Wyniki wyszukiwania - Biblioteka Nauki

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The Analysis of Hospital Helicopter Landing Sites Location in Terms of their Vibroacustic Impact

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Chyla A. , Bukała M.

Transactions on Aerospace Research

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2019

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tom Nr 3 (256)

43--56

EN

According to the applicable regulations, in the case of a decision on the location of an investment consisting in the construction and commissioning of a helicopter landing field, it is necessary to carry out an environmental impact assessment. At the same time, due to the emission of noise related to the expected change of acoustic climate parameters, the indicators required under the applicable law related to building acoustics and also impact of vibration on the structure of buildings should be taken into account. The article discusses particular groups of issues related to the assessment of the impact of helicopter landing field on the environment and the hospital building. On the basis of the presented results of analyzes, a postulate concerning the necessity of introducing a comprehensive assessment methodology, including specific groups of issues, was formulated.

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Initial assumptions for the system of automatic detection and classification of aircraft noise events

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Bukała M. , Nowoświat A. , Chyla A.

Vibrations in Physical Systems

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2022

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tom Vol. 33, nr 2

art. no. 2022208

EN

The present study undertakes the development and implementation of an algorithm for an automatic separation of acoustic events related to aircraft flights. The data are provided by noise monitoring stations operating as part of multi-point continuous noise measurement systems around small and medium-sized airports and helicopter landing sites in Poland. The article presents initial assumptions of the developed method based on the conclusions of the research. For this purpose, two different methods of airborne noise signal detection will be discussed. The first method is based on the analysis of the value of the changing rate of the signal being the difference between the value of the analysed sample and the value of the h-th previous sample of the recorded sound level time history. The second method uses a convolutional neural network operating on values recorded in 1/3-octave bands. The objective of the study is to examine the effectiveness and limitations of the selected methods on the collected representative input data.

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Wpływ warunków otoczenia na wyznaczanie izolacyjności akustycznej przegród budowlanych techniką natężeniową w badaniach in situ

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Nowoświat A. , Bukała M. , Chyla A.

Materiały Budowlane

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2023

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tom nr 8

42--45

PL

W ramach opisanych badań przeprowadzono pomiary izolacyjności akustycznej fragmentu ściany pomieszczenia w warunkach in situ, którego czas pogłosu w rejonie badanej próbki był modyfikowany przez zastosowanie materiału pochłaniającego falę akustyczną i wynosił 1,09 s lub 1,71 s. Przeprowadzone pomiary wykazały istotny wpływ zmiany parametrów pogłosowych pomieszczenia na normowe wskaźniki oceny pola, a w konsekwencji na możliwość przeprowadzenia oceny. Przedstawione wyniki wskazują na praktyczne ograniczenia metody wynikające z warunków środowiskowych w zakresie pogłosowości pomieszczenia. W artykule zaproponowano relatywnie prostą metodę pozwalającą na istotną poprawę parametrów pola akustycznego w stopniu wystarczającym do realizacji pomiarów.

EN

As part of the described tests, measurements of the acoustic insulation of a wall fragment were carried out in situ, in a room whose reverberation time in the area of the tested sample was modified by the use of a material absorbing the acoustic wave and was 1,09 or 1,71 s. The measurements carried out showed a significant impact of changes in room reverberation parameters on the standard indicators of the field assessment and, consequently, on the possibility of carrying out the assessment. The results presented indicate the practical limitations of the method resulting from environmental conditions in terms of room reverberation. The article proposes a relatively simple method that allows for a significant improvement in the parameters of the acoustic field to a degree sufficient to carry out measurements.

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Detrital zircon U-Pb geochronology of a metasomatic calc-silicate in the Tsäkkok Lens, Scandinavian Caledonides

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Barnes C. J. , Majka J. , Bukała M. , Nääs E. , Rousku S.

Geology, Geophysics and Environment

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2021

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tom Vol. 47, no. 1

21--31

EN

The Tsäkkok Lens of the Seve Nappe Complex in the Scandinavian Caledonides comprises eclogite bodies hosted within metasedimentary rocks. These rocks are thought to be derived from the outermost margin of Baltica along the periphery of the Iapetus Ocean, but detrital records from the sedimentary rocks are lacking. Many metasedimentary outcrops within the lens expose both well-foliated metapelitic rocks and massive calc-silicates. The contacts between these two lithologies are irregular and are observed to trend at all angles to the high-pressure foliation in the metapelites. Where folding is present in the metapelites, the calc-silicate rocks are also locally folded. These relationships suggest metasomatism of the metapelites during the Caledonian orogenesis. Zircon U-Pb geochronology was conducted on sixty-one zircon grains from a calc-silicate sample to investigate if they recorded the metasomatic event and to assess the detrital zircon populations. Zircon grains predominantly show oscillatory zoning, sometimes with thin, homogeneous rims that have embayed contacts with the oscillatory-zoned cores. The zircon cores yielded prominent early Stenian, Calymmian, and Statherian populations with a subordinate number of Tonian grains. The zircon rims exhibit dissolution-reprecipitation of the cores or new growth and provide ages that span similar time frames, indicating overprinting of successive tectonic events. Altogether, the zircon record of the calc-silicate suggests that the Tsäkkok Lens may be correlated to Neoproterozoic basins that are preserved in allochthonous positions within the northern extents of the Caledonian Orogen.