Applied sciences

Archives of Acoustics

Content

Archives of Acoustics | 2023 | vol. 48 | No 2

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Abstract

Reverberation time (RT) is an important indicator of room acoustics, however, most studies focus on the mid-high frequency RT, and less on the low-frequency RT. In this paper, a hybrid approach based on geometric and wave methods was proposed to build a more accurate and wide frequency-band room acoustic impulse response. This hybrid method utilized the finite-difference time-domain (FDTD) method modeling at low frequencies and the Odeon simulation at mid-high frequencies, which was investigated in a university classroom. The influence of the low-frequency RT on speech intelligibility was explored. For the low-frequency part, different impedance boundary conditions were employed and the effectiveness of the hybrid method has also been verified. From the results of objective acoustical parameters and subjective listening experiments, the smaller the low-frequency RT was, the higher the Chinese speech intelligibility score was. The syllables, consonants, vowels, and the syllable order also had significant effects on the intelligibility score.
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Authors and Affiliations

Wuqiong Huang
1 2
Jianxin Peng
1
Tinghui Xie
3

  1. School of Physics and Optoelectronics, South China University of Technology, Guangzhou, China
  2. State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou, China
  3. School of Architecture and Art, Shijiazhuang Tiedao University, Shijiazhuang, China
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Abstract

Condition monitoring in a centrifugal pump is a significant field of study in industry. The acoustic method offers a robust approach to detect cavitations in different pumps. As a result, an acoustic-based technique is used in this experiment to predict cavitation. By using an acoustic technique, detailed information on outcomes can be obtained for cavitation detection under a variety of conditions. In addition, various features are used in this work to analyze signals in the time domain using the acoustic technique. A signal in the frequency domain is also investigated using the fast Fourier method. This method has shown to be an effective tool for predicting future events. In addition, this experimental investigation attempts to establish a good correlation between noise characteristics and cavitation detection in a pump by using an acoustic approach. Likewise, it aims to find a good method for estimating cavitation levels in a pump based on comparing and evaluating different systems.
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Authors and Affiliations

Ahmed Ramadhan Al-Obaidi
1
ORCID: ORCID

  1. Faculty of Engineering, Department of Mechanical Engineering, Mustansiriyah University, Baghdad, Iraq
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Abstract

In order to investigate the effect of the surface shape on the performance of perforated panels, three non-flat shapes were considered for perforated panel with their absorption performance compared with the usual shape of the (flat) perforated panel. In order to simulate the absorption coefficient of a non-flat perforated panel, the finite element method was implemented by the COMSOL 5.3a software in the frequency domain. Numerical simulation results revealed that all the shapes defined in this paper improve the absorption coefficient at the mid and high frequencies. A and B shapes had a higher performance at frequencies above 800 Hz compared to the flat shape. Also, shape C had a relative superiority at all frequencies (1–2000 Hz) compared to the reference shape; this superiority is completely clear at frequencies above 800 Hz. The maximum absorption coefficient occurred within the 400–750 Hz range. After determining the best shape in terms of absorption coefficient (shape C), a perforated panel of 10 m2 using fiberglass fibers and desired structural properties was built, and then it was also subjected to a statistical absorption coefficient test in the reverberation chamber according to the standard. The results of the statistical absorption coefficient measurement showed that the highest absorption coefficient was 0.77 at the frequency of 160 Hz. Also, to compare the experimental and numerical results, these conditions were implemented in a numerical environment and the statistical absorption coefficient was calculated according to the existing relationships. A comparison of the numerical and laboratory results revealed acceptable agreement for these two methods in most frequency spectra, where the numerical method was able to predict this quantity with good accuracy.
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Authors and Affiliations

Zahra Hashemi
1
Ali Fahim
2
Mohammad Reza Monazzam
3

  1. Behbahan Faculty of Medical Sciences, Behbahan, Iran
  2. School of Engineering Science, College of Engineering, University of Tehran, Tehran, Iran
  3. School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Abstract

