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Wyszukujesz frazę "acoustic field" wg kryterium: Temat

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    Wyświetlanie 1-12 z 12
    Tytuł:
    Modeling and Designing Acoustical Conditions of the Interior – Case Study
    Autorzy:
    Kostek, B.
    Laskowski, S.
    Mizgier, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/176652.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    acoustic field analysis
    acoustic field modeling
    acoustic conditions measurements
    acoustic conditions analysis
    sound reinforcement system design
    Opis:
    The primary aim of this research study was to model acoustic conditions of the Courtyard of the Gdańsk University of Technology Main Building, and then to design a sound reinforcement system for this interior. First, results of measurements of the parameters of the acoustic field are presented. Then, the comparison between measured and predicted values using the ODEON program is shown. Collected data indicate a long reverberation time which results in poor speech intelligibility. Then, a thorough analysis is perform to improve the acoustic properties of the model of the interior investigated. On the basis of the improved acoustic model two options of a sound reinforcement system for this interior are proposed, and then analyzed. After applying sound absorbing material it was noted that the predicted speech intelligibility increased from bad/poor rating to good category.
    Źródło:
    Archives of Acoustics; 2016, 41, 3; 473-484
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Deagglomeration and Coagulation of Particles in Liquid Metal Under Ultrasonic Treatment
    Autorzy:
    Kudryashova, Olga
    Vorozhtsov, Alexander
    Danilov, Pavel
    Powiązania:
    https://bibliotekanauki.pl/articles/176746.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    acoustic field
    ultrasonic processing
    metal melt
    nanoparticles
    acoustic coagulation
    cavitation
    acoustic deagglomeration
    Opis:
    Ultrasonic processing in the cavitation mode is used to produce the composite materials based on the metal matrix and reinforcing particles of micro- and nano-sizes. In such a case, the deagglomeration of aggregates and the uniform distribution of particles are the expected effects. Although the particles can not only fragment in the acoustic field, they also can coagulate, coarsen and precipitate. In this paper, a theoretical study of processes of deagglomeration and coagulation of particles in the liquid metal under ultrasonic treatment is made. The influence of various parameters of ultrasound and dispersion medium on the dynamics of particles in the acoustic field is considered on the basis of the proposed mathematical model. The criterion of leading process (coagulation or deagglomeration) has been proposed. The calculated results are compared with the experimental ones known from the scientific literature.
    Źródło:
    Archives of Acoustics; 2019, 44, 3; 543-549
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Acoustic Field Distribution Inside the Ultrasonic Ring Array
    Autorzy:
    Staszewski, W.
    Gudra, T.
    Opieliński, K. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/177105.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrasound transmission tomography
    acoustic field
    ultrasonic multi-element array
    Opis:
    This paper presents and analyses the results of a simulation of the acoustic field distribution in sectors of a 1024-element ring array, intended for the diagnosis of female breast tissue with the use of ultrasonic tomography. The array was tested for the possibility to equip an ultrasonic tomograph with an additional modality - conventional ultrasonic imaging with the use of individual fragments (sections) of the ring array. To determine the acoustic field for sectors of the ring array with a varying number of activated ultrasonic transducers, a combined sum of all acoustic fields created by each elementary transducer was calculated. By the use of MATLAB software, a unique algorithm was developed, for a numerical determination of the distribution of pressure of an ultrasonic wave on any surface or area of the medium generated by the concave curvilinear structure of rectangular ultrasound transducers with a geometric focus of the beam. The analysis of the obtained results of the acoustic field distribution inside the ultrasonic ring array used in tomography allows to conclude that the optimal number of transducers in a sector enabling to obtain ultrasound images using linear echographic scanning is 32 ≤ n ≤ 128, taking into account that due to an increased temporal resolution of ultrasonic imaging, this number should be as low as possible.
    Źródło:
    Archives of Acoustics; 2018, 43, 3; 455-463
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Effect of Dynamic Beam Deflection and Focus Shift on the Acoustic Field Distribution Inside the Ultrasonic Ring Array
    Autorzy:
    Staszewski, Wiktor
    Gudra, Tadeusz
    Opieliński, Krzysztof J.
    Powiązania:
    https://bibliotekanauki.pl/articles/176553.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    ultrasonic ring array
    acoustic field distribution
    ultrasonic beam focusing
    ultrasound tomography
    Opis:
    This paper presents the results of acoustic field distribution simulations for the 1024-element ultrasonic ring array intended for the diagnosis of female breast tissue with the use of ultrasound tomography. For the purpose of analysing data, all acoustic fields created by each elementary transducer were combined. The natural position of the focus inside the ultrasonic ring array was changed by altering activation time of individual transducers in sectors consisting of 32, 64, and 128 ultrasonic transducers. Manipulating the position of the focus inside the array will allow to concentrate the ultrasonic beam in a chosen location in the interior space of the ring array. The goal of this research is to receive the best possible quality of images of cross-sections of the female breast. The study also analysed the influence of the acoustic field distribution on the inclination of the beam. The results will enable to choose an optimal focus and an optimal number of activated transducers.
