Objective: To verify the levels of sound pressure emitted by non-certified children's toys.
Methods: Cross-sectional study of sound toys available at popular retail stores of the so-called informal sector. Electronic, mechanical, and musical toys were analyzed. The measurement of each product was carried out by an acoustic engineer in an acoustically isolated booth, by a decibel meter. To obtain the sound parameters of intensity and frequency, the toys were set to produce sounds at a distance of 10 and 50cm from the researcher's ear. The intensity of sound pressure [dB(A)] and the frequency in hertz (Hz) were measured.
Results: 48 toys were evaluated. The mean sound pressure 10cm from the ear was 102±10 dB(A), and at 50cm, 94±8 dB(A), with p<0.05. The level of sound pressure emitted by the majority of toys was above 85dB(A). The frequency ranged from 413 to 6,635Hz, with 56.3% of toys emitting frequency higher than 2,000Hz.
Conclusions: The majority of toys assessed in this research emitted a high level of sound pressure.
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http://dx.doi.org/10.1590/s0103-05822013000200013 | DOI Listing |
J Acoust Soc Am
January 2025
Hangzhou Applied Acoustics Research Institute, Hangzhou, Zhejiang 311400, China.
To measure the electroacoustic parameters of transducers in the continuous sound field in a limited water area, a reciprocity calibration method of hydrophones using a spatial sampling average method in a non-anechoic tank was developed. The sound propagation in the non-anechoic tank under the impedance boundary condition, with a sound source producing continuous sound, is introduced based on the Helmholtz equation and Green's function. The reciprocity constant is given using the spatial sampling average sound pressure, and the three-transducer reciprocity calibration procedure was established.
View Article and Find Full Text PDFJ Chem Eng Data
January 2025
LATA2M, Laboratoire de Thermodynamique Appliquée et Modélisation Moléculaire, University of Tlemcen, Post Office Box 119, Tlemcen 13000, Algeria.
The density (ρ), speed of sound (), and refractive index ( ) of ,-dimethylacetamide (DMA) with 1-butanol, 1-pentanol, furfural (FFL), or furfuryl alcohol (FA) as a function of composition and at = 293.15 to 323.15 K with an interval of 10 K and atmospheric pressure were measured.
View Article and Find Full Text PDFInt J Thermophys
January 2024
Applied Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, CO 80305, USA.
Sound speed data measured using a dual-path pulse-echo instrument are reported for pure -1,2-dichloroethene (R-1130(E)) and an azeotropic blend of -1,1,1,4,4,4-hexafluorobutene (R-1336mzz(Z)) and R-1130(E) with a composition of 74.8 mass % R-1336mzz(Z) with the balance being R-1130(E). The azeotropic blend of R-1336mzz(Z)/1130(E) is classified as R-514A in ANSI/ASHRAE standard 34.
View Article and Find Full Text PDFJ Assoc Res Otolaryngol
January 2025
Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, 3010, Freiburgstrasse, Bern, Switzerland.
Purpose: There are challenges in understanding the biomechanics of the human middle ear, and established methods for studying this system show significant limitations. In this study, we evaluate a novel dynamic imaging technique based on synchrotron X-ray microtomography designed to assess the biomechanical properties of the human middle ear by comparing it to laser-Doppler vibrometry (LDV).
Methods: We examined three fresh-frozen temporal bones (TB), two donated by white males and one by a Black female, using dynamic synchrotron-based X-ray microtomography for 256 and 512 Hz, stimulated at 110 dB and 120 dB sound pressure level (SPL).
J Acoust Soc Am
January 2025
Acoustic Technology, Department of Electrical & Photonics Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
Characterising acoustic fields in rooms is challenging due to the complexity of data acquisition. Sound field reconstruction methods aim at predicting the acoustic quantities at positions where no data are available, incorporating generalisable physical priors of the sound in a room. This study introduces a model that exploits the general time structure of the room impulse response, where a wave-based expansion addresses the direct sound and early reflections, localising their apparent origin, and kernel methods are applied to the late part.
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