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    Wyświetlanie 1-23 z 23
    Tytuł:
    Rotation motion of particles in sound field
    Autorzy:
    Didenkulov, I.
    Ezersky, A.
    Selivanovsky, D.
    Chernov, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/332816.pdf
    Data publikacji:
    2003
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    rotation motion
    sound field
    Opis:
    It is known that sound field produces longitudinal oscillation motion of medium. If there are floating particles in a medium those particles oscillate together with liquid. In this paper we consider dynamics of floating particles, which have rotational oscillations in acoustic field. This novel phenomena produces additional sound attenuation due to viscous damping. In the present paper this effect is analytically described. The expression for sound attenuation in suspensions of such particles and estimations of the value of the effect are obtained, and possible applications are discussed.
    Źródło:
    Hydroacoustics; 2003, 6; 167-170
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sentence Recognition in the Presence of Competing Speech Messages Presented in Audiometric Booths with Reverberation Times of 0.4 and 0.6 Seconds
    Autorzy:
    Abouchacra, K. S.
    Koehnke, J.
    Besing, J.
    Letowski, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/177482.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    sound field testing
    reverberation
    speech recognition
    Opis:
    This study examined whether differences in reverberation time (RT) between typical sound field test rooms used in audiology clinics have an effect on speech recognition in multi-talker environments. Separate groups of participants listened to target speech sentences presented simultaneously with 0-to-3 competing sentences through four spatially-separated loudspeakers in two sound field test rooms having RT = 0:6 sec (Site 1: N = 16) and RT = 0:4 sec (Site 2: N = 12). Speech recognition scores (SRSs) for the Synchronized Sentence Set (S3) test and subjective estimates of perceived task difficulty were recorded. Obtained results indicate that the change in room RT from 0.4 to 0.6 sec did not significantly influence SRSs in quiet or in the presence of one competing sentence. However, this small change in RT affected SRSs when 2 and 3 competing sentences were present, resulting in mean SRSs that were about 8–10% better in the room with RT = 0:4 sec. Perceived task difficulty ratings increased as the complexity of the task increased, with average ratings similar across test sites for each level of sentence competition. These results suggest that site-specific normative data must be collected for sound field rooms if clinicians would like to use two or more directional speech maskers during routine sound field testing.
    Źródło:
    Archives of Acoustics; 2011, 36, 1; 3-14
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A System for Acoustic Field Measurement Employing Cartesian Robot
    Autorzy:
    Szczodrak, M.
    Kurowski, A.
    Kotus, J.
    Czyżewski, A.
    Kostek, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/221435.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Cartesian robot
    sound intensity
    sound field
    anechoic chamber
    Opis:
    A system setup for measurements of acoustic field, together with the results of 3D visualisations of acoustic energy flow are presented in the paper. Spatial sampling of the field is performed by a Cartesian robot. Automatization of the measurement process is achieved with the use of a specialized control system. The method is based on measuring the sound pressure (scalar) and particle velocity(vector) quantities. The aim of the system is to collect data with a high precision and repeatability. The system is employed for measurements of acoustic energy flow in the proximity of an artificial head in an anechoic chamber. In the measurement setup an algorithm for generation of the probe movement path is included. The algorithm finds the optimum path of the robot movement, taking into account a given 3D object shape present in the measurement space. The results are presented for two cases, first without any obstacle and the other - with an artificial head in the sound field.
    Źródło:
    Metrology and Measurement Systems; 2016, 23, 3; 333-343
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    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:
    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:
    Traffic Noise Models for Curved Roads
    Autorzy:
    Popescu, D. I.
    Cosma, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/176976.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    traffic noise
    noise source modelling
    sound field
    curved road
    Opis:
    The paper presents two theoretical models for traffic noise level distribution on curved horizontal roads. In the case of vehicles moving on a given route, one can consider, in terms of sound field, that the granular traffic is equivalent for short periods with a quasi-continuous noise flow. When computing and modelling the noise level generated by traffic on roads with complex trajectory, it is common to treat the route as a sum of small length road segments, each being assimilated with a linear noise source. This paper started from the assumption that the route can be decomposed into a sequence of linear and arc-shaped road segments, each of which is treated as a linear respectively curved noise source. An arc-shaped road segment is modelled by a tubular vibrating surface, of circular or rectangular section. In the case of rectangular section, the vibrating blade emits complex sounds on its both vertical sides and the generated sound field can be described more clearly, qualitatively and quantitatively, through intensity distribution. The theoretical models presented in the paper have direct application to the traffic noise prediction and noise maps drawing.
