PL
 |
EN
Ograniczanie wyników
Czasopisma help
  1. 8 Vibrations in Physical Systems
  2. 6 Archives of Acoustics
  3. 5 Czasopismo Techniczne. Mechanika
  4. 5 Technical Transactions. Mechanics
  5. 4 Materiały Budowlane
Więcej...
Autorzy help
  1. 7 Sikora J.
  2. 7 Turkiewicz J.
  3. 2 Chen S.
  4. 2 Chojak Aleksandra
  5. 2 Dulak L.
Więcej...
Lata help
  1. 1 2024
  2. 2 2023
  3. 4 2022
  4. 2 2021
  5. 1 2020
Więcej...
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 39

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  sound absorption coefficient
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
1
Content available remote Ocena właściwości akustycznych warstwy ścieralnej z asfaltu porowatego nawierzchni drogowych w warunkach laboratoryjnych
Gardziejczyk Władysław, Motylewicz Marek, Sakowski Mariusz
Materiały Budowlane
|
2024
|
nr 6
32--35
PL
Zastosowanie asfaltu porowatego w warstwie ścieralnej nawierzchni drogowej istotnie wpływa na obniżenie poziomu hałasu opona/nawierzchnia. Parametrami charakteryzującymi właściwości akustyczne warstwy ścieralnej są współczynnik pochłaniania dźwięku i wodoprzepuszczalność. W artykule przedstawiono analizę wyników badań współczynnika pochłaniania dźwięku oraz wodoprzepuszczalności mieszanek z asfaltu porowatego. Stwierdzono istotny wpływ zawartości wolnych przestrzeni w mieszance na wartości badanych parametrów.
EN
The use of porous asphalt in the wearing course of a road pavement has a significant effect on reducing tyre/road noise levels. The parameters characterising the acoustic properties of the wearing course are sound absorption coefficient and water permeability. This paper presents an analysis of the results of a study of the sound absorption coefficient and water permeability of porous asphalt mixtures. A significant influence of the air voids content of the mixture on the values of the parameters studied was found.
2
Content available The use of sound-absorbing properties of acoustic panels with different degree of perforation on the outer lining layer in modeling and calculations of traffic noise
Żuchowski Rafał, Nowoświat Artur, Pudełko Bartłomiej, Dulak Leszek
Vibrations in Physical Systems
|
2023
|
Vol. 34, nr 2
art. no. 2023219
EN
The article presents research studies on the impact of perforation of the outer lining layer of an acoustic panel used for the construction of road noise reduction devices on its absorbing properties. The research included measurements of the reverberation time in the laboratory conditions of diffusion field, on the basis of which the values of sound absorption coefficient as a function of frequency were determined. In addition, for various solutions of acoustic panels based on a corrugated fiber cement board on the top surface and on two types of mineral wool inside the panel, the αw and αp indices as well as sound absorption rating index DLαNRD were calculated. Then, computer simulations were carried out to show the influence of laboratory-determined acoustic parameters of the panels on the acoustic climate in the vicinity of a selected transport system. The key aspects of the modeling process are presented, the characteristics of the noise source and the analysis of the results are described. An important goal of traffic noise modeling is to strive to develop more friendly and sustainable material solutions that will reduce the negative effects of noise on people and the environment.
3
Content available The effect of sound-absorbing walls on the acoustic properties of the modelled unit cell of a sound-absorbing metamaterial
Chojak Aleksandra, Binek Wojciech, Chojnacki Bartłomiej, Pawlik Jan, Idczak Julia
Vibrations in Physical Systems
|
2023
|
Vol. 34, nr 2
art. no. 2023212
EN
Cavity-based metamaterials are usually designed for sound absorbing or sound scattering properties. They are built of combinations of ducts and slits, which in the case of acoustic absorbers are designed to maximize the sound absorption at resonance frequencies through the appearance of the viscothermal losses. The unit cells are designed under the assumption of perfectly rigid walls, shared by all the analytical models. Sound absorbing properties of the structures result from viscothermal losses in small ducts. The paper discusses the influence of adding sound absorption to the walls in the numerical model on the results of the observed sound absorption coefficient. It is demonstrated that the resulting sound absorption of the structure varies with changing sound absorption coefficient of the walls of the structure. The same observations are made for 3D-printed measurement samples, showing the importance of including the sound absorption of the walls in the modelling process.
