequency dependence. In this Letter, we propose a mechanical wave switch (MWS) capable of controlling energy flow and output frequency simultaneously. It consists of a difference frequency generation (DFG) unit and a wave filter. The DFG unit consists of two mass blocks and a tension/compression asymmetrical bilinear spring, and the wave filter is a one-dimensional mass-spring lattice. Systematical calculations were carried out to identify the critical condition for the design of MWSs. Both numerical and experimental results demonstrate the capability of the proposed MWS to tune the energy flow and the output frequency of acoustic waves via a small amplitude control wave signal. The scale-independent MWS can be implemented at micro- and nanoscales.

Experimental validation of time-reversal technique for defect detection in air-filled pipes using high frequency acoustic waves

Pipeline systems are extensively used for the transportation and distribution of the gas, water and petroleum products. The sustainability of the pipelines can be improved by utilizing the transient (acoustic)-based defect detection methods (TBDDM). In these methods, the probing pressure wave is generated in the pipe system, and the measured response is used to identify the defects. In this paper, experiments are performed on the acrylic pipe to study the acoustic wave propagation. The acrylic pipe is filled with air such that rigid pipe assumption is valid. Theoretical predictions applied with time reversal and match-field processing are validated with the experiments for the leak detection in a pipe system. The waveforms of Gaussian-modulated sine wave and Chirp are utilized as the transmitted signals in the frequency range of 1–15 kHz. The experimental results show that time-reversal technique is capable of accurate detection with a good resolution.

Time-reversal techniques for defect detection in pipe system using high frequency acoustic waves

Recent research has shown that transient (acoustic)-based defect detection methods (TBDDM) in water pipelines are a promising new approach that may help achieve more sustainable urban water supply systems (UWSS). These methods are based on the generation of a probing pressure wave in the pipe system, and the use of the measured response to identify defects. This paper develops an analytical solution for sound propagation in inviscid axisymmetric pipe system with sound source at the boundary. The solution is given for rigid and elastic pipe wall. This analytical model is used to apply time reversal and match-field processing to the detection of blockages and leaks in a single pipe system. The wave forms used at the source are Gaussian-modulated sine wave and Chirp with frequency ranging from 5 to 60 kHz. The results show accurate detection with resolution of the order of the probing wave length.

РАЗРАБОТКА МЕТОДИКИ РАСЧЁТА ЧАСТОТ АКУСТИЧЕСКИХ СТОЯЧИХ ВОЛН, ГЕНЕРИРУЕМЫХ РЕАКТОРАМИ ВВЭР

РАЗРАБОТКА МЕТОДИКИ РАСЧЁТА ЧАСТОТ АКУСТИЧЕСКИХ СТОЯЧИХ ВОЛН, ГЕНЕРИРУЕМЫХ РЕАКТОРАМИ ВВЭР

Asymmetric propagation of low-frequency acoustic waves in a granular chain using asymmetric intruders

This paper investigates the asymmetric propagation of acoustic waves in a one-dimensional chain of spherical particles coupled with asymmetric intruders. The chain passes acoustic waves along one direction (forward configuration) whereas partially blocks the acoustic energy propagating along the opposite direction (reverse configuration). A numerical analysis is conducted to investigate this asymmetric propagation by simulating a statically compressed chain of particles interacting via Hertzian contact and subjected to small amplitude periodic displacements at one end. The amount of acoustic energy transmitted through the chain in both configurations is studied and quantified in terms of the acoustic energy transfer ratio, defined as the ratio of the acoustic power at the last particle to the acoustic power at the first particle. The effect of the applied frequency and number of particles in the chain on the transfer ratio is investigated. In addition, a parametric study is performed to evaluate the effects of geometric and material properties on the efficiency of asymmetric acoustic wave propagation in the proposed system. The results show that the proposed design supports asymmetric propagation of low frequency acoustic waves.

