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Wyświetlanie 1-15 z 48
Tytuł:
Systems modifying the acoustic properties of room furnishings
Autorzy:
Szeląg, Agata
Baruch-Mazur, Katarzyna
Brawata, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/2146662.pdf
Data publikacji:
2022
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
acoustic adaptation
sound absorbing elements
room acoustic parameters
adaptacja akustyczna
elementy dźwiękochłonne
parametry akustyczne wnętrz
Opis:
The article presents an idea how to increase the room acoustic absorption without significantly interfering with its appearance and architectural character. Based on scale model tests, analytical calculations and computer simulations, it has been shown that a noticeable reduction of room reverberation time and improvement of speech transmission index can be achieved by installing additional absorbing systems on selected furniture surfaces. By selecting the appropriate design and location of such systems, the functionality and appearance of the modified furniture can be maintained.
Źródło:
Vibrations in Physical Systems; 2022, 33, 1; art. no. 2022102
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Acoustic Properties of Viscosity Standards
Autorzy:
Kazys, R.
Voleisis, A.
Sliteris, R.
Powiązania:
https://bibliotekanauki.pl/articles/176493.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
viscosity standard
longitudinal and shear waves
ultrasound velocity
Opis:
Longitudinal and shear ultrasonic wave velocities were measured versus temperature in the viscosity standards of Paragon S8000S, N30000S and Cannon N2700000. The measurements were performed by the through-transmission method at the frequency of 2 MHz. Ultrasonic pulses were sent via polymethyl methacrylate (PMMA) waveguides between the tips of which a small amount of the particular standard liquid was placed. The velocities of longitudinal and shear waves were determined to depend on the viscosity of the liquid and increase with the viscosity.
Źródło:
Archives of Acoustics; 2016, 41, 1; 55-58
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Sonication on Acoustic Properties of Biogenic Ferroparticle Suspension
Autorzy:
Józefczak, A.
Hornowski, T.
Król, A.
Molčan, M.
Leszczyński, B.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/176978.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
magnetosomes
sonication
ultrasonic properties
Opis:
Superparamagnetic iron oxide nanoparticles (SPION) synthesised chemically usually need the modification of the particle surface. Other natural sources of magnetic particles are various magnetotactic bacteria. Magnetosomes isolated from magnetotactic bacteria are organelles consisting of magnetite (Fe3O4) or greigite (Fe3S4) crystals enclosed by a biological membrane. Magnetotactic bacteria produce their magnetic particles in chains. The process of isolation of magnetosome chains from the body of bacteria consists of a series of cycles of centrifugation and magnetic decantation. Using a high-energy ultrasound it is possible to break the magnetosome chains into individual nanoparticles – magnetosomes. This study presents the effect of sonication of magnetosome suspension on their acoustic properties, that is speed and attenuation of the sound. Acoustic propagation parameters are measured using ultrasonic spectroscopy based on FFT spectral analysis of the received pulses. The speed and attenuation of ultrasonic waves in magnetosome suspensions are analysed as a function of frequency, temperature, magnetic field intensity, and the angle between the direction of the wave and the direction of the field.
Źródło:
Archives of Acoustics; 2016, 41, 1; 161-168
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Acoustic Properties of a Metamaterial with a Multi-Ring Structure
Autorzy:
Szczepański, Grzegorz
Podleśna, Marlena
Morzyński, Leszek
Włudarczyk, Anna
Powiązania:
https://bibliotekanauki.pl/articles/31339790.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
acoustic metamaterials
numerical research
experimental research
finite element method
multiring structures
Opis:
In this article, the authors present the geometry and measurements of the properties of an acoustic metamaterial with a structure composed of multiple concentric rings. CAD models of the structure were developed and subsequently used in numerical studies, which included the study of resonant frequencies using the Lanczos method and an analysis of sound pressure level distribution under plane wave excitation using the finite element method. Subsequently, experimental tests were carried out on models with the same geometry produced with three different materials (PLA, PET-G, and FLEX) using a fused deposition modeling 3D printing technique. These tests included: determining insertion loss for a single model based on tests using the measurement window of a reverberation chamber and determining transmission loss through tests in a semi-anechoic chamber. Sound wave resonance was obtained for frequencies ranging from 1700 to 6000 Hz. Notably, the experimental studies were carried out for the same structure for which numerical tests were conducted. The physical models of a metamaterial were manufactured using three different readily available 3D printing materials. The results of laboratory tests confirm that the created acoustic metamaterial consisting of multi-ring structures reduces noise in medium and high frequencies.