    Źródło:
    Archives of Acoustics; 2016, 41, 2; 309-314
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Particle Image Velocimetry and Proper Orthogonal Decomposition Applied to Aerodynamic Sound Source Region Visualization in Organ Flue Pipe
    Autorzy:
    Mickiewicz, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/177661.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Aeroacoustics
    POD
    PIV
    organ flue pipe
    sound field
    visualization
    Opis:
    The paper presents experimental results of the visualization of the nonlinear aeroacoustic sound generation phenomena occurring in organ flue pipe. The phase-locked particle image velocimetry technique is applied to visualize the mixed velocity field in the transparent organ flue pipe model made from Plexiglas. Presented measurements were done using synchronization to the tone generated by the pipe itself supplied by controlled air flow with seeding particles. The time series of raw velocity field distribution images show nonlinear sound generation mechanisms: the large amplitude of deflection of the mean flue jet and vortex shedding in the region of pipe mouth. Proper Orthogonal Decomposition (POD) was then applied to the experimental data to separately visualize the mean mass flow, pulsating jet mass flow with vortices and also sound waves near the generation region as well as inside and outside of the pipe. The resulting POD spatial and temporal modes were used to approximate the acoustic velocity field behaviour at the pipe fundamental frequency. The temporal modes shapes are in a good agreement with the microphone pressure signal shape registered from a distance. Obtained decomposed spatial modes give interesting insight into sound generating region of the organ pipe and the transition area towards the pure acoustic field inside the resonance pipe. They can give qualitative and quantitative data to verify existing sound generation models used in Computational Fluid Dynamics (CFD) and Computational Aero-Acoustics (CAA).
    Źródło:
    Archives of Acoustics; 2015, 40, 4; 475-484
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Revised Sound Energy Theory Based on a New Formula for the Reverberation Radius in Rooms with Non-Diffuse Sound Field
    Autorzy:
    Arau-Puchades, H.
    Berardi, U.
    Powiązania:
    https://bibliotekanauki.pl/articles/177958.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    reverberation radius
    critical distance
    non-diffuse sound field
    sound energy
    revised sound decay theory
    Opis:
    This paper discusses the concept of the reverberation radius, also known as critical distance, in rooms with non-uniformly distributed sound absorption. The reverberation radius is the distance from a sound source at which the direct sound level equals the reflected sound level. The currently used formulas to calculate the reverberation radius have been derived by the classic theories of Sabine or Eyring. However, these theories are only valid in perfectly diffused sound fields; thus, only when the energy density is constant throughout a room. Nevertheless, the generally used formulas for the reverberation radius have been used in any circumstance. Starting from theories for determining the reverberation time in non-diffuse sound fields, this paper firstly proposes a new formula to calculate the reverberation radius in rooms with non-uniformly distributed sound absorption. Then, a comparison between the classic formulas and the new one is performed in some rectangular rooms with non-uniformly distributed sound absorption. Finally, this paper introduces a new interpretation of the reverberation radius in non-diffuse sound fields. According to this interpretation, the time corresponding to the sound to travel a reverberation radius should be assumed as the lower limit of integration of the diffuse sound energy.
    Źródło:
    Archives of Acoustics; 2015, 40, 1; 33-40
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Systematic error of acoustic particle image velocimetry and its correction
    Autorzy:
    Mickiewicz, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/221013.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    particle image velocimetry
    acoustic measurement
    acoustic particle velocity
    sound field analysis
    Opis:
    Particle Image Velocimetry is getting more and more often the method of choice not only for visualization of turbulent mass flows in fluid mechanics, but also in linear and non-linear acoustics for non-intrusive visualization of acoustic particle velocity. Particle Image Velocimetry with low sampling rate (about 15Hz) can be applied to visualize the acoustic field using the acquisition synchronized to the excitation signal. Such phase-locked PIV technique is described and used in experiments presented in the paper. The main goal of research was to propose a model of PIV systematic error due to non-zero time interval between acquisitions of two images of the examined sound field seeded with tracer particles, what affects the measurement of complex acoustic signals. Usefulness of the presented model is confirmed experimentally. The correction procedure, based on the proposed model, applied to measurement data increases the accuracy of acoustic particle velocity field visualization and creates new possibilities in observation of sound fields excited with multi-tonal or band-limited noise signals.