Programmable multi-DNA release from multilayered polyelectrolytes using gigahertz nano-electromechanical resonator

BackgroundControllable and multiple DNA release is critical in modern gene-based therapies. Current approaches require complex assistant molecules for combined release. To overcome the restrictions on the materials and environment, a novel and versatile DNA release method using a nano-electromechanical (NEMS) hypersonic resonator of gigahertz (GHz) frequency is developed.ResultsThe micro-vortexes excited by ultra-high frequency acoustic wave can generate tunable shear stress at solid–liquid interface, thereby disrupting molecular interactions in immobilized multilayered polyelectrolyte thin films and releasing embedded DNA strands in a controlled fashion. Both finite element model analysis and experiment results verify the feasibility of this method. The release rate and released amount are confirmed to be well tuned. Owing to the different forces generated at different depth of the films, release of two types of DNA molecules with different velocities is achieved, which further explores its application in combined gene therapy.ConclusionsOur research confirmed that this novel platform based on a nano-electromechanical hypersonic resonator works well for controllable single and multi-DNA release. In addition, the unique features of this resonator such as miniaturization and batch manufacturing open its possibility to be developed into a high-throughput, implantable and site targeting DNA release and delivery system.

Acoustic focusing effect based on artificial periodic structure

To achieve high-efficiency acoustic focusing, an artificial periodic acoustic structure composed of two-dimensional three-component cell arrays was used to manipulate the transmission wave fronts of acoustic waves, and the acoustic field characteristics were numerically simulated by COMSOL finite element software. The results showed that whether the spherical acoustic wave generated by the point excitation source or the planar acoustic wave generated by the linear excitation source was used as the incident wave, an emission focus point can be generated at the top of the acoustic model. The intensity of the acoustic pressure at the focus point depended on the frequency of the incident acoustic waves. Under the same vibration period, the acoustic pressure will increase first and then decrease. It will reach a maximum value at the resonance frequency. In addition, when the model was cut into a right-angled trapezoidal structure with the axis of symmetry as a cross-section, the acoustic wave can produce a variable-direction focusing effect, and the “acoustic levitation” effect can also be realized. This series of anomalous acoustic phenomena can provide a new direction for acoustic directional transmission, acoustic wave detection, and acoustic stealth.

Influence of Confined Acoustic Phonons on the Nonlinear Acousto-electric Effect in Doped Semiconductor Superlattices

Abstract: By using a quantum kinetic equation for electrons, we have studied the Acousto-electric effects in doped semiconductor superlattice (DSSL) under the influence of confined phonon. Considering the case of the electron - acoustic phonon interaction, we have found the expressions of the nonlinear quantum acousto-electric current. From these expression, the acousto-electric current (AEC) depends nonlinearly on temperature, acoustic wave frequency and the characteristic parameters of DSSL (For example: the doped concentration ). Moreover, the expression of the AEC under the influence of confined phonons fairly different from the case of unconfined phonons.&#x0D; The results are numerically calculated for the GaAs:Be/ GaAs:Si DSSL; therefore, it can be easily seen that the dependence of the acousto-electric current on the characteristic parameters of the acoustic wave, temperature, the characteristic parameters of DSSL and the quantum number m characterizing the phonons confinement. The results have showed that the appearance of phonons confinement make the AEC value changes remarkably. The AEC is almost stable in low acoustic wave frequency condition and changes as a parabolic curve when move up. On the other hand, in case of low doped concentration number the AEC surges as a parabolic function in the dependence on , then it remains stability at just below zero in high value.&#x0D; Keywords: Acousto-electric field, Quantum kinetic equation, Doped superlattices, Electron - phonon interaction.&#x0D;

Quantitative analysis of low frequency acoustic characteristics for reverse horn by bottleneck effect analogy method

Reverse horn as one of the Acoustic Black Hole (ABH) structures can be used to effectively reduce low frequency acoustic waves by focusing the sound energy. The sound waves in relatively low frequency range are focused on the tip of reverse horn, and most sound energy cannot flow out from the reverse horn’s tip. In this paper, we propose a quantitative analysis method by the bottleneck effect analogy to research the low frequency acoustic characteristics of reverse horn. Our theoretical results show that the low frequency sound wave can be focused on the tip of reverse horn, and the transmission coefficient of low frequency is proportional to the 3 power law of the reverse horn tip’s diameter. The experimental results verified our theoretical results. And the sound insulation property is studied by experiments. It is noteworthy that the insulation coefficient of two levels reverse horn whose second level tip’s diameter [Formula: see text] mm, is more than 0.92, and can increase further with the decrease of the second level horn tip’s diameter. It provides an effective and simple method for quantitatively analyzing the low frequency acoustic characteristics of the reverse horn. The proposed reverse horn has great potential applications for low frequency sound insulation control.