4
Content available Experimental verification of similarity criteria for sound absorption of simple metamaterials
Chojak Aleksandra
Vibrations in Physical Systems
|
2022
|
Vol. 33, nr 2
art. no. 2022211
EN
The paper concerns the dimensional analysis of simple acoustic metamaterials and its experimental verification in a computer model. Due to their decreased thickness possible because of the thermoviscous losses and sound dispersion that occur in acoustic metamaterials, such structures are gaining popularity, both as sound absorbers and diffusers. This implies the need to find their equivalents to be used at scale - both for modeling interiors with metamaterials and developing more complicated structures. The paper discusses the dimensional analysis performed for a generalized unit cell of a metamaterial with a resonator. The dimensional analysis shows the need for scaling both the geometrical dimensions of the structure and the parameters of the medium - air. The dimensional analysis was derived based on the transfer matrix method and was proven correct with the finite element method model. The paper also discusses the consequences of neglecting the air criteria, which are impossible to be fulfilled. This opens the question of finding new criterial numbers allowing the correct reflection of acoustic metamaterials at scale.
5
Content available Comparative analysis of the acoustic properties of granular materials determined with the use of impedance tube
Kosała Krzysztof
Vibrations in Physical Systems
|
2022
|
Vol. 33, nr 3
art. no. 2022321
EN
The results of acoustic property tests for six types of granular materials: perlite, vermiculite, active coconut carbon, rubber granulates, pumice and wood chips, which can be used in noise protection structures, are shown in the article. The characteristics of the normal incidence sound absorption coefficient and the normal incidence sound transmission loss for material specimens with seven thicknesses in the range of 10-100 mm were determined based on the results of experimental tests carried out with the use of an impedance tube. The relationships between the first resonant absorption frequencies and the thicknesses of material specimens were determined. Single-number indices for the tested materials, in the form of the weighted sound absorption coefficients, were determined. Subsequently, dependencies of these indices on the surface mass of the tested materials were determined. The research showed that three materials, perlite, vermiculite and active coconut carbon, were distinguished among the examined granules with the best sound-absorbing and sound-insulating properties. Active coconut carbon had the best sound-insulating properties among the granular materials tested.
6
Content available Analysis of factors influencing the measurement result of the reverberant sound absorption coefficient under laboratory conditions
Czapla Marcjanna, Wszołek Tadeusz
Vibrations in Physical Systems
|
2022
|
Vol. 33, nr 1
art. no. 2022103
EN
There are still discrepancies in the measurement results despite the standardized methods of measuring the sound absorption coefficient in the reverberation room. They appear especially in interlaboratory tests. The research used the method included in the EN-ISO 354: 2003 standard to determine the sound absorption coefficient. The subject of scientific research was to investigate the impact of measurement techniques (Maximum Length Sequence method and interrupted noise method for both T20 and T30 evaluation ranges), humidity in the test room, sample seasoning and sample fitting, and finally the influence of room variability on the measurement results. The tests were performed in two reverberation chambers. The study included two types of materials. Samples (1) made of identical pieces of mineral wool (ISOVER glass wool and ROCKWOOL rock wool) and (2) of fibreboard. Mineral wool was of different thicknesses. Among the measurement techniques, the smallest dispersion of the reverberation time results was obtained with the MLS -T30 method, and the highest differences in the results were caused by the test being performed in another room (reverberation chamber). There was no significant influence with the increase in humidity or the careful arrangement of the test sample from the components on the measurement result.
7
Content available remote A Novel Theoretical Modeling for Predicting the Sound Absorption of Woven Fabrics Using Modification of Sound Wave Equation and Genetic Algorithm
Putra Valentinus Galih Vidia, Irwan, Wijayono Andrian, Mohamad Juliany Ningsih, Yusuf Yusril
Autex Research Journal
|
2022
|
Vol. 22, no. 1
108--122
EN
Woven fabric in Indonesia is generally known as a material for making clothes and it has been applied as an interior finishing material in buildings, such as sound absorbent material. This study presents a new method for predicting the sound absorption of woven fabrics using a modification of the wave equations and using genetic algorithms. The main aim of this research is to study the sound absorption properties of woven fabric by modeling using a modification of the sound wave equations and using genetic algorithms. A new model for predicting the sound absorption coefficient of woven fabric (plain, twill 2/1, rips and satin fabric) as a function of porosity, the weight of the fabric, the thickness of the fabric, and frequency of the sound wave, was determined in this paper. In this research, the sound absorption coefficient equation was obtained using the modification of the sound wave equation as well as using genetic algorithms. This new model included the influence of the sound absorption coefficient phenomenon caused by porosity, the weight of the fabric, the thickness of fabric as well as the frequency of the sound wave. In this study, experimental data showed a good agreement with the model.