    Źródło:
    Metrology and Measurement Systems; 2014, 21, 3; 447-460
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Impact of Wall Impedance Phase Angle on Indoor Sound Field and Reverberation Parameters Derived from Room Impulse Response
    Autorzy:
    Meissner, Mirosław
    Zieliński, Tomasz
    Powiązania:
    https://bibliotekanauki.pl/articles/31340118.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    room acoustics
    complex wall impedance
    indoor sound field
    room impulse response
    reverberation parameters
    Opis:
    Accurate definition of boundary conditions is of crucial importance for room acoustic predictions because the wall impedance phase angle can affect the sound field in rooms and acoustic parameters applied to assess a room reverberation. In this paper, the issue was investigated theoretically using the convolution integral and a modal representation of the room impulse response for complex-valued boundary conditions. Theoretical considerations have been accompanied with numerical simulations carried out for a rectangular room. The case of zero phase angle, which is often assumed in room acoustic simulations, was taken as a reference, and differences in the sound pressure level and decay times were determined in relation to this case. Calculation results have shown that a slight deviation of the phase angle with respect to the phase equal to zero can cause a perceptual difference in the sound pressure level. This effect was found to be due to a change in modal frequencies as a result of an increase or decrease in the phase angle. Simulations have demonstrated that surface distributions of decay times are highly irregular, while a much greater range of the early decay time compared to the reverberation time range indicates that a decay curve is nonlinear. It was also found that a difference between the decay times predicted for the complex impedance and real impedance is especially clearly audible for the largest impedance phase angles because it corresponds approximately to 4 just noticeable differences for the reverberation metrics.
    Źródło:
    Archives of Acoustics; 2022, 47, 3; 343-353
    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
    Tytuł:
    Full-wave Analysis of Periodic Baffle System in Beamforming Applications
    Autorzy:
    Tasinkevych, Y.
    Danicki, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/177861.pdf
    Data publikacji:
    2010
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    sound field calculation
    linear phased arrays
    BIS expansion
    far-field radiation pattern
    beam-steering
    transducer arrays
    composite transducers
    scattering
    generation
    fields
    Opis:
    Mixed boundary-value problem for periodic baffles in acoustic medium is solved with help of the method developed earlier in electrostatics. The nice feature of the method is that the resulting matrices are relatively easy for computations and that the results satisfy exactly the energy conservation law. Illustrative numerical examples present the wave-beam steering (in the far-field) in a baffle system that may be considered as a model of one-dimensional ultrasonic transducer array.
    Źródło:
    Archives of Acoustics; 2010, 35, 4; 661-675
    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:
    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:
    Mapy dźwiękowe w Polsce
    Sound map of Poland
    Autorzy:
    Kozak, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/370504.pdf
    Data publikacji:
    2014
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    mapa dźwiękowa
    audiosfera
    field recording
    krajobraz dźwiękowy
    sound map
    audiosphere
    sound landscape/ soundscape
    Opis:
    Mapa dźwiękowa to rodzaj archiwum dźwięków nagranych w terenie. Publikowanie nagrań odbywa się najczęściej poprzez internet na specjalnie do tego przygotowanej platformie umożliwiającej odsłuchiwanie dźwięków i sytuacji fonicznych z wybranego miejsca. Niniejsza praca jest opisem i porównaniem istniejących i udostępnionych map polskich miast i próbą odpowiedzi na pytanie dotyczące możliwości jakie stwarza archiwizowanie nagrań dźwiękowych.
    A sound map is a kind of an archive of sounds recorded in the field. Making them public is done through the Internet, on a specially prepared platform which makes it possible to listen to the sounds and phonic situations from the selected place. This paper is a description and comparison of the existing and publicly available sound maps of Polish cities. It is also an attempt to answer the question about the possibilities created by having sound recordings archived.
    Źródło:
    Przestrzeń i Forma; 2014, 21; 323-338
    1895-3247
    2391-7725
    Pojawia się w:
    Przestrzeń i Forma
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Numerical Approach to Calculate the Radiation Efficiency of Baffled Planar Structures Using the Far Field
    Autorzy:
    González-Montenegro, M. A.
    Jordan, R.
    Lenzi, A.
    Arenas, J. P.
    Powiązania:
    https://bibliotekanauki.pl/articles/176303.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    propagating matrix
    far field
    sound power
    structural finite element analysis
    Opis:
    A numerical method is developed for estimating the acoustic power of any baffled planar structure, which is vibrating with arbitrary surface velocity profile. It is well known that this parameter may be calculated with good accuracy using near field data, in terms of an impedance matrix, which is generated by the discretization of the vibrating surface into a number of elementary radiators. Thus, the sound pressure field on the structure surface can be determined by a combination of the matrix and the volume velocity vector. Then, the sound power can be estimated through integration of the acoustic intensity over a closed surface. On the other hand, few works exist in which the calculation is done in the far field from near field data by the use of radiation matrices, possibly because the numerical integration becomes complicated and expensive due to large variations of directivity of the source. In this work a different approach is used, based in the so-called Propagating Matrix, which is useful for calculating the sound pressure of an arbitrary number of points into free space, and it can be employed to estimate the sound power by integrating over a finite number of pressure points over a hemispherical surface surrounding the vibrating structure. Through numerical analysis, the advantages/disadvantages of the current method are investigated, when compared with numerical methods based on near field data. A flexible rectangular baffled panel is considered, where the normal velocity profile is previously calculated using a commercial finite element software. However, the method can easily be extended to any arbitrary shape. Good results are obtained in the low frequency range showing high computational performance of the method. Moreover, strategies are proposed to improve the performance of the method in terms of both computational cost and speed.
