Temat: reflection, - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Efficiency of Ultrasonic Comb Transducers
Autorzy:: Danicki, E. J.
Powiązania:: https://bibliotekanauki.pl/articles/176949.pdf
Data publikacji:: 2011
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: ultrasonic transducers
interface waves
Bragg reflection
Opis:: Comb transducers are applied in ultrasonic testing for generation of Rayleigh or Lamb waves by scattering of the incident bulk waves onto surface waves at the periodic comb-substrate interface. Hence the transduction efficiency, although rarely discussed in literature, is an important factor for applications determining the quality of the measured ultrasonic signals. This paper presents the full-wave theory of comb transducers concluded by evaluation of their efficiency for a couple of examples of standard and certain novel configurations.
Źródło:: Archives of Acoustics; 2011, 36, 4; 887-900
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: The Characteristic of Sound Reflections from Curved Reflective Panels
Autorzy:: Szeląg, A.
Kamisiński, T.
Lewińska, M.
Rubacha, J.
Pilch, A.
Powiązania:: https://bibliotekanauki.pl/articles/177712.pdf
Data publikacji:: 2014
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: sound reflection
reflective panels
sound scattering
Opis:: The paper presents the verification of a solution to the narrow sound frequency range problem of flat reflective panels. The analytical, numerical and experimental studies concerned flat panels, panels with curved edges and also semicircular elements. There were compared the characteristics of sound reflected from the studied elements in order to verify which panel will provide effective sound reflection and also scattering in the required band of higher frequencies, i.e. above the upper limit frequency. Based on the conducted analyzes, it was found that among some presented solutions to narrow sound frequency range problem, the array composed of panels with curved edges is the most preferred one. Nevertheless, its reflection characteristic does not meet all of the requirements, therefore, it is necessary to search for another solution of canopy which is effective over a wide frequency range.
Źródło:: Archives of Acoustics; 2014, 39, 4; 549-558
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Sound Reflection from Overhead Stage Canopies Depending on Ceiling Modification
Autorzy:: Kamisiński, T.
Szeląg, A.
Rubacha, J.
Powiązania:: https://bibliotekanauki.pl/articles/178128.pdf
Data publikacji:: 2012
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: sound reflection
room acoustics
reflecting structures
Opis:: Reflecting structures placed over the stage in auditoria and concert halls should provide sound reflection in a way that enhances sound emission from the stage without causing acoustic defects in the interior. Model studies conducted by the authors were used to determine the relative level of sound reflection by reflecting structures as a function of frequency for a number of geometric configurations and materials. Analysis of the results allowed drawing conclusions about the effect of modifications of the ceiling over the reflecting panels on the quality of the sound reflected from them. It was shown that modification of the ceiling over the reflecting panels by employing highly sound absorbing materials significantly improved the characteristics of the reflected sound. Also, certain configurations of elements located in the space under the ceiling should be avoided, as the experiments indicated the occurrence of adverse acoustic effects.
Źródło:: Archives of Acoustics; 2012, 37, 2; 213-218
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Rayleigh Waves in an isotropic Body with Deep Periodic Grooves
Autorzy:: Danicki, E.
Powiązania:: https://bibliotekanauki.pl/articles/178010.pdf
Data publikacji:: 2010
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: surface acoustic waves
Bragg reflection
comb transducers
Opis:: Bragg scattering of waves propagating in a periodically disturbed substrate is widely applied in optics and micro-acoustic systems. Here, it is studied for Rayleigh waves propagating on a periodically grooved elastic substrate. Practically applied groove depth in the Bragg grating reflectors does not exceed a few percent of the Rayleigh wavelength. Here, the analysis is carried out for periodic grooves of larger depth by applying the elastic plate model for the groove walls. The computed results show that the surface wave existence and reflection depends strongly on both the groove depth and period, and that there are limited domains of both for practical applications, primarily in comb transducers of surface waves.
Źródło:: Archives of Acoustics; 2010, 35, 1; 67-74
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Real-Time Acoustic Phenomena Modelling for Computer Games Audio Engine
Autorzy:: Miga, B.
Ziółko, B.
Powiązania:: https://bibliotekanauki.pl/articles/177439.pdf
Data publikacji:: 2015
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: sound reflection
transmission
attenuation
real-time audio processing
Opis:: This article presents an efficient method of modelling acoustic phenomena for real-time applications such as computer games. Simplified models of reflections, transmission, and medium attenuation are described along with assessments conducted by a professional sound designer. The article introduces representation of sound phenomena using digital filters for further digital audio processing.