The acoustic effect of windows installed in a prefabricated wood frame façade was considered. Windows inserted into a lightweight wall modify its structural scheme. The research aimed to investigate the possible interaction of the façade’s main components and their actual contribution to the total sound insulation. The principal research question involved the prediction of the acoustic performance of the complete prefabricated panel from the performance of its basic elements, an opaque part and windows. As the frequency-dependent characteristics of the elements differ substantially, the use of single number values for prediction and accuracy was of particular interest. The study is based on laboratory measurements. Initially, two full-scale samples of an opaque wall and four windows were tested separately. Then, several variants of the façade consisting of various combinations of these elements were examined. The results of measurements were juxtaposed and compared with calculated values. The frequency-dependent experimental results were fairly consistent with calculations. The estimations based on single number quantities were also in good agreement with measurements. Thus, it may be concluded that the façade elements did not interact significantly, and the single number calculations give reliable results that can be used in practice.
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Authors and Affiliations

Jacek Nurzyński
1
ORCID: ORCID

  1. Building Research Institute, Warsaw, Poland
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Abstract

A diagnostic technique based on independent component analysis (ICA), fast Fourier transform (FFT), and support vector machine (SVM) is suggested for effectively extracting signal features in infrasound signal monitoring. Firstly, ICA is proposed to separate the source signals of mixed infrasound sources. Secondly, FFT is used to obtain the feature vectors of infrasound signals. Finally, SVM is used to classify the extracted feature vectors. The approach integrates the advantages of ICA in signal separation and FFT to extract the feature vectors. An experiment is conducted to verify the benefits of the proposed approach. The experiment results demonstrate that the classification accuracy is above 98.52% and the run time is only 2.1 seconds. Therefore, the proposed strategy is beneficial in enhancing geophysical monitoring performance.
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Authors and Affiliations

Quanbo Lu
1
ORCID: ORCID
Meng Wang
1
Mei Li
1

  1. School of Information Engineering, China University of Geosciences, Beijing, China
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Abstract

The power injection method (PIM) is an experimental method used to identify the statistical energy analysis (SEA) parameters (called loss factors – LFs) of a vibroacoustic system. By definition, LFs are positive real numbers. However, it is not uncommon to obtain negative LFs during experiments, which is considered a measurement error. To date, a recently proposed method, called Monte Carlo filtering (MCF), of correcting negative coupling loss factors (CLFs) has been validated for systems that meet SEA assumptions. In this article, MCF was validated for point connections and in conditions where SEA assumptions are not met (systems with low modal overlap, non-conservative junctions, strong coupling). The effect of removing MCF bias on the results was also examined. During the experiments, it was observed that the bias is inversely proportional to the damping loss factor of the examined subsystems. The obtained results confirm that the PIM, combined with MCF, allows to determine non-negative SEA parameters in all considered cases.
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Authors and Affiliations

Paweł Nieradka
1 2
Andrzej Dobrucki
1

  1. Wrocław University of Science and Technology, Department of Acoustics, Multimedia and Signal Processing, Wroclaw, Poland
  2. KFB Acoustics, Acoustic Research and Innovation Center, Domasław, Poland
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Abstract

The purpose of this paper is to present the results of the pilot experiments demonstrating proof of concept of three-dimensional strain elastography, based on freehand ultrasound for the assessment of strain induced by endogenous motion. The technique was tested by inducing pulsatility in an agar-based tissue mimicking phantom with inclusions having different stiffness and scanning the 1D array with an electromagnetic position sensor. The proof of concept is explored with a defined physical phantom and the adopted algorithm for strain analysis. The agar-based phantom was manufactured with two cylindrical inclusions having different stiffness (7 kPa and 75 kPa in comparison to the background 25 kPa) and scattering properties. The internal strain in the phantom was introduced by mimicking a pulsating artery. The agar mixture displacements were estimated by using the GLUE algorithm. The 3D isosurfaces of inclusion from rendered volumes obtained from the B-mode image set and strain elastograms were reconstructed and superimposed for a quantitative comparison. The correspondence between the B-mode image-based inclusion volume and the strain elastography-based volume was good (the Jaccard similarity coefficient in the range 0.64–0.74). The obtained results confirm the 3D freehand endogenous motion-based elastography as a feasible technique. The visualization of the inclusions was successful. However, quantitative measurements showed that the accuracy of the method in volumetric measurements is limited.
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Authors and Affiliations