    Źródło:
    Archives of Acoustics; 2014, 39, 2; 249-260
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Educational Implementation of a Sound Level Meter in the LabVIEW Environment
    Autorzy:
    Barański, R.
    Wszołek, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/177784.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    LabVIEW
    acoustics
    sound level meters
    microphones
    free-field investigation
    frequency responses
    Opis:
    As a consequence of recent implementations of EU Directives related to noise protection more and more students of various AGH-UST programs are introduced to the basics of acoustic measurements. Students at various levels of theoretical background in the field of acoustic measurements are offered practical training in measurements using digital sound analyzers. The situation would be optimal if each student could have a device at his/her own disposal. Unfortunately, such a situation is not possible at the moment because of various reasons. With the above problem in mind, a dedicated software package has been developed, implemented in the LabVIEW environment, which allows detailed studies of problems related to the acoustic signal measurement using sound level meters, as well as tasks in spectral analysis (1/1 and 1/3 band filters) and narrow-band (FFT) analysis. With such organization during the introductory laboratory classes each student is offered a direct individual contact with a virtual device that is properly pre-programmed for realization of a well-constructed learning process. It definitely facilitates understanding of the essence of acoustic signal measurements and provides a good basis for further laboratory work carried out as a team-activity.
    Źródło:
    Archives of Acoustics; 2013, 38, 1; 19-26
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    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:
    Ścieżki Chrisa Watsona. Afekty i performatywna sprawczość nagrań terenowych w kinie doby katastrofy ekologicznej
    Chris Watsons Tracks. Affects and Performative Agency of Field Recordings in the Cinema of Climate Disaster Era
    Autorzy:
    Michnik, Antoni
    Powiązania:
    https://bibliotekanauki.pl/articles/31340584.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Instytut Sztuki PAN
    Tematy:
    afekt
    nagrania terenowe
    Chris Watson
    design dźwiękowy
    dźwięk
    dokumenty przyrodnicze
    katastrofa klimatyczna
    affect
    field recording
    sound
    nature documentaries
    climate disaster
    sound design
    Opis:
    Autor przygląda się afektywnym aspektom oraz związanej z nimi performatywnej sprawczości wykorzystania we współczesnym kinie nagrań terenowych. Wywód jest zogniskowany wokół twórczości i postaci Chrisa Watsona, specjalisty od nagrań terenowych przyrody, pracującego m.in. dla BBC, zwłaszcza przy produkcjach Davida Attenborough. Zestawiając dyskursy współczesnych afektywnych teorii kina i jego warstwy dźwiękowej (m.in. Michela Chiona, Barbary Flückiger, Caryl Flinn, Danijeli Kulezic-Wilson) z dyskursami wokół samego field recordingu (Francisco López) oraz różnymi narzędziami współczesnej humanistyki, autor pokazuje, w jaki sposób nagrania terenowe współtworzą afektywne narracje filmów oraz oddziałują na odbiorcę, budując przestrzeń światów przedstawionych, a także w jaki sposób nagrania terenowe przyrody wpisują się w szerszy krajobraz afektywny niepokojów doby katastrofy klimatycznej.
    The author examines affective dimensions and performative agency of field recordings used in contemporary cinema. The narrative is centred around the works of Chris Watson, a specialist in the field of nature recordings, and a long-time collaborator of David Attenborough in his BBC productions. The essay juxtaposes contemporary affective theories of cinema and its soundtrack (i.a. Michel Chion, Barbara Flückiger, Caryl Flinn, Danijela Kulezic-Wilson) with discourses of field recording itself (Francisco López) and different tools of current humanities, to show how field recordings co-create cinema’s affective narrations, as well as affecting the viewer through the creation of the space of cinematic worlds. The author also analyses the functioning of field recordings within broader affective landscape of uncertainty in the age of climate disaster.