Interaction phenomena of ion acoustic solitary waves with singly charged cold ions and Boltzmann electrons

The linear features and phenomena concerning head-on collision between the two ion acoustic solitary waves are investigated considering the multi-component plasma system comprising singly charged cold positive and negative ions, and Boltzmann electrons. Linear characteristics of ion acoustic solitary waves are studied taking the dispersion relation into account. The two-sided Korteweg-de Vries (KdV) equations are derived to investigate the structures of the solitons and the phase shift of ion acoustic solitary waves due to collisions by the extended Poincaré-Lighthill-Kuo (ePLK) method. The linear analyses reveal that the densities of the ionic species and wave number modify the ion acoustic solitary wave frequency, and higher density of electrons changes the group velocity. It is found that a new wave is produced with high amplitude in the interaction region due to head-on collision between the waves. The compressive and rarefactive KdV solitons are produced due to the changes of density. The density ratios such as and modify the phase shift and nonlinear phase velocity after head-on collision.

Simulation and inversion of harmonic infrasound from open-vent volcanoes using an efficient quasi-1D crater model

Volcanic activity excites low frequency acoustic waves, termed infrasound, in the atmosphere. Infrasound observations can be used to provide constraints on eruption properties, such as crater geometry and volume flux. At open-vent volcanoes, such as Erebus (Antarctica) and Villarrica (Chile), the infrasound signal is modulated by the crater properties. Eruptive activity at the bottom of the crater, such as unsteady degassing or explosions, can excite the air mass within the crater into resonance leading to infrasound generation with signals possessing clear spectral peaks, termed harmonics. Therefore, the effect of the crater on the infrasound signal, or crater acoustic response, must be accounted for when inverting harmonic infrasound observations for eruption properties at open-vent volcanoes. Here we develop a linearized model of quasi-one-dimensional (1D) wave propagation inside volcanic crater coupled with 3D axisymmetric radiation into the atmosphere from the crater, with waves generated by a volumetric flow rate source at the bottom of the crater. We perform simulations for a range of volcanic crater geometries, temperature profiles, gas compositions, and source descriptions to explore the influence of these properties on the infrasound signal. The observed infrasound signal depends on the flow rate source-time function, but interference of up- and down-going waves within the crater selectively amplifies the signal at the resonant frequencies of the crater. The crater resonance model presented here is verified by comparison with an established three-dimensional (3D) infrasound code and is shown to be appropriate for realistic crater geometries when the crater radius is less than approximately one quarter of the acoustic wavelength. The model presented here is more computationally efficient and can be used to invert infrasound observations for a range of properties, such as crater geometry or volumetric flow rate associated with eruptions. We demonstrate the utility of our efficient modeling framework by inverting harmonic infrasound observations for the crater geometry and position of the lava lake at Villarrica volcano. This technique may be used at other open-vent volcanoes to constrain dynamic crater geometry and provide insights about lava lake motions and infrasound producing eruption sources.

Theory of tuning ‘tunnelling-probability’ through potential barrier by acoustically augmented phonons (AAP)

This paper attempts to theoretically establish the technical possibility of manually controlling the tunnelling probability of phonons through potential barrier by superimposing Ultra High Frequency (UHF) acoustic wave over the source of phonons transmission, which results into Acoustically Augmented Phonons (AAP). Tuneable high fidelity acoustic piezoelectric transducer emitters may be used to tune the tunnelling. If the probability of reflectivity of phonon (P) during tunnelling through the potential barrier is given by P(R)p and that of Acoustically Augmented Phonons(AAP) is P(R)AAP then it is analytically obtained that P(R)AAP = ∝ P(R)P. Where ∝ is dimensionless number and is defined as the augmentation factor which is dependent on structure based damping coefficient, wave number of superimposed UHF acoustic wave and phonon’s kinetic energy. Enhancement of tunnelling probability by mechanically superimposing UHF acoustic wave over the in situ phonons is independent of initial UHF acoustic wave’s amplitude. It is noted that the range of ‘tunnelling enhancement AAP’s wave numbers’ (or frequencies) gradually broadens with increase in the kinetic energy of phonons and also gradually tends to a limit. Thus, existence of almost zero reflectivity of tunnelling probability through the potential barrier by Acoustically Augmented Phonons (AAP) is theoretically obtained. A general observation is that to achieve very low reflectivity of phonon tunnelling probability ‘structural damping factor’ must be small enough than superimposed UHF of acoustic wave number.