Andrius Sakalauskas
1
Rytis Jurkonis
2
Arūnas Lukoševičius
2

  1. TELEMED, Ultrasound Medical Systems, Vilnius, Lithuania
  2. Biomedical Engineering Institute, Kaunas University of Technology, Kaunas, Lithuania
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Abstract

The dependence of piezoelectric wave impedance on the rotation speed is investigated theoretically and numerically. The Coriolis force due to rotation is introduced into the piezoelectric motion equations, which is solved by the harmonic plane wave solution. It is shown that the wave impedance variations of longitudinal and transverse waves due to rotation are clearly different. The longitudinal wave impedance continuously increases with a small rotation ratio and one transverse wave impedance is almost irrespective of a rotation ratio. In contrast, the rotation applies a big impact on the other transversal wave impedances in the piezoelectric crystal which decreases monotonically with the rotation speed. Such characteristics are significant in piezoelectric transducers and sensors.
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Authors and Affiliations

Xiaoguang Yuan
1
Chaoyu Hao
1
Quan Jiang
1

  1. School of Transportation and Civil Engineering, Nantong University, Nantong, China
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Abstract

In detecting cluster targets in ports or near-shore waters, the echo amplitude is seriously disturbed by interface reverberation, which leads to the distortion of the traditional target intensity characteristics, and the appearance of multiple targets in the same or adjacent beam leads to fuzzy feature recognition. Studying and extracting spatial distribution scale and motion features that reflect the information on cluster targets physics can improve the representation accuracy of cluster target characteristics. Based on the highlight model of target acoustic scattering, the target azimuth tendency is accurately estimated by the splitting beam method to fit the spatial geometric scale formed by multiple highlights. The instantaneous frequencies of highlights are extracted from the time-frequency domain, the Doppler shift of the highlights is calculated, and the motion state of the highlights is estimated. Based on the above processing method, target highlights’ orientation, spatial scale and motion characteristics are fused, and the multiple moving highlights of typical formation distribution in the same beam are accurately identified. The features are applied to processing acoustic scattering data of multiple moving unmanned underwater vehicles (UUVs) on a lake. The results show that multiple small moving underwater targets can be effectively recognized according to the highlight scattering characteristics.
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Authors and Affiliations

Yang Yang
1
ORCID: ORCID
Jun Fan
1
Bin Wang
1
ORCID: ORCID

  1. Key Laboratory of Marine Intelligent Equipment and System of the Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
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Abstract

The presented review discusses recent research on human echolocation by blind and sighted subjects, aiming to classify and evaluate the methodologies most commonly used when testing active echolocation methods. Most of the reviewed studies compared small groups of both blind and sighted volunteers, although one in four studies used sighted testers only. The most common trial procedure was for volunteers to detect or localize static obstacles, e.g., discs, boards, or walls at distances ranging from a few centimeters to several meters. Other tasks also included comparing or categorizing objects. Few studies utilized walking in real or virtual environments. Most trials were conducted in natural acoustic conditions, as subjects are marginally less likely to correctly echolocate in anechoic or acoustically dampened rooms. Aside from live echolocation tests, other methodologies included the use of binaural recordings, artificial echoes or rendered virtual audio. The sounds most frequently used in the tests were natural sounds such as the palatal mouth click and finger snapping. Several studies have focused on the use of artificially generated sounds, such as noise or synthetic clicks. A promising conclusion from all the reviewed studies is that both blind and sighted persons can efficiently learn echolocation.
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Authors and Affiliations

Michał Bujacz
1
Bartłomiej Sztyler
1
Natalia Wileńska
1
Karolina Czajkowska
1
Paweł Strumiłło
1

  1. Institute of Electronics, Lodz University of Technology, Łódz, Poland
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Abstract