8
Content available Experimental tests of the acoustic properties of sound-absorbing linings and cores of layered baffles
Kosała Krzysztof
Vibrations in Physical Systems
|
2021
|
Vol. 32, nr 1
art. no. 2021107
EN
The article presents the results of research on the acoustic properties of materials used as sound-absorbing linings and cores in baffles of anti-noise protection. Using an impedance tube the spectral characteristics of the normal incidence sound absorption and sound transmission loss indices of 12 specimens of mineral wool with different density and thickness were determined. From these characteristics, the single-number weighted sound absorption coefficient αw and the sound reduction index Rw were calculated. To calculate the value of the Rw index on the basis of surface mass of the mineral wool specimen, a new formula was proposed. The insertion loss of an acoustic enclosure with one, two and three-layer walls with dimensions of 0.7×0.7 m, containing mineral wool, was determined. The best efficiency was achieved for the enclosure made of walls of layers: mineral wool, placed on the sound source side, steel plate and aluminium plate.
9
Content available Application of the impulse response method in the test of acoustic properties of building materials
Piechowicz Janusz
Vibrations in Physical Systems
|
2021
|
Vol. 32, nr 2
art. no. 2021201
EN
Understanding the acoustic properties of the materials used in the construction of wall surfaces, plays an important role in structural and environmental acoustics. There are many research methods for determining the acoustic parameters of building elements, such as the sound absorption coefficient, the sound reflection coefficient, or the sound insulation index determined in the laboratory or in situ. This work focuses on the determination of the sound absorption coefficient and the possibility of its measurement in "in situ" conditions by the impulse response method. The main purpose of the presented research was to check whether it is possible to use the impulse method in a small reverberant room to determine the sound absorption coefficient of a small part of the wall structure.
10
Content available Method for Calculating the Sound Absorption Coefficient for a Variable Range of Incidence Angles
Yori Alfio
Archives of Acoustics
|
2020
|
Vol. 45, No. 1
67--75
EN
The theoretical estimation of sound absorption coefficient of a surface may give very different results. This will depend on the type of sound field assumed in the theoretical model used for the estimation of its sound absorption coefficient. Absorption coefficients for normal and diffuse sound fields are widely known, although they may be far from the absorption values given by an absorbing material when it is finally installed inside a room or enclosed space, where a sound field closer to a spherical wavefront is more likely to be found. This work presents a theoretical study, which is addressed at obtaining a mathematical expression to calculate the sound absorption coefficient for a variable range of incidence angles, called αs. The presented method uses a circular sound field incidence as an approximation to a spherical incidence. The estimation of this coefficient αs is based on obtaining the incident and reflected sound fields for a surface located facing a lineal source. The advantage of this calculation method over others lies on its capability to give results for circular, normal and random wave incidence depending on the range of incidence angles considered in the calculation.
11
Content available Assessment of sound absorbing properties of composite made of recycling materials
Gaj Patryk, Kopania Joanna, Wójciak Kamil, Bogusławski Grzegorz
Vibrations in Physical Systems
|
2019
|
Vol. 30, nr 1
art. no. 2019109
EN
In modern world we are searching methods to reuse most of industrial disposals produced during manufacturing. Some kinds of materials, like scraps from acoustic foam, however are not so easily utilized using recycling methods for its primary usage. Disposals produced during the manufacturing process can be compressed and reused as sound absorbing material. The purpose of this article is to examine sound absorbing properties of material made of acoustic foam disposals and compare it with sound protection materials, which are commonly used. Sound absorbing damping were tested using Kundt’s tube and reverberation room examination method. Tests were carried out according to standard PN-EN ISO 354:2005, for reverberation room examination, and according to Bruel&Kjaer electronic instruments technical manual for Kundt’s tube examination.
