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Wyszukujesz frazę "acoustic effects" wg kryterium: Wszystkie pola


Tytuł:
New Approach to the Uncertainty Assessment of Acoustic Effects in the Environment
Autorzy:
Batko, W.
Pawlik, P.
Powiązania:
https://bibliotekanauki.pl/articles/177204.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
interval arithmetic
uncertainty
railway noise
Opis:
The acoustic climate assessment needed for the selection of solutions (technical, legal and organisa- tional), which will help to minimise the acoustic hazards in the analysed areas, is realised on the basis of acoustic maps. The reference computational algorithms, assigned to them, require very thorough prepa- ration of input data for the considered noise source model representing – in the best possible way – the acoustic climate. These input data are burdened with certain uncertainties in this class of computational tasks. The uncertainties are related to the problem of selecting proper argument values (from the inter- val of their possible variability) for the modelled processes. This situation has a direct influence on the uncertainty of acoustic maps. The idea of applying the interval arithmetic for the assessment of acoustic models uncertainty is formulated in this paper. The computational formalism assigned to the interval arithmetic was discussed. The rules of interval estimations for the model solutions determining the sound level distribution around the analysed noise source – caused by possible errors in the input data – were presented. The application of this formalism was illustrated in uncertainty assessments of modelling acoustic influences of the railway noise linear source on the environment.
Źródło:
Archives of Acoustics; 2012, 37, 1; 57-61
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A System for Management of Urbanized Areas in the Aspect of Acoustic Effects
Autorzy:
Kompała, J.
Powiązania:
https://bibliotekanauki.pl/articles/177475.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
environment
noise
system
management
optimization
Opis:
Within the boundaries of many municipal urbanized areas, large grounds are found, from which the noise is emitted into the environment, surrounded by the regions liable to acoustic protection. Such a condition generates many problems including also those ones related to the lack of the fulfillment of requirements concerning environmental protection against excessive noise. Therefore the aim of vital importance is the proper management of municipal grounds, both in view of the investment in policy steering, especially of new investments, and in the case of activities aimed at maintaining or restoring (revitalizing) the acoustic properties on the grounds that have already been used or simply degraded before. Keeping the scale of the problem in mind, such activities must be carried on not temporarily, but must have a systemic character. The structure of every system is characterized by the appropriate relationships among their elements and the properties of those relationships. In case of the noise management system, the elements of such a system are the activities connected with the management itself that are the actions which rely on specifying the aims and causing their realization within the scope and on the grounds subject to the managing entity. The superior aim of such activities should be to supply the tools for improvement of management and in the process of taking decisions that relate to investments including the of optimization conditions and maintenance of socio-economic importance of such areas.
Źródło:
Archives of Acoustics; 2011, 36, 1; 57-63
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A review of flow acoustic effects on a commercial automotive exhaust system - methods and materials
Autorzy:
Mohamad, Barhm
Powiązania:
https://bibliotekanauki.pl/articles/95223.pdf
Data publikacji:
2019
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
internal combustion engine
exhaust gas system
two-source method
two-load method
acoustic analysis
computational fluid dynamics
tłokowy silnik spalinowy
układ wydechowy silnika
metoda dwóch źródeł
analiza akustyczna
obliczeniowa mechanika płynów
Opis:
Literature review on flow acoustic methods and materials of an automotive muffler. A car is judged comfortable also depending on the acoustic level transmitted inside, and a thorough knowledge of acoustics of ducts and mufflers is needed for the design of efficient muffler configurations. Unstable exhaust gas at high temperature flowing from internal combustion engine manifold may cause of noise and vibrations conflicting with the high standard of acoustic comfort requested by this kind of vehicle. The basic gaols are to define most important methods to identify noise occur from the motion of fluid in case of turbulent model. Materials properties like velocity, temperature, thermal conductivity and density have been technical presented in this work.
Źródło:
Journal of Mechanical and Energy Engineering; 2019, 3, 2; 149-156
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Certain Problems Concerning Environmental Impact Assessment of Wind Turbines in Scope of Acoustic Effects
Autorzy:
Wszołek, T.
Kłaczyński, M.
Mleczko, D.
Ozga, A.
Powiązania:
https://bibliotekanauki.pl/articles/1197516.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.58.+z
43.66.Lj
87.50.Y-
Opis:
The paper deals with difficulties that are encountered by investors and decision-making authorities in the course of investment processes involving construction of wind power plants. Moreover, attention is focused on absence of standardized procedures that could be used to determine environmental impact of wind turbines, mainly in the scope of acoustic effects appearing in conditions typical for operation of such devices (strong wind), high elevation of related noise sources, and the nature of the sound emission (tonality and amplitude modulation). Lack of such procedures is a source of serious ambiguities developing in assessment of all investment stages - planning and forecasting, construction, and operation. An additional problem arises in the case of power plants located in the vicinity of Natura 2000 area, where construction projects are often obstructed on the grounds of unclear criteria concerning, among other things, the effect of acoustic phenomena on birds, bats, and other animals. It follows from the research presented in this paper that the consistent system of procedures and criteria should be worked out on the grounds of long-term monitoring studies.
