Temat: low frequency waves - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Badania i ocena uciążliwości hałasu niskoczęstotliwościowego w czterokondygnacyjnym budynku mieszkalnym
Investigations and analysis of low frequnecy troublesome in a fourstorey living house
Autorzy:: Wiciak, J.
Powiązania:: https://bibliotekanauki.pl/articles/328113.pdf
Data publikacji:: 2005
Wydawca:: Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:: fale niskoczęstotliwościowe
identyfikacja źródeł hałasu
low frequency waves
noise source identification
Opis:: W pracy przedstawiono badania i ocenę hałasu niskoczęstotliwościowego występującego w wybranym czterokondygnacyjnym budynku mieszkalnym. Ocenę warunków akustycznych występujących w badanym budynku przeprowadzono w oparciu o Instrukcję ITB 358/98.
The paper presents results and analysis of investigations of low frequency noise sources, existing in living houses. The results of noise measurements in building were carried out according to instruction ITB 358/98.
Źródło:: Diagnostyka; 2005, 36; 109-116
1641-6414
2449-5220
Pojawia się w:: Diagnostyka
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Effects of warmness and spatial nonuniformity of plasma waveguide on periodic absolute parametric instability
Autorzy:: Zaki, N. G.
Bekheit, A. H.
Powiązania:: https://bibliotekanauki.pl/articles/147605.pdf
Data publikacji:: 2011
Wydawca:: Instytut Chemii i Techniki Jądrowej
Tematy:: periodic absolute parametric instability (API)
low frequency waves
warm plasma
growth rate
dispersion equation
Opis:: The periodic absolute parametric instability (API) of the low-frequency oscillations excited by a monochromatic pumping field of an arbitrary amplitude in a warm 1-D (one-dimensional) nonuniform magnetoactive plasma is investigated. The separation method can be used for solving the two-fluid plasma equations describing the system. By applying this method we were able to determine the frequencies and growth rates of unstable modes and the self-consistent electric field. Plasma electrons are considered to have a thermal velocity. Different solutions for the spatial equation can be obtained the following cases: A) API in a uniform plasma, B) API in a nonuniform plasma. The latter has been studied here for two cases: B.1) the exact harmonic oscillator and B.2) the bounded harmonic oscillator (a bounded plasma). An increment has been found in the build-up of the oscillations, and it has been shown that the spatial nonuniformity of the plasma exerts the stabilizing effect on the parametric instability. A reduced growth rate of API in the warm plasma, in comparison to the cold plasma, is reported. It has also been found that the warmness of the plasma has no effect on the solution of the space part of the problem (only through the separation constant).
Źródło:: Nukleonika; 2011, 56, 4; 305-309
0029-5922
1508-5791
Pojawia się w:: Nukleonika
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Noise Control Transmission Methods of the Combustion Engine by Means of Reduction of the Vibration
Autorzy:: Žiaran, S.
Chlebo, O.
Powiązania:: https://bibliotekanauki.pl/articles/176754.pdf
Data publikacji:: 2016
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: combustion engine
low frequency waves
transmission
health
measures
silnik spalinowy
fale niskiej częstotliwości
skrzynia biegów
zdrowie
środki
Opis:: Transmission of vibroacoustic energy from an internal combustion engine (ICE) to its surroundings largely depends on how it is mounted, on available transmission paths and on the construction of the vehicle body and/or its surrounding structures. This is especially true in low speed engines in enclosed areas which generate perceptually weak noise, but strong low-frequency waves which energy has a negative impact on human health, comfort and driving safety especially in prolonged exposure to the source. The primary aim of the article was to analyse components of the ICE unit which had a determining impact on the reduction of low-frequency waves. Thus, the structurally transmitted noise from the ICE to its surrounding structure (body of the passenger vehicle) was analysed. The results of the vibroacoustic measurements were compared to modal analysis in order to determine possible resonance sources in the vehicle body and/or for assessing the influence of the vehicles safety gear on the generated vibroacoustic energy transfer into the cabin area of the passenger vehicle. Measurements were made for a passenger vehicle at rest and operating in its most common operational speed as well as for the stationary ICE of a cogenerate unit (CGU). Measurements and FFT analysis were used for the detection of the vibroacoustic energy sound pressure level (noise) and mechanical vibration. Firstly, the low-frequency noise sources were determined and their direct effects on the human body were investigated. Finally, this paper suggests some measures which may contribute to the reduction of undesirable vibroacoustic energy in enclosed areas.
Źródło:: Archives of Acoustics; 2016, 41, 2; 277-284
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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