    Źródło:
    Kwartalnik Filmowy; 2020, 111; 105-122
    0452-9502
    2719-2725
    Pojawia się w:
    Kwartalnik Filmowy
    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:
    Active Transient Acousto-Structural Response Control of a Smart Cavity-Coupled Circular Plate System
    Autorzy:
    Hasheminejad, S. M.
    Shakeri, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/176771.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    sound radiation
    structural-borne noise control
    coupled multi-field problem
    piezoelectric disc actuator
    cylindrical enclosure
    GA-tuned controller
    Opis:
    The transient vibroacoustic response suppression of a piezo-coupled sandwich circular plate backed by a rigid-walled cylindrical acoustic enclosure is investigated. Problem formulation is based on the linear acoustic wave theory, Kirchhoff thin plate model, fluid/structure compatibility relations, Rayleigh integra formula, and active damping control (ADC) strategy. Matlab’s Genetic Algorithm (GA) is utilized to identify and optimize the feedback controller gain parameter based on a multi-objective performance index function. Durbin’s numerical Laplace inversion scheme is then used to calculate the key acousto-structural response parameters due to a transverse impulsive shock force for selected cavity depths. Numerical simulations demonstrate satisfactory performance of adopted control methodology in effective suppression of panel displacement response and radiated external sound pressure for enclosures of shallow and moderate depths. Limiting cases are considered and accuracy of the proposed model is rigorously verified.
    Źródło:
    Archives of Acoustics; 2017, 42, 2; 273-286
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sound transmission loss calculation for metamaterial plate using combined analytical and numerical approach
    Autorzy:
    Chojnacka, Klara
    Kras, Aleksander
    Kamisiński, Tadeusz
    Powiązania:
    https://bibliotekanauki.pl/articles/24201968.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    locally resonant structures
    metamaterials
    sound transmission loss
    simulations
    diffuse field
    struktury miejscowo rezonujące
    metamateriały
    strata transmisji dźwięku
    symulacje
    pola rozproszone
    Opis:
    In recent years acoustic metamaterials are broadly investigated in many different fields of acoustics and one of them is noise and vibration mitigation. The solution with highest potential are locally resonant metamaterials (LRS), which by creation of band gap effect in flexural wave propagation in structure improve its Sound Transmission Loss (STL). Standard STL simulation procedures can be fully analytical or numerical. Analytical solution, when it comes to metamaterial modelling, is fast but it does not take into consideration metamaterial geometry. On the other hand numerical solution even when considering small part of periodic structure, is time consuming and can generate numerical errors related for example to the mesh. In this work combined analytical - numerical method is analysed as the alternative for STL calculation. This method can be a substitute for basic simulation procedures concerning vibro-acoustic metamaterials, since the simulations results are comparable and it is less time consuming method. Formulas and simulation procedure for the presented method are described and compared with analytical and numerical simulation results as well as with STL measurement results.
    Źródło:
    Vibrations in Physical Systems; 2022, 33, 3; art. no. 2022314
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ocena wpływu modyfikacji kształtu krawędzi górnej ekranu akustycznego na rozkład pola akustycznego po stronie odbiorcy
    Evaluation of influence shape modification of sound barrier upper edge on the acoustic field distribution by receiver side
    Autorzy:
    Dulak, L
    Marchacz, M
    Nowoświat, A
    Olechowska, M
    Żuchowski, R
    Powiązania:
    https://bibliotekanauki.pl/articles/362988.pdf
    Data publikacji:
    2011
    Wydawca:
    Instytut Fizyki Budowli Katarzyna i Piotr Klemm
    Tematy:
    ekrany akustyczne
    kształt górnej krawędzi
    nakładka krawędziowa
    dyfrakcja
    rozkład pola akustycznego
    sound barriers
    upper edge shape
    edge cover
    diffraction
    acoustic field distribution
    Opis:
    Artykuł przedstawia badania modelowe w komorze bezechowej ekranu akustycznego w skali 1:1 wraz z nakładka krawędziową o pewnym kształcie. Uzyskane wyniki są podstawą do oceny jakościowej i ilościowej zastosowanego rozwiązania w kontekście zmiany pola akustycznego za ekranem po stronie odbiorcy w wyniku zastosowania nakładki krawędziowej.
    Article presents model investigations of sound barrier in non-echo chamber in 1:1 scale together with some shape edge cover. Achieved results are a base to qualitatively and quantitatively evaluation of used edge cover design account distribution of sound field behind sound barrier on the receiver side as a results of used edge cover.
    Źródło:
    Fizyka Budowli w Teorii i Praktyce; 2011, T. 6, nr 4, 4; 15-20
    1734-4891
    Pojawia się w:
    Fizyka Budowli w Teorii i Praktyce
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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