    Źródło:
    Archives of Acoustics; 2019, 44, 4; 625-636
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Use of Acoustic Vectors Decomposition of Sound Fields to Vibroacoustic Protection on Ships
    Autorzy:
    Weyna, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/177564.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    acoustic vectors field
    sound intensity
    ship acoustics
    Opis:
    In this paper, numerous examples will be illustrated as principles of applying the sound intensity measurements to practical problems at the noise abatement on ships and offshore constructions. The paper presents the results of transmission loss measurements together with flanking transmission for ship bulkheads and partitions with doors and windows. Investigations carried out with sound intensity measurement techniques will be compared against those made by classical methods. Finally for a few examples, the graphic presentation of spatial distribution of sound intensity vectors risen close to vibrating ship cabin partitions and inside the cabin will be shown in 2D and 3D graphical form. As a result, a two-dimensional acoustic wave flow map of time-averaged active intensity vectors propagated along curved streamlines and a vector perpendicular to measured plane are graphically illustrated. The technique of acoustic vectors decomposition of sound fields described, can enrich the knowledge of the mechanism of acoustic energy flux through ship partitions.
    Źródło:
    Archives of Acoustics; 2017, 42, 2; 207-212
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Testing the Acoustic Silencers
    Autorzy:
    Pierchała, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/176514.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    silencers
    aerodynamic noise
    noise reduction
    ventilation systems
    numerical tests
    acoustic field
    sound absorbing cassettes
    dispersing component
    Opis:
    Problems associated with designing silencers are presented. Results of direct tests of silencers for cooperation with systems of axial fans, as well as results of numerical tests of a two stage acoustic silencer, are given. The numerical tests enabled determining the distribution of acoustic field inside the silencer and in the surrounding area. In those tests A sound insertion losses for different variants of installation inside the silencer, as well as for two different types of absorbing material used to fill the silencer walls, were determined. Impact of design features of silencers on effectiveness of noise reduction is described. Also, a technical sketch of a universal silencer with significant noise reduction (DipS = 39:1 dB) which can be successfully used in many ventilation systems is presented.
    Źródło:
    Archives of Acoustics; 2018, 43, 2; 313-321
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estimation of Acoustic Impedance for Surfaces Delimiting the Volume of an Enclosed Space
    Autorzy:
    Piechowicz, J.
    Czajka, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/177215.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    acoustic impedance
    acoustic measurements
    numerical methods
    sound field
    Opis:
    Several methods can be applied for analyses of the acoustic field in enclosed rooms namely: wave propagation, geometrical or statistical analysis. The paper presents problems related to application of the boundary elements method to modelling of acoustic field parameters. Experimental and numerical studies have been combined for evaluation of acoustic impedance of the material used for the walls of a model room. The experimental studies have been carried out by implementing a multichannel measuring system inside the constructed model of an industrial room. The measuring system allowed simultaneous measurements of the source parameters – the loudspeaker membrane vibration speed, the acoustic pressure values in reception points located inside the model space as well as phase shifts between signals registered in various reception points. The numerical modelling making use of the acoustic pressure values measured inside the analyzed space allowed determination of requested parameters of the surface at the space boundary.
    Źródło:
    Archives of Acoustics; 2012, 37, 1; 97-102
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Design of Acoustic Tubes Array and Application to Measuring Acoustic Loads in Supersonic Airflow
    Autorzy:
    Wei, L.
    Li, M.
    Fu, Q.
    Fan, Y.
    Yang, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/176750.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    acoustic load
    acoustic tubes array
    near field measurement
    supersonic airflow
    Opis:
    In the acoustic fatigue experiment for hypersonic vehicle in simulated harsh service environment on ground, acoustic loads on the surface of test pieces of the vehicle need to be measured. However, for the normal microphones without high temperature resistance ability, the near field sound measurement cannot be achieved. In this work, on the basis of previous researches, an acoustic tubes array is designed to achieve the near field measurement of acoustic loads on the surface of the test piece in the supersonic airflow with high temperature achieved by coherent jet oxygen lance. Firstly, the process of designing this acoustic tubes array is introduced. Secondly, the equality of phase differences at the front and at the end of the tubes is stated and proved using a phase differences test with an acoustic tubes array whose design is presented in this text; therefore, the phase differences of signals acquired by microphones can be directly applied to beamforming algorithm to determine the acoustic load source. Finally, using above mentioned acoustic tubes array, measurement of acoustic load, with and without a test piece in the supersonic airflow made by the coherent jet oxygen lance, is conducted respectively, and the measurements results are analyzed.