Źródło:
Acta Physica Polonica A; 2014, 125, 4A; A-38-A-44
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Curvature Shape of Transparent COVID-19 Protective Face Shields on the Speech Signal
Autorzy:
Bjelić, Miloš
Mijić, Miomir
Miljković, Tatjana
Šumarac Pavlović, Dragana
Powiązania:
https://bibliotekanauki.pl/articles/31339743.pdf
Data publikacji:
2024
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
acoustic effects
COVID-19
curvature
face shield
pandemic
protection
speech
Opis:
Recent papers and studies over the course of last three years have shown that COVID-19 has a negative impact on the speech communication quality between people. This paper presents an influence analysis of the curvature shape of protective transparent shields on the speech signal. Five shields made of the same material and dimensions but with different curvatures were analyzed, from a completely flat to a very curved shield which has the same shape of curvature at its top and bottom and covers the entire face. The influence of the shield is analyzed with two types of experiments – one using dummy head with integrated artificial voice device, and the other using real speakers (female and male actors). It has been shown that usage of protective shields results in a relative increase in the speech signal level, in the frequency range of around 1000 Hz, compared to the situation when protective shields are not used. The relative increase in speech signal levels for large-curvature shields can be up to 8 dB. The possible causes of this phenomenon have been analyzed and examined.
Źródło:
Archives of Acoustics; 2024, 49, 1; 27-35
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The assessment of acoustic effects of exploited road vehicles with the use of subjective features of sound
Ocena efektów akustycznych eksploatowanych pojazdów drogowych z wykorzystaniem subiektywnych cech dźwięku
Autorzy:
Paszkowski, Waldemar
Powiązania:
https://bibliotekanauki.pl/articles/1365241.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
acoustic effect
sound features
road vehicles
modeling
vibroacoustics
efekt akustyczny
cechy dźwięku
pojazdy drogowe
modelowanie
wibroakustyka
Opis:
The article proposed an original way to assess the acoustic effects of road vehicles in the environment, with the use of selected methods of sound modeling and simulation. The taken solution presents a way of estimating the acoustic emission to the environment, from the exploited road vehicles, using subjective sound features. In ongoing studies, it is assumed to analyze and evaluate the sound features in the following order: source - propagation way - receiver. The distribution of these features in the time and frequency domains depends on generation, propagation and immission of acoustic energy, by the partial sources of the vehicle. The obtained information in the form of an acoustic signal can be represented by physical and subjective features of the sound. The undertaken research include the use of subjective features of sound in the assessment of acoustic effects of road vehicles exploited in the environment. The developed method was verified using modeling and simulation methods based on recorded acoustic signals in an urbanized environment.
W artykule zaproponowano oryginalny sposób oceny efektów akustycznych pojazdów drogowych w środowisku, z zastosowaniem wybranych metod modelowania i symulacji dźwięku. Podejmowane rozwiązanie przedstawia sposób oszacowania emisji akustycznej do środowiska od eksploatowanych pojazdów drogowych przy wykorzystaniu subiektywnych cech dźwięku. W realizowanych badaniach zakłada się analizę i ocenę cech dźwięku w układzie: źródło-droga propagacji-odbiornik. Rozkład tych cech w dziedzinie czasu i częstotliwości uzależniony jest od generowania, propagacji i immisji energii akustycznej przez źródła cząstkowe pojazdu. Otrzymana informacja w postaci sygnału akustycznego reprezentowana może być cechami fizycznymi i cechami subiektywnymi dźwięku. Podejmowane badania obejmują sposób wykorzystania subiektywnych cech dźwięku w ocenie efektów akustycznych eksploatowanych pojazdów drogowych w środowisku. Opracowany sposób zweryfikowany został za pomocą metod modelowania i symulacji na podstawie zarejestrowanych sygnałów akustycznych w środowisku zurbanizowanym.
Źródło:
Eksploatacja i Niezawodność; 2019, 21, 3; 522-529
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Suppression of nonlinear effects in acoustic resonators
Autorzy:
Červenka, M.
Bednařik, M.
Koniček, P.
Powiązania:
https://bibliotekanauki.pl/articles/332461.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
This paper deals with description of finite-amplitude standing waves in both closed and semi-closed resonaiors. Numerical solutions of second-order one-dimensional model equation are used. The nonlinear standing waves are generated by a piston or shaker. Numerical results ol multifrequency driving technique for suppressing of higher harmonics are presented.