Źródło:: Archives of Acoustics; 2015, 40, 2; 205-211
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Application of the Ultrasonic Ring Array Used in UTT for the Reflection Method Examinations of Structures
Autorzy:: Staszewski, Wiktor
Gudra, Tadeusz
Opieliński, Krzysztof J.
Powiązania:: https://bibliotekanauki.pl/articles/1945647.pdf
Data publikacji:: 2021
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:: ultrasonic reflection tomography
dynamic focusing
ultrasonic ring array
Opis:: The ultrasonic ring array, designed for examining the female breast with the use of ultrasonic transmission tomography (UTT), has been adapted for reflection method trials. By altering the activation time of ultrasonic elementary transducers, the parameters of the focus were changed with the aim at improving the quality of the obtained ultrasound image. For this purpose, a phantom consisting of rods having varying thicknesses was analyzed when moving the position of the focus with the use of dynamic focusing along the symmetry axis of the ring array ranging from 30 to 130 mm from central transducers. In previous trials, which applied an algorithm using the sum of all the acoustic fields, a series of simulations was performed in conditions identical to the phantom trial. This paper documents attempts at improving the parameters of the acoustic field distribution during unconventional focusing. The research here presented is a continuation of examinations focusing on the acoustic field distribution inside the ultrasonic ring array with the aim at finding the best possible cross-section of the female breast using the reflection method.
Źródło:: Archives of Acoustics; 2021, 46, 3; 427-434
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: The Comprehensive Research of the Road Acoustic Screen with Absorbing and Diffusing Surface
Autorzy:: Kamisiński, T.
Kinasz, R.
Szeląg, A.
Rubacha, J.
Pilch, A.
Flach, A.
Baruch, K.
Powiązania:: https://bibliotekanauki.pl/articles/177952.pdf
Data publikacji:: 2015
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: acoustics
mechanical strength
environmental actions
sound reflection
sound diffusion
Opis:: The paper presents the new solution to a road acoustic screen consisting of elements which are highly diffusing and simultaneously resistant to weathering, but also characterised by a sound absorption. There is described the comprehensive research of such the road acoustic screen with absorbing and diffusing surface. The study includes screen’s resistance to wind load and snow removal, impact tests and measurements of some acoustic parameters.
Źródło:: Archives of Acoustics; 2015, 40, 1; 137-144
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Revisiting the Open-End Reflection Coefficient and Turbulent Losses in an Organ Pipe with Low Mach Number Flow
Autorzy:: Hruška, Viktor
Dlask, Pavel
Powiązania:: https://bibliotekanauki.pl/articles/1953497.pdf
Data publikacji:: 2021
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:: organ pipe
reflection coefficient
end correction
flow-acoustic interactions
Opis:: The reflection coefficient of the open end belongs among the essential parameters in the physical description of a flue organ pipe. It leads directly to practical topics such as the pipe scaling. In this article, sound propagation is investigated inside an organ pipe with the most intense mean flow that is achievable under musically relevant conditions. A theoretical model is tested against the experimental data to obtain a suitable formula for the reflection coefficient when a non-negligible flow through the open end is considered. The velocity profile is examined by means of particle image velocimetry. A fully developed turbulent profile is found and interactions of the acoustic boundary layer with the turbulent internal flow are discussed. A higher value of the end correction than expected from the classical result of Levine and Schwinger is found, but this feature shall be associated with the pipe wall thickness rather than the mean flow effects.
Źródło:: Archives of Acoustics; 2021, 46, 2; 197-204
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Formation of Scattering Characteristics for Acoustical Ray Tracing Simulation
Autorzy:: Bojičić, S.
Šumarac-Pavlović, D.
Mijić, M.
Powiązania:: https://bibliotekanauki.pl/articles/178159.pdf
Data publikacji:: 2018
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: diffuse reflection
ray tracing
room acoustics
secondary source
scattering pattern
Opis:: Ray tracing simulation of sound field in rooms is a common tool in room acoustic design for predicting impulse response. There are numerous commercial engineering tools utilising ray tracing simulation. A specific problem in the simulation is the modelling of diffuse reflections when contribution of individual surface is prevailing. The paper introduces modelling of scattering which is interesting when the whole impulse response of a room is not a goal but contribution of certain surface. The main goal of the Project is to shape directivity characteristics of scattered reflection. Also, an innovative approach is suggested for converting the energy histogram information obtained by ray tracing into an “equivalent impulse response”. The proposed algorithm is tested by comparing the results with measurements in a real sound field, realised in a scaled model where a diffusing surface is hardware-implemented.
