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Wyszukujesz frazę "acoustic parameter" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
Sensitivity Analysis of Acoustic Field Parameters on a Change of Boundary Conditions in a Room
Autorzy:
Suder-Dębska, K.
Czajka, I.
Czechowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/177639.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sensitivity analysis
acoustic parameter
geometrical method
sound absorption coefficient
noise of power machines
Opis:
The area of environmental protection concern minimises the impact that technical objects have on the environment. Usually the most effective way of protecting the environment is to influence the source of the problem. For this reason studies are conducted to modify the construction of machines, power machines in particular, so as to minimise their impact on the environment. In the case of environmental protection from noise it is most convenient to carry out measurements in an anechoic chamber. Unfortunately, this is possible only in very limited circumstances. In all other cases measurements are performed using an engineering method or the survey method, both of which are described in the standards and by taking into account the so-called environmental corrections. The obtained results are burdened with greater error than those of measurements in an anechoic chamber. Therefore, it would seem advantageous to develop a method of obtaining similar and reliable results as those in an anechoic chamber, but in a reverberant field. The authors decided to use numerical modelling for this purpose. The main objective of this work is a comprehensive analysis of the numerical model of a laboratory designed for acoustic tests of selected power machines. The geometry of a room comprising an area of analysis is easy to design. The main difficulty in modelling the phenomena occurring in the analysed area can be the lack of knowing the boundary conditions. Therefore, the authors made an attempt to analyse the sensitivity of various acoustic parameters in a room in order to change these boundary conditions depending on the sound absorption coefficient.
Źródło:
Archives of Acoustics; 2014, 39, 3; 343-350
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Solid Contamination in Ball Bearing Through Acoustic Emission Signals
Autorzy:
Sheriff, K. A. I.
Hariharan, V.
Kannan, T.
Powiązania:
https://bibliotekanauki.pl/articles/354100.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bearing
solid contamination
acoustic emission
signal parameter
Opis:
Acoustic emission is one of the effective techniques used for the condition monitoring of rolling element bearings. Contamination is one of the major reasons for bearing early failure due to presence of solid particle in lubricant grease. In most cases, outer race is stationary and the inner race is attached to the rotating assembly. The lubrication is very essential for the bearing to perform under various demanding conditions. The main aim of this project is to analyze the effect of contamination of lubricant by solid particles on the dynamic behavior of rolling bearing. Green sand at three concentration levels 5%, 15%, 25% and different particle sizes 75 μm, 106 μm and 150μm is used to contaminate the lubricant. Experimental tests have been performed for different load and speed condition in good and contaminated ball bearings lubricated with grease. The trends in the amount of AE waves affected by the contamination of the grease were determined. Acoustic emission signals were analyzed in terms of RMS, kurtosis, and peak-peak.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1871-1874
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Application of Acoustic Anisotropy to Evaluation of Material Properties
Autorzy:
Krysztofik, J.
Manaj, W.
Socha, G.
Powiązania:
https://bibliotekanauki.pl/articles/97961.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
nondestructive testing
acoustic birefringence
damage parameter
Inconel 718
Opis:
Structural properties of materials change under stress, temperature and work environment. These changes are generally unfavorable. They cause a reduction in strength of materials. This has an impact on the safety and service life of machines and constructions. In the chemical and petrochemical industry the destruction of a structure can be activated by chemical substances. In the energy industry, a key element in assisting the destruction is temperature. In aviation, the typical cause of damage is the process of fatigue. Regardless of the differences regarding/concerning the mechanisms of degradation, typical of the sectors of industry, the end result is the emergence of microvoids and microcracks in the material. In the final phase of the process, dominant cracks are formed. The term of measure of material damage, introduced by Kachanov and Rabotnow, can be effectively used also when considering the impact of microdamages on measurable macroscopic acoustic quantities. A damage parameter proposed by Johnson allows to correlate changes in acoustic birefringence of the material with the parameter describing the degree of damage. In this article the authors presented the nondestructive tests results concerning Inconel 718 alloy subjected to damage caused by plastic deformation. This paper focuses on the evaluation of acoustic properties in relation to the degradation of the materials tested.
Źródło:
Fatigue of Aircraft Structures; 2015, 7; 5-11
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic cylindrical cloak
Autorzy:
Premarathna, S. M.
Wijewardena Gamalath, K. A. I. L.
Powiązania:
https://bibliotekanauki.pl/articles/1192658.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Acoustic metamaterials
electromagnetic metamaterials
negative index
anisotropic’ cloaking
radially dependent FDTD method
reduced parameter model’ higher order parameter model
Opis:
Using the analogy between anisotropic acoustic metamaterials with magnetic metamaterials in transverse magnetic mode, an electromagnetic wave of 2 GHz n transverse magnetic mode, at normal incidence propagating through a two dimensional, anisotropic, semi infinite, double negative, metamaterial slab of 800 × 800 cells, embedded in free space, for the ideal loss case was simulated by a radially dependent finite difference time dependent method to study an ideal acoustic cylindrical cloak. For the simulations multiple cycle m-n-m pulses generating Gaussian beams were used as sinusoidal hard line sources. The simulations for acoustic cylindrical cloaking by a reduced parameter model and a higher order parameter model are also presented. The cloaking behaviour is largely dependent upon the transformation and not on the thickness of the cloak. The radial dependent model and the higher order transformation model are suited for acoustic cloaking.
Źródło:
World Scientific News; 2016, 47, 2; 75-88
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic emission as a method for the detection of fractures in the plant tissue caused by the external forces
Autorzy:
Zdunek, A.
Konstankiewicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/25704.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
potato tissue
deformation
stress level
acoustic emission
mechanical parameter
cell structure
plant tissue
Źródło:
International Agrophysics; 1997, 11, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of water potential on the failure of potato tissue
Autorzy:
Haman, J.
Konstankiewicz, K.
Zdunek, A.
Powiązania:
https://bibliotekanauki.pl/articles/25420.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
failure
production process
water potential
acoustic emission
mechanical parameter
quality
potato
tissue
plant material
Źródło:
International Agrophysics; 2000, 14, 2
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geochemical and acoustic evidence for the occurrence of methane in sediments of the Polish sector of the Southern Baltic Sea
Autorzy:
Brodecka, A.
Majewski, P.
Bolalek, J.
Klusek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/48640.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
methane
sulphate concentration
hydrogen sulphide
sediment
Baltic Sea
marine sediment
shallow sea
organic matter decomposition
water parameter
acoustic property
Źródło:
Oceanologia; 2013, 55, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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