12
Content available remote Projektowanie adaptacji akustycznej otwartych pomieszczeń do prac administracyjnych. Część 1. Projektowanie podstawowe
Mikulski Witold
Materiały Budowlane
|
2019
|
nr 8
16--20
PL
Projektowanie akustyczne pomieszczeń biurowych open space polega na takim uwzględnieniu w pomieszczeniu różnych wyrobów dźwiękochłonnych, aby uzyskać wymagane przepisami warunki akustyczne. W artykule projektowanie podzielono na dwa etapy. Etap pierwszy, wymagany przez przepisy polskie, to uzyskanie w pomieszczeniu wymaganej chłonności akustycznej. Natomiast etap drugi polega na takiej aranżacji akustycznej pomieszczenia i stanowisk pracy, aby uzyskać w nim wymagane warunki propagacji (a właściwie separacji) dźwięków mowy między stanowiskami pracy. Zewzględu na objętość, artykuł podzielono na dwie części. W części pierwszej opisano pierwszy etap projektowania (podano metodę obliczeniową wg PN-B-02151-4:2015 i przykład). W części drugiej, w następnym artykule, opisany zostanie etap drugi projektowania wraz z podaniem przykładu (z wykorzystaniem programu ODEON).
EN
The acoustic design of the open plan office consists in taking into account various sound-absorbing products in the room to achieve the required acoustic conditions. In the article design is divided into two stages. The first stage, obligatory by Polish regulations, is to obtain the room's required sound absorption. The second stage consists in such an acoustic arrangement of the room and workstations to obtain the required conditions for the propagation (or actually separation) of speech sounds between workstations. Due to the volume, the article has been divided into two parts. The first part (this one) describes the first design stage (the calculation method according to PN-B-02151-4:2015 standard and example are given). In the second part, in the next article, the second design stage (using the ODEON software) will be described.
13
Content available remote Wpływ materiałów wykończeniowych na warunki akustyczne w pomieszczeniu
Olechowska M., Nowoświat A., Krause P.
Materiały Budowlane
|
2018
|
nr 12
3--5
PL
W artykule dokonano przeglądu wybranych wyrobów dźwiękochłonnych i przeanalizowano ogólne zasady ich stosowania w celu poprawy właściwości akustycznych pomieszczeń. W tym celu zestawiono wartości współczynników pochłaniania dźwięku wszystkich analizowanych wyrobów dźwiękochłonnych, a następnie zamodelowano w programie obliczeniowym ODEON przykładowe pomieszczenie, które poddawano adaptacji akustycznej (kolejno sufit, ścianę oraz podłogę) odpowiednio dobranym wyrobem wykończeniowym. Na tej podstawie określono wpływ danego wyrobu na poprawę właściwości akustycznych pomieszczenia.
EN
The article reviews selected sound absorbing products and analyzes the general principles of their use in order to improve the acoustic properties of rooms. For this purpose, the values of sound absorption coefficients of all the sound absorbing products analyzed were summarized and then, in the ODEON software, a sample room was made, which was subjected to acoustic adaptation (followed by the ceiling, wall and floor) of the primary room with a properly selected finishing product. On this basis, the impact of a given product on the improvement of the acoustic properties of the room was determined.
14
Content available remote Effect of Thickness, Density and Cavity Depth on the Sound Absorption Properties of Wool Boards
Qui H., Enhui Y.
Autex Research Journal
|
2018
|
Vol. 18, no. 2
203--208
EN
A novel wool absorption board was prepared by using a traditional non-woven technique with coarse wools as the main raw material mixed with heat binding fibers. By using the transfer-function method and standing wave tube method, the sound absorption properties of wool boards in a frequency range of 250-6300 Hz were studied by changing the thickness, density, and cavity depth. Results indicated that wool boards exhibited excellent sound absorption properties, which at high frequencies were better than that at low frequencies. With increasing thickness, the sound absorption coefficients of wool boards increased at low frequencies and fluctuated at high frequencies. However, the sound absorption coefficients changed insignificantly and then improved at high frequencies with increasing density. With increasing cavity depth, the sound absorption coefficients of wool boards increased significantly at low frequencies and decreased slightly at high frequencies.