Źródło:
Hydroacoustics; 2000, 3; 73-78
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Acoustic Treatment on Music Teachers’ Exposure to Sound
Autorzy:
Kozłowski, E.
Młyński, R.
Powiązania:
https://bibliotekanauki.pl/articles/177728.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
music teachers
sound pressure level
acoustic treatment
Opis:
In this study, music teachers’ exposure to sound was tested by measuring the A-weighted equivalent sound pressure level (SPL), the A-weighted maximum SPL and the C-weighted peak SPL. Measurements were taken prior to and after acoustic treatment in four rooms during classes of trumpet, saxophone, French horn, trombone and percussion instruments. Results showed that acoustic treatment affects the exposure of music teachers to sound. Daily noise exposure levels (LEX, 8 h) for all teachers exceeded a limit of 85 dB while teaching music lessons prior to room treatment. It was found that the LEX, 8 h values ranged from 85.8 to 91.6 dB. The highest A-weighted maximum SPL and C-weighted peak SPL that music teachers were exposed to were observed with percussion instruments (LAmax = 110.4 dB and LCpeak = 138.0 dB). After the treatments, daily noise exposure level decreased by an average of 5.8, 3.2, 3.0, 4.2 and 4.5 dB, respectively, for the classes of trumpet, saxophone, French horn, trombone and drums, and did not exceed 85 dB in any case.
Źródło:
Archives of Acoustics; 2014, 39, 2; 159-163
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Uniform stability in structural acoustic systems with thermal effects and nonlinear boundary damping
Autorzy:
Lasiecka, I.
Lebiedzik, C.
Powiązania:
https://bibliotekanauki.pl/articles/206079.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
nonlinear boundary damping
structural acoustic model
thermoelastic plates
uniform stabilization
Opis:
The stabilization problem for a structural acoustic model is considered. The model under consideration is that of acoustic cavity (wave equation) coupled at the interface with a flexible wall (plate equation) which accounts for thermal effects. It is shown that frictional, nonlinear damping applied at the boundary of the acoustic chamber provides the uniform decay rates for the energy function of the overall structure. The main novelty of this result, with respect to the literature, is that the uniform stability for the model is established without assuming any mechanical damping the wall.
Źródło:
Control and Cybernetics; 1999, 28, 3; 557-581
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efekty obróbki akustycznej ciekłej stali we wlewnicy
Effects of acoustic treatment of liquid steel in mould
Autorzy:
Nowacki, K.
Kania, H.
Powiązania:
https://bibliotekanauki.pl/articles/181620.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Metalurgii Żelaza im. Stanisława Staszica
Tematy:
obróbka akustyczna
wlewek stalowy
krzepnięcie
makrostruktura
acoustic treatment
solidification
steel ingot
macrostructure
Opis:
Problemem podczas produkcji konwencjonalnych wlewków stalowych odlewanych do wlewnic jest uzyskanie odpowiedniej jednorodności chemicznej w całej objętości wlewka. Metodą zmniejszenia segregacji pierwiastków w procesie ciągłego odlewania stali jest zastosowanie mieszania elektromagnetycznego. Innym, lecz znacznie droższym sposobem poprawy jakości wewnętrznej półwyrobów przeznaczonych do dalszej przeróbki plastycznej jest zastosowanie procesu przetapiania elektrożużlowego. Innowacyjną metodą oddziaływania na proces krzepnięcia konwencjonalnych wlewków stalowych może być wykorzystanie fal ultradźwiękowych o określonej mocy i częstotliwości. Wynikiem przeprowadzonych doświadczeń dot. oddziaływania ultradźwięków na stal krzepnącą we wlewnicy w skali półprzemysłowej, była poprawa jednorodności chemicznej wlewka, zwiększenie udziału kryształów równoosiowych w jego objętości oraz wzrost twardości stali.
The achievement of proper chemical homogeneity within the entire ingot volume during the manufacturing of conventional steel ingots cast into moulds is a problem. A method for reduction in segregation of elements during continuous casting of steel is the application of electromagnetic stirring. Another, but much more expensive method for improvement in internal quality of semi-products intended for further plastic working is the use of electroslag remelting process. An innovative method to affect the solidification of conventional steel ingots may be the use of ultrasound waves of specific power and frequency. The result of the experiments on the impact of ultrasounds on steel solidifying in the ingot mould in semi-industrial scale was the improvement in chemical homogeneity of ingot, increase in the share of equiaxed crystals in its volume and increase in steel hardness.
