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Wyświetlanie 1-4 z 4
Tytuł:
Estimation of Reverberation Time in Classrooms Using the Residual Minimization Method
Autorzy:
Nowoświat, A.
Olechowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/177635.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
reverberation time
Sabine's formula
classroom
residual minimization method
coefficient correcting the Sabine’s model
ODEON
Opis:
The objective of the residual minimization method is to determine a coefficient correcting the Sabine’s model. The Sabine’s equation is the most commonly applied formula in the designing process of room acoustics with the use of analytical methods. The correction of this model is indispensable for its application in rooms having non-diffusive acoustic field. The authors of the present paper will be using the residual minimization method to work out a suitable correction to be applied for classrooms. For this purpose, five different poorly dampened classrooms were selected, in which the measurements of reverberation time were carried out, and for which reverberation time was calculated with the use of theoretical methods. Three of the selected classrooms had the cubic volume of 258.5 m3 and the remaining two had the cubic volume of 190.8 m3. It was sufficient to estimate the correction for the Sabine’s equation. To verify the results, three other classrooms were selected, in which also the measurements of reverberation time were carried out. The results were verified by means of real measurements of reverberation time and by means of computer simulations in the program ODEON.
Źródło:
Archives of Acoustics; 2017, 42, 4; 609-617
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical and Experimental Analysis of the Response of a SAW Structure with WO3 Layers on Action of Carbon Monoxide
Autorzy:
Hejczyk, T.
Urbańczyk, M.
Pustelny, T.
Jakubik, W.
Powiązania:
https://bibliotekanauki.pl/articles/176885.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gas sensor
carbon monoxide (CO)
piezoelectric substrate
numerical modeling
surface acoustic waves
acoustoelectric effects
Ingebrigtsen's formula
Opis:
The paper presents the results of an analysis of gaseous sensors based on a surface acoustic wave (SAW) by means of the equivalent model theory. The applied theory analyzes the response of the SAW sensor in the steady state affected by carbon monoxide (CO) in air. A thin layer of WO3 has been used as a sensor layer. The acoustical replacing impedance of the sensor layer was used, which takes into account the profile of the concentration of gas molecules in the layer. Thanks to implementing the Ingebrigtsen equation, the authors determined analytical expressions for the relative changes of the velocity of the surface acoustic wave in the steady state. The results of the analysis have shown that there is an optimum thickness of the layer of CO sensor at which the acoustoelectric effect (manifested here as a change in the acoustic wave velocity) is at its highest. The theoretical results were verified and confirmed experimentally.
Źródło:
Archives of Acoustics; 2015, 40, 1; 19-24
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Analysis of Sensitivity of SAW Structure to the Effect of Toxic Gases
Autorzy:
Hejczyk, T.
Pustelny, T.
Wszołek, B.
Jakubik, W.
Maciak, E.
Powiązania:
https://bibliotekanauki.pl/articles/177695.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surface acoustics wave SAW
SAW
Ingebrigtsen’s formula
gas diffusion equations
gaseous acoustic sensors
numerical analyses of SAW structures
Opis:
The paper presents the results of numerical analysis of the SAW gas sensor in the steady and non-steady states. The effect of SAW velocity changes vs surface electrical conductivity of the sensing layer is predicted. The conductivity of the porous sensing layer above the piezoelectric waveguide depends on the profile of the diffused gas molecule concentration inside the layer. The Knudsen’s model of gas diffusion was used. Numerical results for the effect of gas CH4 on layers: WO3, TiO2, NiO, SnO2 in the steady state and CH4 in the non-steady state in recovery step in the WO3 sensing layer have been shown. The main aim of the investigation was to study thin film interaction with target gases in the SAW sensor configuration based on simple reaction-diffusion equation. The results of the numerical analysis allow to select the sensor design conditions, including the morphology of the sensor layer, its thickness, operating temperature, and layer type. The numerical results basing on the code elaborated numerical system (written in Python language), were analysed. The theoretical results were verified and confirmed experimentally.
Źródło:
Archives of Acoustics; 2016, 41, 4; 747-755
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and Numerical Acoustoelectric Investigation of the New SAW Structure with (RR)-P3HT Polymer in DMMP Detection
Autorzy:
Hejczyk, Tomasz
Wrotniak, Jarosław
Magnuski, Mirosław
Jakubik, Wiesław
Powiązania:
https://bibliotekanauki.pl/articles/1953456.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
gas sensor
numerical modelling
SAW gas sensor
Ingebrigtsen’s formula
DMMP
(RR)-P3HT
numerical acoustoelectric analysis
NAA
Opis:
This document presents the results of numerical analyses of the SAW gas sensor in the steady state. The effect of SAW velocity changes depending on how the surface electrical conductivity of the sensing layer is predicted. The conductivity of roughness sensing layer above the piezoelectric waveguide depends on the profile of the diffused gas molecule concentration inside the layer. Numerical results for the gas DMMP (CAS Number 756-79-6) for layer (RR)-P3HT in the steady state are shown. The main aim of the investigations was to study the thin film interaction with target gases in the SAW sensor configuration based on diffusion equation for polymers. Numerical results for profile concentration in steady state are shown. The results of numerical acoustoelectric analysis (NAA) allow to select the sensor design conditions, including the morphology of the sensor layer, its thickness, operating temperature and layer type. The numerical results based on the code written in Python, are described and analyzed. The theoretical results were verified and confirmed experimentally.
Źródło:
Archives of Acoustics; 2021, 46, 2; 313-322
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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