Źródło:
Archives of Acoustics; 2023, 48, 4; 497-507
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selection of Wood Based on Acoustic Properties for the Solid Body of Electric Guitar
Autorzy:
Zorič, Anton
Kaljun, Jasmin
Žveplan, Ervin
Straže, Aleš
Powiązania:
https://bibliotekanauki.pl/articles/177428.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
wood
acoustic properties
mechanical anisotropy
electric guitar
Opis:
For the purpose of making of a solid body of an electric guitar the acoustic- and mechanical properties of walnut- (Juglans regia L.) and ash wood (Fraxinus excelsior L.) were researched. The acoustic properties were determined in a flexural vibration response of laboratory conditioned wood elements of 430 × 186 × 42.8 mm used for making of a solid body of an electric guitar. The velocity of shearand compression ultrasonic waves was additionally determined in parallel small oriented samples of 80 × 40 × 40 mm. The research confirmed better mechanical properties of ash wood, that is, the larger modulus of elasticity and shear modules in all anatomical directions and planes. The acoustic quality of ash wood was better only in the basic vibration mode. Walnut was, on the other hand, lighter and more homogenous and had lower acoustic- and mechanical anisotropy. Additionally, reduced damping of walnut at higher vibration modes is assumed to have a positive impact on the vibration response of future modelled and built solid bodies of electric guitars. When choosing walnut wood, better energy transfer is expected at a similar string playing frequency and a structure resonance of the electric guitar.
Źródło:
Archives of Acoustics; 2019, 44, 1; 51-58
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Comparative Analysis of Acoustic Properties of Roman Catholic Churches Using the Index Method
Autorzy:
Kosała, K.
Powiązania:
https://bibliotekanauki.pl/articles/1197544.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.55.-n
43.55.+p
Opis:
Development of the index method for acoustic assessment of Roman Catholic churches is presented in the article. The current version of the global index was developed on the grounds of studies conducted in 8 churches and was based on 4 partial assessment indices: reverberation, music sound, speech intelligibility, and external disturbances. The use of sound strength as another partial index for global assessment is proposed in the article. A new formula of the global index for assessment of the acoustic quality of Roman Catholic churches is proposed. The computational procedure of the global index which uses analytical tools such as singular value decomposition (SVD) and comparative multivariate analysis (CMA) resulted from studies and analyses performed on an index observation matrix that was larger than before. Verification of index assessment was carried out for a sample of 12 Roman Catholic churches.
Źródło:
Acta Physica Polonica A; 2014, 125, 4A; A-99-A-102
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
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
Tytuł:
Anisotropic Elastic and Acoustic Properties of Bulk Graphene Nanoplatelets Consolidated by Spark Plasma Sintering
Autorzy:
Koller, M.
Seiner, H.
Landa, M.
Nieto, A.
Agarwal, A.
Powiązania:
https://bibliotekanauki.pl/articles/1402122.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.35.Cg
81.40.Jj
81.05.ue
81.20.Ev
Opis:
Elastic anisotropy and acoustic attenuation in bulk material consisting of consolidated graphene nanoplatelets are studied. The material was prepared by spark plasma sintering, and exhibits highly anisotropic microstructure with the graphene nanoplatelets oriented perpendicular to the spark plasma sintering compression axis. The complete tensor of elastic constants is obtained using a combination of two ultrasonic methods: the through-transmission method and the resonant ultrasound spectroscopy. It is shown that the examined material exhibits very strong anisotropy both in the elasticity (the Young moduli in directions parallel to the graphene nanoplatelets and perpendicular to them differ by more than 20 times) and in the attenuation, where the dissipative effect of the internal friction in the graphene nanoplatelets combines with strong scattering losses due to the porosity. The results are compared with those obtained for ceramic-matrix/graphene nanoplatelet composites by the same ultrasonic methods.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 670-674
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of High-tin Bronze Composition on Physical, Mechanical, and Acoustic Properties of Gamelan Materials
Autorzy:
Slamet, S.
Suyitno, S.
Kusumaningtyas, I.
Miasa, I. M.
Powiązania:
https://bibliotekanauki.pl/articles/1837824.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tin bronzes
mechanical properties
acoustic properties
gamelan
sand casting
brązy cynowe
właściwości mechaniczne
właściwości akustyczne
odlewanie piaskowe
Opis:
High tin bronze alloy (Cu>17wt.%Sn) is commonly as raw material to fabricate musical instruments. Gamelan musical instruments in Indonesia are produced using tin bronze alloy raw materials. The tin bronze alloy used by each gamelan craftsman has a different tin composition, generally in the range of Cu(20-24) wt.% Sn. This study aims to investigate the effect of microstructure, density, and mechanical properties of Cu(20-24)wt.%Sn against the acoustic properties processed by the sand casting method. The material is melted in a crucible furnace until it reaches a pouring temperature of 1100ºC by the sand casting method. The specimens were subjected to microstructure observations, density and porosity as well as mechanical properties testing including tensile strength, bending strength, hardness, and modulus of elasticity. Mechanical properties data then used to calculate several parameters of acoustic properties including speed of sound (c), impedance (z) and radiation coefficient (R). Processes simulation using Finite Element Analysis (FEA) and Experiment Method Analysis (EMA) were carried out to determine acoustic properties including sound intensity, natural frequency and damping capacity. The experimental result shows that the increase in tin composition in Cu(20-24) wt.% Sn changed the microstructure of coarse grains into dendrite-columned fine grains. Physical properties of density decrease, while porosity increases. Mechanical properties including tensile strength, modulus of elasticity, and bending strength decreased, while the hardness of the alloy increases. The calculation of acoustic parameters such as the speed of sound (c), impedance (z) and radiation coefficient (R) has decreased. Moreover, sound intensity (dB), natural frequency (Hz) and damping capacity also decrease with increasing tin composition. Hence, tin bronze alloy Cu20wt.%Sn is the recommended raw material for the manufacture of gamelan instruments through the sand casting method.