    Źródło:
    Archives of Acoustics; 2014, 39, 3; 395-402
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sound Radiation of a Pulsating Sphere in the Outlet of a Hard/Soft Semi-Spherical Cavity in a Flat Screen
    Autorzy:
    Rdzanek, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/950213.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Neumann/Dirichlet problem
    sound field
    acoustic impedance
    continuity
    Opis:
    A rigorous analysis of sound radiation by a pulsating sphere forming a resonator together with a semispherical cavity is presented. Both hard and soft boundaries are considered, as well as mixed. The problem is solved by dividing the entire region into two subregions, one surrounding the sphere and containing the cavity and the other for the remaining half-space. The continuity conditions are applied to obtain the acoustic pressure. Then the acoustic radiation resistance is calculated both in the near- and far-field. The acoustic radiation reactance is calculated in the impedance approach. The resonance frequencies are determined, for which a significant growth of the sound pressure level is observed as well as the sound field directivity. The accuracy and convergence of these rigorous results has been examined empirically.
    Źródło:
    Archives of Acoustics; 2016, 41, 1; 75-86
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Active Transient Sound Radiation Control from a Smart Piezocomposite Hollow Cylinder
    Autorzy:
    Hasheminejad, S. M.
    Rabbani, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/177572.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    active structural acoustic control (ASAC) thick cylindrical shells
    exact elasto-acoustic analysis
    time-domain solution
    intelligent system
    sound field attenuation
    Opis:
    The linear 3D piezoelasticity theory along with active damping control (ADC) strategy are applied for non-stationary vibroacoustic response suppression of a doubly fluid-loaded functionally graded piezolaminated (FGPM) composite hollow cylinder of infinite length under general time-varying excitations. The control gain parameters are identified and tuned using Genetic Algorithm (GA) with a multi-objective performance index that constrains the key elasto-acoustic system parameters and control voltage. The uncontrolled and controlled time response histories due to a pair of equal and opposite impulsive external point loads are calculated by means of Durbin’s numerical inverse Laplace transform algorithm. Numerical simulations demonstrate the superior (good) performance of the GA-optimized distributed active damping control system in effective attenuation of sound pressure transients radiated into the internal (external) acoustic space for two basic control configurations. Also, some interesting features of the transient fluid-structure interaction control problem are illustrated via proper 2D time domain images and animations of the 3D sound field. Limiting cases are considered and accuracy of the formulation is established with the aid of a commercial finite element package as well as comparisons with the current literature.
    Źródło:
    Archives of Acoustics; 2015, 40, 3; 359-381
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Calculation for Acoustic Radiation Force from Rectangular Weakly Focusing Transducer Using the Ray Acoustic Model
    Autorzy:
    Yu, Lili
    Qiao, Shuchang
    Shou, Wende
    Li, Junhua
    Powiązania:
    https://bibliotekanauki.pl/articles/2141691.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    radiation force calculation
    ray acoustic model
    rectangular weakly focusing transducer
    far-field integration
    Opis:
    Based on the ray acoustic model, a new relationship between the radiation force and the acoustic power is studied for a rectangular weakly focusing transducer. The effect of pressure reflection coefficient on this model is discussed. For a totally absorbing target, an approximate closed-form expression is also derived and the performance of this model is compared with that of the far-field integration model. The numerical results show that the agreement is excellent with these two models, which can be both used for correction of measured results, but the formula based on the ray acoustic model can be applied more widely in practice because of its simpler expression. The experimental results show further the effectiveness of the relationship between radiation force and acoustic power for rectangular weakly focusing transducer based on the ray acoustic model. The results presented in this paper are important for application of ultrasound transducers in therapy.
    Źródło:
    Archives of Acoustics; 2022, 47, 1; 81-88
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sound Field Modelling and Noise Reduction for a Forklift Power Compartment Based on Perfectly Matched Layer and Acoustic Packaging Design
    Autorzy:
    Zhang, Enlai
    Liu, Zhiqi
    Zhang, Jingjing
    Lin, Jiahe
    Powiązania:
    https://bibliotekanauki.pl/articles/1945640.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    forklift power compartment
    sound field modelling
    perfectly matched layer
    acoustic packaging design
    noise reduction
    Opis:
    The core goal of this paper is to put forward a feasible scheme of noise reduction for a target forklift on the basis of solving the problem of vibration and acoustic radiation from complex structures in infinite domain. Based on the previous report and vibration acceleration tests, the acoustic virtual wind tunnel model of forklift power compartment was established using finite element method and boundary element method, in which the perfectly matched layer was first applied to simulate the attenuation propagation of sound waves in air. In addition, according to the distribution characteristics of sound pressure field with different frequencies, the acoustic energy mainly radiated through the bottom and right side, and concentrated in the low frequency. Consequently, the acoustic packaging design for the whole forklift power compartment was presented, and a satisfying noise reduction effect was achieved.
    Źródło:
    Archives of Acoustics; 2021, 46, 3; 491-498
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-12 z 12

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