15
Content available Effect of the composite temperature and humidity test on the sound absorption coefficient of fibrous materials used in automotive applications
Białkowski P., Zapart Ł., Krężel B.
Archiwum Motoryzacji
|
2018
|
Vol. 81, nr 3
29--38
EN
In this article an attempt to determine the effect of composite temperature and humidity test on the sound absorption coefficient for commonly used materials in vehicles is described. Three types of fibrous materials were selected. The absorption coefficient was determined for material samples and then the materials were tested with composite temperature and humidity test. After the test, the sound absorption coefficient was measured again. The difference between the absorption coefficients before and after the test shows the actual effect on the sound absorption. An impedance tube was used to determine the absorption coefficient. Results are presented in graphs and tables for three types of fibrous materials. The method of measurement is described and conclusions are drawn.
PL
W pracy przedstawiono próbę określenia wpływu temperatury i wilgotności na współczynnik pochłaniania dźwięku materiałów powszechnie stosowanych w samochodach. Do badań wybrano trzy rodzaje materiału włóknistego. Dla próbek materiału wyznaczono współczynnik pochłaniania dźwięku, a następnie próbki te poddano złożonej próbie temperatury i wilgotności. Po wykonaniu testu temperaturowo- wilgotnościowego ponownie wyznaczono współczynnik pochłaniania dźwięku. Różnica pomiędzy współczynnikami pochłaniania przed i po teście przedstawia rzeczywisty wpływ temperatury i wilgotności dla danej próbki materiału. Do wyznaczenia współczynnika pochłaniania dźwięku wykorzystano rurę impedancyjną. Wyniki przedstawiono w formie wykresów i tabel dla danego materiału. Opisano przebieg pomiarów oraz powstałe wnioski.
16
Content available Sound Absorption Behavior of Polyurethane Foam Composites with Different Ethylene Propylene Diene Monomer Particles
Zhu W., Chen S., Wang Y., Zhu T., Jiang Y.
Archives of Acoustics
|
2018
|
Vol. 43, No. 3
403--411
EN
Considering the environmental pollution caused by waste rubber, some measures should be taken to improve the utilization rate of waste rubber. In this study, the effect of Ethylene Propylene Diene Monomer (EPDM) particles in the polyurethane (PU) foams on sound absorption behavior is investigated for improving sound environment within vehicles and reducing the environment pollution. EPDM particles of different contents and hardness are used as fillers for producing foams with different pore morphologies and sound absorption properties. The results show that adding EPDM to foam would produce smaller pores, higher density and bigger air-flow resistivity. Simultaneously, there are better sound absorption properties of the PU foam composites in the medium frequency region, and the better value can be obtained at the lower frequency with the content of EPDM increasing. The hardness of EPDM also shows better influence on sound absorption properties, especially in the medium frequency region. It means the foam pore morphologies have influence on sound absorption properties.
17
Content available Identification of Sound Power Levels and Surface Absorption Coefficients in Multi-Source Industrial Buildings by Using a Simplified Diffusion Model
Sequeira M. E., Cortínez V. H.
Archives of Acoustics
|
2018
|
Vol. 43, No. 1
93--102
EN
This article deals with the identification of sound powers and absorption surface coefficients in multisource industrial buildings from the knowledge of the sound pressure levels (SPLs) at several monitoring points. This inverse problem is formulated as one of optimisation in which the objective function is the difference between the measured and predicted SPLs. The methodology combines the use of a simplified acoustic diffusion model with the simulated annealing optimisation technique. The former is a recently developed model for estimating the SPLs in a fast and sufficiently accurate form. The low computational cost of the model constitutes the major advantage for the optimisation procedure due to the great numer of simulations required. Numerical examples are given to show the efficiency of the proposed approach.
18
Content available Multi-Objective Optimization of Acoustical Properties of PU-Bamboo-Chips Foam Composites
Jiang Y., Chen S., Wang D., Chen J.
