Following the requirements of ISO 10140, to determine the acoustic insulation, measurements of the sound pressure levels in the source (L1) and receiving (L2) rooms and the reverberation time measurements in the receiving room (T) should be performed. However, the standard does not indicate the measuring signal to be used for the measurements. Various measurement methods can be used, including the use of the broadband noise or MLS method. The article examines the influence of the applied measurement methodology on the determined spectra of acoustic insulation and the weighted sound reduction index Rw. The total uncertainty of determining the acoustic insulation properties and partial uncertainties in determining L1, L2 and T were also calculated. The analysis of the obtained results allows concluding that the applied measurement method has no significant impact on the obtained acoustic insulation values, and the obtained measurement differences may rather be the result of an insufficient sample size.
The diffraction phenomenon at the edge of the acoustic screen is of fundamental importance for forming the acoustic shadow area in the space outside the screen. The so-called added devices construction solutions are increasingly used on plane sound barriers, often used as anti-noise solutions on roads and railway lines. Added devices with various geometric shapes; aim to change the diffraction conditions at the noise-reducing devices' top edge. Adrienne method was developed in a European research project, the aim of which was the measurement on site of sound absorption and sound transmission of any road noise barrier. The European Adrienne project has developed a diffraction difference index at the top edge of an acoustic screen and a method for its determination to compare the effectiveness of the screen with and without the added device. The diffraction difference index is a single-number rating of the design solution mentioned. Measurements for index calculations are made by comparing the impulse response of screens with and without the added device using MLS (Maximum Length Sequence) signals.
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Podczas rekonstrukcji wypadku drogowego ekspert coraz częściej może wykorzystywać filmy powstałe podczas wypadku. Filmy te są wykonywane przy użyciu automatycznych, stacjonarnych i mobilnych rejestratorów. Celem tego artykułu jest przedstawienie metody zwanej przez autora metodą „poruszającego się wzorca długości” (MLS), która służy do precyzyjnego określania prędkości pojazdów.
EN
During the reconstruction of a road accident, an expert can increasingly use movies created during a road accident. These films are made using automatic, stationary and mobile recorders. The purpose of this article is to present a method called by the author a “movable length standard” (MLS), which is used to accurately determine the speed of vehicles.
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Filmy wykonywane przy użyciu automatycznych, stacjonarnych i mobilnych rejestratorów coraz częściej są materiałem służącym do rekonstrukcji wypadku drogowego. Celem tego artykułu jest przedstawienie sposobu postępowania dla ustalenia prędkości pojazdu wymijającego się z pojazdem wyposażonym w kamerę wideo.
EN
Films made with automatic, stationary and mobile recorders are increasingly often used in road accident reconstruction. The aim of this article is to show how to accurately determine the speed of an oncoming vehicle equipped with a video recorder.
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