The Environmental Noise Directive (END), published in 2002, was transposed into Romanian local law in 2005, and it was the starting point for the first urban noise mapping exercises, initially conducted in nine Romanian cities. This paper presents the main evolutionary aspects of the noise assessment process, the development of strategic noise maps, and action plans, dealing with both the legislative side and the practical approach and results obtained. The study considers the specific regulations established by the European Commission regarding environmental noise assessment and deals with the global context at the country level, in which they have been implemented and applied.
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Authors and Affiliations

Diana Ioana Popescu
1

  1. Technical University of Cluj-Napoca, Cluj-Napoca, Romania
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Abstract

Amplitude modulated noise from a single wind turbine is considered. The time-varying modulation depth D_m and the short time-average sound level L_Aeq,τ (with τ = 20 s) are measured at the reference distance d_*. Due to amplitude modulation, a penalty has to be added to L_Aeq,τ. The paper shows how to calculate the corrected long-term time-average sound level L ̂_AeqT (with T >> 20 s), which accounts for amplitude modulation, at any distance d ≠ d_* from the wind turbine. The proposed methodology needs to be tested by research
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Authors and Affiliations

Rufin Makarewicz
1
Maciej Buszkiewicz
1

  1. Faculty of Physics, Adam Mickiewicz University, Poznan, Poland

Instructions for authors

Author Guidelines
• Manuscripts intended for publication in Archives of Acoustics should be submitted in pdf format by an on-line procedure.
• Manuscript should be original, and should not be submitted either previously or simultaneously elsewhere, neither in whole, nor in part.
• Submitted papers must be written in good English and proofread by a native speaker.
• Basically, the papers should not exceed 40 000 typographic signs.
• Postal addresses, affiliations and email addresses for each author are required.
• Detailed information see Article Requirements.
• Manuscript should be accompanied by a cover letter containing the information:
o why the paper is submitted to ARCHIVES OF ACOUSTICS,
o suggestion on the field of acoustics related to the topic of the submitted paper,
o the statement that the manuscript is original, the submission has not been previously published, nor was sent to another journal for consideration,
o 3–5 names of suggested reviewers together with their affiliations, full postal and e-mail addresses; at least 3 suggested reviewers should be affiliated with other scientific institutions than the affiliations of the authors,
o author’s suggestion to classification of the paper as the research paper, review paper or technical note.

Article Requirements
1. At submission time only a PDF file is required. After acceptance, authors must submit all source material (see information about Figures). Authors can use their preferred manuscript-preparation software. The journal itself is produced in LaTeX, so accepted articles will be converted to LaTeX at production time.
2. The title of the paper should be as short as possible.
3. Full names and surnames should be given.
4. The full postal address of each affiliation, including the country name should be provided. Affiliations should contain the full postal address, as well as an e-mail address of one author designated as corresponding author.
5. The text should be preceded by a concise abstract (less than 200 words).
6. Keywords should be given.
7. The formulae to be numbered are those referred to in the paper, as well as the final formulae.
8. All notations should be written very distinctly.
9. References in the text (author(s) and year of publication) are to be cited between parentheses.
Items appearing in the reference list should be complete, including surname and the initials of the first name of the author, the full title of the paper/book in English followed by the information on the original paper language. In case of a book, the publisher's name, the place and year of publication should be given. In case of a periodical, the full title of the periodical, consecutive volume number, current issue number, pages, and year of publication should be given. All references in the bibliography should be cited in the text, and arranged in alphabetical order by authors' last name.
For more information on references see http://acoustics.ippt.gov.pl/public/Instructions.pdf.
10. Figures must be of publication quality. Each figure should be saved in separate file and captioned and numbered so that it can float. After acceptance, Authors will need to submit the original source files for all photos, diagrams and graphs in manuscript.
For diagrams and graphs vector EPS or vector PDF files are the most useful. Make sure that what you're saving is vector graphics and not a bitmap. Please also include the original data for any plots. This is particularly important if you are unable to save Excel-generated plots in vector format. Saving them as bitmaps is not useful; please send the Excel (.xls) spreadsheets instead.
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