Źródło:
Archives of Foundry Engineering; 2021, 21, 1; 137-145
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of seasonal acoustic properties of sea water in selected waters of the southern Baltic
Autorzy:
Grelowska, G.
Powiązania:
https://bibliotekanauki.pl/articles/259798.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
sound propagation in sea water
acoustic climate of Baltic Sea
Opis:
Climate Research of the globe is a current task, in particular to confirm the general hypothesis of global warming associated with an increase in average temperature. The sea acoustic climate is derived from the concept of climate and refers to the conditions of propagation of acoustic waves in a particular basin. In this paper, the results of systematic measurements of temperature, salinity and velocity distributions of sound in the area of the southern Baltic will be present. The focus will be on the results of extensive measurements carried out „in situ” in particular.
Źródło:
Polish Maritime Research; 2016, 1; 25-30
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the impulse response method in the test of acoustic properties of building materials
Autorzy:
Piechowicz, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/2146655.pdf
Data publikacji:
2021
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
impulse method
sound absorption coefficient
MLS
e-sweep
metoda impulsowa
współczynnik pochłaniania dźwięków
Opis:
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.
Źródło:
Vibrations in Physical Systems; 2021, 32, 2; art. no. 2021201
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental tests of the acoustic properties of sound-absorbing linings and cores of layered baffles
Autorzy:
Kosała, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/2146647.pdf
Data publikacji:
2021
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
sound transmission loss
sound absorption coefficient
insertion loss
baffles
mineral wool
izolacyjność akustyczna od dźwięków powietrznych
współczynnik pochłaniania dźwięku
tłumienie przepustowe
przegrody
wełna mineralna
Opis:
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.
Źródło:
Vibrations in Physical Systems; 2021, 32, 1; art. no. 2021107
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analysis of the acoustic properties of granular materials determined with the use of impedance tube
Autorzy:
Kosała, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/24202011.pdf
Data publikacji:
2022
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
granular materials
sound absorption coefficient
sound transmission loss
materiały ziarniste
współczynnik pochłaniania dźwięków
strata transmisji dźwięku
Opis:
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.
Źródło:
Vibrations in Physical Systems; 2022, 33, 3; art. no. 2022321
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Overshooting Americanisation. Accent Stylisation in Pop Singing – Acoustic Properties of the Bath and Trap Vowels in Focus
Autorzy:
Konert-Panek, Monika
Powiązania:
https://bibliotekanauki.pl/articles/620974.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
overshoot
singing accent
staged performance
stylisation
the BATH- TRAP split
Opis:
The paper addresses the problem of overshoot involved in singing accent stylisation. Selected phonetic features indexed as “American” and “Cockney” are analysed in the singing and speaking styles of a British vocalist, Adele. Overshoot, understood as a greater frequency or an exaggerated quality of a given feature, is characteristic of staged performance (Bell and Gibson 2011; Coupland 2007). PRAAT is used to establish the acoustic properties (F1 and F2) of the BATH and TRAP vowels, as well as the presence or absence of the BATH-TRAP split. The results show that Americanisation regarding the BATH-TRAP split in singing is present and the Americanised vowel tokens are “overshot”, having higher F2 frequency compared with the regular British TRAP vowel.
Źródło:
Research in Language; 2017, 15, 4; 371-384
1731-7533
Pojawia się w:
Research in Language
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cardiac Activity Based on Acoustic Signal Properties
Autorzy:
Czopek, K.
Powiązania:
https://bibliotekanauki.pl/articles/1490378.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.60.-c
43.60.+d
87.19.ug
Opis:
The influence of sleeping conditions on human health and well-being is now fully understood, but still underestimated. Sleep disorders e.g. snoring, wheezing or sleep apnea are widespread among people of all ages, although prevalent amidst the male population, obese people with a high value of BMI, people who suffered a stroke, have hypertension or other heart diseases. Medical support is needed in order to ensure a good night's sleep for patients suffering from sleep disorders. Sleep monitoring is also very important in case of emergencies. This research was aimed at finding a correlation between sleep disorders represented by acoustic signals and heart activity parameters. The measurement of breathing through simultaneously acquired acoustic and ECG signals is used to quantify the respiratory obstruction during sleep. The information collected by synchronized recording of acoustic effects and the ECG signal partly overlaps, giving an opportunity to improve accuracy of measurement. Results indicate that the aspect of sleep analysis can be extended using this method. The information collected by simultaneous recording of acoustic effects and the ECG signal is provided and the results are described.
Źródło:
Acta Physica Polonica A; 2012, 121, 1A; A-042-A-045
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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