Archives of Acoustics
|
2017
|
Vol. 42, No. 4
707--714
EN
In this study, an effective optimization approach was proposed to improve acoustical behaviors of PU foams. The important parameters of PU foams: content of water, silicone oil and catalyst A1 were chosen and their effects on sound absorption coefficient and transmission loss of PU foams were studied by using Taguchi methods. In addition, bamboo chips were incorporated into PU foams as fillers to improve the acoustical properties of PU foams. Four controlled factors: the content of water, silicone oil, catalyst A1 and bamboo chips with three levels for each factor were chosen and Taguchi method based on orthogonal array L9 (34) was employed to conduct the experiments. Based on the results of Taguchi’s orthogonal array L9 (34), signal-to noise (S/N) analysis was used and developed to determine an optimal formulation of PU-bamboo-chips foam composites.
19
Content available remote Acoustic evaluation of a new modular system for green roofs and green walls
Manso M., Castro-Gomes J. P., Marchacz M., Górski M., Dulak L., Żuchowski R.
Architecture Civil Engineering Environment
|
2017
|
Vol. 10, no. 2
99--108
EN
Environmental noise is a major problem that affects citizen’s health and comfort mainly in densely populated urban areas. There are some ways to reduce environmental noise pollution through the use of materials with good acoustic insulation properties in buildings envelope. Recent studies have shown that green surfaces, e.g. in the form of green roofs and green walls, can contribute to decrease noise levels. The aim of this research is to identify how factors such as substrate and plants, variety and height of plants, affect the sound absorption of a modular system for green surfaces in simulated conditions. The results show that introduction substrate (S2) can improve the weighted sound absorption coefficient in 15% and the addition of plants (S3) improves it 20% more. However, if a variety of smaller and higher plants is used (S4) the weighted sound absorption coefficient (αw) can reach to 0.80 and an absorption class B can be obtained.
PL
Hałas środowiskowy jest jednym z ważniejszych problemów wpływających na zdrowie i komfort życia mieszkańców miast, szczególnie na terenach gęsto zaludnionych. Jest kilka sposobów ograniczania zanieczyszczenia hałasem środowiskowym poprzez stosowanie materiałów elewacyjnych o dobrych parametrach akustycznych. Wiele opracowań pokazuje, iż powierzchnie zielone, np. w formie zielonych dachów czy zielonych ścian, mogą przyczyniać się do obniżenia poziomu hałasu. Przedmiotem opracowania jest wskazanie jak czynniki takie jak podłoże, roślinność oraz zróżnicowanie wysokości roślin wpływa na pochłanianie dźwięku przez modułowy system powierzchni zielonych w warunkach laboratoryjnych. Wyniki wskazują, iż wypełnienie podłożem (S2) może poprawić jednoliczbowy wskaźnik pochłaniania dźwięku (αw) o 15%. Udział roślinności (S3) poprawia ten parametr o ponad 20%. W przypadku wariantu zawierającego mniejszą i większą roślinność (S4) jednoliczbowy wskaźnik pochłaniania dźwięku (αw) może osiągać wartości do 0.80 oraz klasę pochłaniania B.
20
Content available Analiza możliwości redukcji hałasu we wnętrzach urbanistycznych poprzez zastosowanie elementów zieleni na elewacji budynku
Dulak L., Marchacz M., Żuchowski R.
Fizyka Budowli w Teorii i Praktyce
|
2016
|
T. 8, nr 2
9--12
PL
Praca zawiera ocenę możliwości oraz wyniki obliczeń po zastosowaniu zieleni jako pokryć elewacyjnych mających na celu redukcję poziomów hałasu w założonym wnętrzu urbanistycznym. Wybrane rozwiązania materiałów o właściwościach dźwiękochłonnych zaczerpnięto z literatury. W artykule wykorzystano również charakterystykę pochłaniania dźwięku dla jednej z fasad, którą wyznaczono we własnym zakresie w warunkach laboratoryjnych dla nowego materiału. Wszystkie wykorzystane w analizach charakterystyki pochłaniania wyznaczone zostały w oparciu o metodologię normową zawartą w [1] z wskazanymi zastrzeżeniami.
EN
This paper presents the evaluation of using green surfaces on facades to reduce noise levels in urban interiors. Some kinds of acoustic materials with well attenuated properties were taken from literature review. Acoustic parameters for one of the material solution were determined by laboratory measurements. All sound absorption characteristics used in the paper were determined by using standard [1] with recommendations.
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.