Numerical Simulation of Propagation Process of Acoustic Emission Partial Discharge Signal in Medium Voltage Switch-Gears

The rapid and accurate detection of partial discharges (PD) ensures the safe operation of the power grid. It is important to improve the reliability of power supply. When a partial discharge (PD) occurs, acoustic wave will be produced. Usually the partial discharge (PD) produces an acoustic wave frequency of about a few kHz in the gas. This article will use the acoustic simulation module in the Comsol Multiphysics software to simulate the propagation of ultrasonic waves inside and outside the switchgear. Since the transmission of ultrasonic waves is affected by many factors, the geometry of the switchgear is the main factor affecting the propagation of ultrasonic waves. Therefore, this paper will simulate the transmission process of ultrasonic waves under different conditions. Exploring the impact of different monitoring locations on monitoring results through simulation. Through the analysis of the simulation results of the ultrasonic propagation process, we got the following conclusions. As the thickness of the switchgear cabinet increases, it only affects the amplitude of the signal. Opening a hole in the cabinet of the switchgear makes it easier to detect ultrasonic signals outside the cabinet. As the number of openings in the cabinet of the switch cabinet increases, the amplitude of the signal monitored outside the cabinet increases. Four monitoring points are placed on the front, back, upper and lower sides of the switchgear cabinet. Through the simulation of the ultrasonic transmission process, it can optimize ultrasonic testing method and provide guidance for the detection method of ultrasonic waves in production activities.

Experimental investigation of entropy waves generated from acoustically excited premixed swirling flame

Entropy waves play an important role in the production of indirect combustion noise and thermoacoustic instability. The characteristics of entropy waves from swirling flames have not been systematically investigated. Here, a premixed methane/air swirl burner was built with upstream acoustic excitation from a loudspeaker. A joint infrared imaging and tunable diode laser absorption spectroscopy (TDLAS) thermometry measurement was carried out to investigate the entropy waves generated in this burner. The infrared imaging technique provides qualitative images of the distribution, propagation and dissipation of entropy waves while the TDLAS technique provides quantitative measurement of temperature fluctuation. Time resolved measurements of the swirling flame bulk velocity, CH* chemiluminescence, gas temperature and infrared images were simultaneously obtained, demonstrating that entropy waves were generated from the premixed swirling flame under external acoustic excitation. Entropy waves were shown to be greatly influenced by the amplitude and frequency of acoustic waves. They also showed dissipation as the entropy waves propagate downstream according to the attenuated temperature fluctuation and infrared radiation intensities. Simultaneous high speed infrared imaging and particle image velocimetry measurements showed that the temperature non-uniformities arise from engulfment and mixing through periodic vortex roll-up.

Ultra high frequency acoustic wave propagation in fully polymer based surface acoustic wave device

Surface acoustic wave (SAW) device, which integrates the generation, propagation and detection of acoustic waves into the same device, has been known to be an essential functional unit for sensors and electromechanical systems. However, high substrate cost and process complexity of traditional inorganic SAW devices have triggered extensive research efforts to seek for alternative low cost solution, especially for disposable application. Poly(vinylidenefluoride)[P(VDF)] and its co-polymer, despite being promising materials for acoustic transducer with inexpensive processing technique, have rarely been used in SAW device due to exhibiting extremely low operating frequency (few tens of MHz) compared to the traditional SAW device (few hundreds of MHz to GHz) based on inorganic piezoelectric material. Here we demonstrate SAW device, which is entirely based on Poly(vinylidenefluoride-trifluoroethylene) [P(VDF-TrFE)], as piezoelectric material, offering transduction and propagation of acoustic waves with a frequency around 450 MHz. The drawbacks of the previous attempts by the others are addressed and rectified systematically to obtain high operating frequency comparable to the traditional SAW. The influence of periodicity of interdigitated transducer and thickness of polymer film on device performance is thoroughly investigated. Temperature dependent variation of resonance frequency, which can be exploited as temperature sensor in integrated systems, is also demonstrated.