Źródło:
Prace Instytutu Metalurgii Żelaza; 2012, T. 64, nr 2, 2; 14-17
0137-9941
Pojawia się w:
Prace Instytutu Metalurgii Żelaza
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization problems for structural acoustic models with thermoelasticity and smart materials
Autorzy:
Lasiecka, Irena
Powiązania:
https://bibliotekanauki.pl/articles/729240.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
structural acoustic model with thermal effects
optimal control problem
smart controls
nonstandard Riccati equations
analyticity of semigroups
Opis:
Optimization problem for a structural acoustic model with controls governed by unbounded operators on the state space is considered. This type of controls arises naturally in the context of "smart material technology". The main result of the paper provides an optimal synthesis and solvability of associated nonstandard Riccati equations. It is shown that in spite of the unboundedness of control operators, the resulting gain operators (feedbacks) are bounded on the state space. This allows to provide full solvability of the associated Riccati equations. The proof of the main result is based on exploiting propagation of analyticity from the structural component of the model into an acoustic medium.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2000, 20, 1; 113-140
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on the Effects of Acoustic Liner Variation and Geometry Discontinuities on the Acoustic Performance of Lined Ducts
Autorzy:
Dhief, Raja
Makni, Amine
Taktak, Mohamed
Chaabane, Mabrouk
Haddar, Mohamed
Powiązania:
https://bibliotekanauki.pl/articles/177513.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
absorbent systems effect
discontinuities effect
scattering matrix
acoustic power attenuation
Opis:
Noise reduction inside waveguide systems has gained momentum owing to a great interest in it. To attenuate the sound in a broad frequency range, this study aims to compare the effects of two acoustic liners, a perforated plate backed by an air cavity (PP-Air cavity), or by a porous material (PP-PM), on the acoustic behaviour of lined ducts using a numerical model to compute the multimodal scattering matrix. From this matrix, the reflection and the transmission coefficients are computed and therefore the acoustic power attenuation is deduced. Moreover, the effects of geometry of ducts with and without changes in the section are investigated. The numerical results are obtained for five configurations, including cases of narrowing and widening of a duct portion with sudden or progressive discontinuities. Accordingly, numerical coefficients of reflection and transmission as well as the acoustic power attenuation show the relative influence of acoustic liners in each type of configuration.
Źródło:
Archives of Acoustics; 2020, 45, 1; 49-66
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of ship motion on acoustic remote sensing
Autorzy:
Tegowski, J.
Zielinski, A.
Powiązania:
https://bibliotekanauki.pl/articles/332057.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
ship motion
acoustic remote sensing
Opis:
Ship motion affects quality of acoustic data collected by various acoustic remote sensing systems used for bottom and fisheries surveying. The angular position of an acoustic beam changes in time from its nominal position vertical to sea surface. This motion affects the acoustic returns from the bottom and other targets by changing their intensity and arrival times. In this paper we illustrate these effects on bottom returns obtained using single beam sonar.
Źródło:
Hydroacoustics; 2003, 6; 205-214
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effects of Trunk Cavity and Air-Gaps in the Acoustic Response of a Passenger Vehicle
Autorzy:
Oktav, A.
Powiązania:
https://bibliotekanauki.pl/articles/950216.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustic coupling
acoustic eigenfrequencies
acoustic modes
acoustic response
air-gap
cabin cavity
Helmholtz resonator
passenger vehicle
trunk cavity
wave number
Opis:
The effects of additional cavities and air-gaps in the acoustic response of a passenger vehicle are investigated. It is observed that the cabin cavity and the trunk cavity of the passenger vehicle are connected through an aperture in the rear seat. In the trunk cavity of the vehicle, there are two more air-gaps which are designed as countermeasures to trunk lid slam noise. It is established that acoustic modes and acoustic eigenfrequencies of the vehicle are altered through the trunk cavity and its air-gaps. To develop an analytical solution, the actual acoustic cavity is simplified into a rectangular shape. In the analytical solution, the coupling of trunk and cabin cavities is considered. It is shown that the computational analysis results match well with the results of the analytical solution proposed. Further, the resonator effect of air-gaps present in the trunk cavity is examined.
Źródło:
Archives of Acoustics; 2017, 42, 3; 433-440
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Construction Changes in the Teeth of a Gear Transmission on Acoustic Properties
Autorzy:
Wieczorek, A.
Powiązania:
https://bibliotekanauki.pl/articles/90168.pdf
Data publikacji:
2012
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
gear
tooth height
gear contact ratio
sound pressure level
Opis:
This paper presents results of experimental research on the acoustic properties of gear wheels with high-profile teeth with differentiated tooth height. Those results showed that gear transmissions with high-profile teeth have the best acoustic properties, with the value of the transverse contact ratio εα ≈ 2.0. They also showed that a reduction in tooth height, and thereby in contact ratio, increased the sound pressure level.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2012, 18, 4; 499-507
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł

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