Źródło:: Archives of Acoustics; 2018, 43, 4; 657-667
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Reflection and Transmission of Plane Wave at an Interface Between Two Rotating Micropolar Piezoelectric Solid Half-Spaces
Autorzy:: Singh, Baljeet
Sangwan, Asha
Singh, Jagdish
Powiązania:: https://bibliotekanauki.pl/articles/2141703.pdf
Data publikacji:: 2021
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: plane wave
micropolar piezoelectricity
reflection and transmission
amplitude ratios
energy ratios
rotation
Opis:: In this paper, we investigate a problem on reflection and transmission of plane-waves at an interface between two dissimilar half-spaces of a transversely isotropic micropolar piezoelectric material. The entire model is assumed to rotate with a uniform angular velocity. The governing equations of rotating and transversely isotropic micropolar piezoelectric medium are specialized in a plane. Plane-wave solutions of two-dimensional coupled governing equations show the possible propagation of three coupled plane-waves. For an incident plane-wave at an interface between two dissimilar half-spaces, three reflected and three transmitted waves propagate with distinct speeds. The connections between the amplitude ratios of reflected and transmitted waves are obtained. The expressions for the energy ratios of reflected and transmitted waves are also obtained. A numerical example of the present model is considered to illustrate the effects of rotation on the speeds and energy ratios graphically.
Źródło:: Archives of Acoustics; 2021, 46, 4; 623-635
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: An Experiment of the Actual Vertical Resolution of the Sub-bottom Profiler in an Anechoic Tank
Autorzy:: Wang, Fangqi
Dong, Lifeng
Ding, Jisheng
Zhou, Xinghua
Tao, Changfei
Lin, Xubo
Liang, Guanhui
Powiązania:: https://bibliotekanauki.pl/articles/177846.pdf
Data publikacji:: 2019
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:: SBP
sub-bottom profiler
PW
pulse width
vertical resolution
DRE
duration of reflection event
Opis:: Sub-bottom profiler (SBP) is an acoustic instrument commonly used to survey underwater shallow geological structure and embedded objects whose most important performance parameter is the actual vertical resolution. This paper presented a methodology to measure and evaluate the actual vertical resolution of SBP based on an experiment in an anechoic tank, which was divided into three components: building of artificial geological model, measurement of acoustic parameters, and determination of actual vertical resolution of the acoustic profiles. First, the wedge-shaped geological model, whose thickness could be accurately controlled, was designed and built in an anechoic tank to try to directly measure the vertical resolution of SBP. Then, the acoustic pulse width of SBP was measured to calculate the theoretical general vertical resolution and extreme vertical resolution. Finally, based on the acoustic profiles obtained in the experiment, the method which was used to evaluate the actual vertical resolution by measuring the duration of reflection event was put forward. Due to comparing measurement data of different parameter settings of the SBP, the study has revealed that the SBP had the lowest resolution in the 4 kHz–500 μs setting, which was 226.5μs, or 36.2 cm, and the highest resolution in the 15 kHz–67 μs setting, which was 72.7 μs, or 11.6 cm. The vertical resolution decreased with the increase of the pulse width. The results also showed that the actual resolution was close to the theoretical general resolution and far from the extreme resolution.
Źródło:: Archives of Acoustics; 2019, 44, 1; 185-194
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Acoustic Panels Inspired by Nature
Autorzy:: Borkowski, Bartłomiej
Suder-Dębska, Katarzyna
Wiciak, Jerzy
Szlachta, Anna Maria
Powiązania:: https://bibliotekanauki.pl/articles/1953507.pdf
Data publikacji:: 2021
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:: acoustic panel
absorption
reflection
design process
lava cave
glacier cave
geometrical method
3D modelling
concept design
Opis:: The article presents the approach to the design process of acoustic panels based on the scientific research. This approach is based on combining the technical and the design competences to develop the innovative product value for the concept of acoustic panels. The article presents the concepts of two new acoustic panels – an absorbing and scattering panel and a panel reflecting sound waves. The first part of the article presents the starting point for the presented project – the acoustic research and the inspiration for both types of presented solutions. Next, the materials possible to use were discussed, which could reproduce the natural acoustic properties of the lava and glacier caves. The next part presents consecutive stages of the product development in a modern form, ensuring the expected acoustic properties. The last part of the article presents a fully functional solution and proposes further research and development directions.
Źródło:: Archives of Acoustics; 2021, 46, 1; 135-146
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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