bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction and evaluation of the low-frequency noise impact from industrial noise sources
Authors: HANSEN Heiko
Published: October 2024

German legislation requires an assessment of low-frequency noise in addition to the regular noise assessment for industrial plants. The detailed prediction and assessment of low-frequency noise immissions is carried out according to the administrative regulation for noise TA Lärm
and the German standard DIN 45680. However, a standardised procedure for predictions of low-frequency noise does not exist. For this reason, different approaches for the prediction of low-frequency noise immissions have been developed over the last two decades. Typically, the method according
to DIN ISO 9613-2 for sound propagation outside is extended heuristically to the lower frequency range. The predicted low-frequency noise level outside the room is taken as a basis for determining the noise immission level inside the room. The level of knowledge about the quality of sound
propagation modeling of low-frequency noise is still debatable. A forecast method of low-frequency noise components should be on the "safe side" in terms of noise control; however, the scope of the required measures to meet the noise requirements must be comprehensible and proportionate.
We present an overview of the building blocks of a forecasting process and the challenges that arise. The topic is illustrated by a practical example.
On improving sound source localization in the wind tunnel
Authors: PUHLE Christof
Published: October 2024

When traveling in an open-jet wind tunnel, the path of an acoustic wave is affected by the flow causing a shift of source positions in acoustical maps of phased arrays outside the flow. In this paper, we start by comparing several well-known approaches to correct travel times between
microphones and assumed sources, used, for example, by beamforming algorithms in such an environment. The methods under consideration include the original 1D-Amiet/Bahr formulation, a standard 2.5D-planar approach that assumes the constancy of angular frequency and wave-number-vector components
along a plane, and finally, a 3D-ray-tracing method. Common to the former two of these methods is the assumption that the boundary layer of the flow, the so-called shear layer, is infinitely thin and refracts the acoustical ray, whereas, in principle, the latter algorithm allows for an arbitrary
(but sufficiently smooth) vector field modeling the flow. Going through these methods, we discuss travel-time results relative to each other and in terms of differences in source localization using beamforming maps. In particular, we model the flow of an existing wind tunnel and discuss results
of real-world measurements comparing the 2.5D-planar approach with the 3D-ray-tracing method.
Effect of scatterer shape, opening angle and periodicity on sound attenuation by local resonating sonic crystal
Authors: CHALURKAR CHETAN , SINGH SNEHA
Published: October 2024

Noise Control has become critical and demanding task for acoustic engineers due to continuous Technological developments in construction, transportation, and industries. These developments have raised the level of low frequency noise in densely populated areas. Unfortunately, there
cannot be sufficient noise reduction with traditional acoustic materials. However, new research has shown that the manipulation of sound waves and drastic reduction in sound transmission can be possible using periodic structure known as Sonic Crystals (SnC). This study describes the eigenfrequency
analysis to investigate the effect of different shapes, periodicities, and opening angles of scatterers in a Local resonating Sonic Crystal (LRSnC). The Block-Floquet boundary condition is applied to the unit cell of the LRSnC, using the Finite Element Method to study the complex acoustic
wave interactions throughout the structure. An acoustic module has been applied to find the band gap and to simulate transmission loss spectra in COMSOL Multiphysics. Results show that shape, opening angle and periodicity effect the band gap and transmission loss significantly. Based on these
results, it is possible to develop advanced SnC with a wider band gap and higher sound attenuation in the lower sound frequency range by carefully considering these factors.
WIND power noise systematically underestimated in Sweden
Authors: PERSSON Bertil
Published: October 2024

This paper outlines a numerical study of measurement faults in regard to wind power turbines in Sweden. For this purpose, seven (7) reports of noise level from four (4) wind power stations, with between seven (7) and 47 on shore turbines, and between 145 m and 230 m high, were examined.
Parallel studies were performed with analytic methods. Technically the noise level was undervalued by more than five (5) dB(A). The effect of the wind speed at 10 m height, according to the IEC64100-11 regulations, was generally not taken into account. In some cases, only the wind speed at
the turbine hub was regarded. Thereby the correct wind speed at 10 m height was overstated by up to five (5) meters per second. In one case the measurement of wind power noise was measured at wind speed between three (3) and four (4) meters without the wind turbine blades moving at all. In
summary the wind power noise levels were suppressed by about 5 dB(A) for the wind power stations analyzed in Sweden. The study results in a differentiated model as compared to the required rule in IEC64100-11. The projects were carried out between the years 2012 and 2024.
Experimental validity of using a ResNet to predict sound absorption coefficients of finite samples
Authors: ASTE Patrik , BRANDãO Eric , CUENCA Jacques , NOLAN Mélanie , SVENSSON U. Peter , ZEA Elias
Published: October 2024

The validity of using a neural network to predict sound absorption coefficients of finite porous materials is tested with experimental data with a flush-mounted glass wool sample on a baffle. The network is pre-trained and validated with numerical simulations of flushed-mounted finite
absorbers using a Delany-Bazley-Miki model. The experimental setup consists of a 12 x 12 microphone array placed above the absorber and a sound source placed at angles of 0, 40, and 75 degrees with respect to the normal of the sample. The sound absorption coefficients predicted at normal incidence
by the network are compared with the impedance tube method as a reference result.
Simulating noise and vibrations on passenger ships using Statistical Energy Analysis
Authors: BAUDET Adrien , BRANCHEREAU Sylvain , ERRICO Fabrizio
Published: October 2024

Various sources aboard a passenger ship contribute significantly to noise and vibration concerns. Notably, fluctuating pressure loads on the hull can result in elevated noise levels within rooms near the propulsion. Expensive solutions of sound insulation such as floating floors are
employed to reduce these levels. Nowadays, designing these treatments is mainly based on empirical studies. However, the limited availability of the ship, the laborious nature of experiments, and the possibility of solutions being oversized have only increased the method's constraints. Utilizing
calculation methods can save time, reduce additional weight on the ship, and provide more tailored design solutions. A Statistical Energy Analysis (SEA) has been used as deterministic approaches are often not suitable for the frequency range of interest for full-scale structures. The validation
process for the wave-based SEA method involves several steps. Initially, simple models are constructed to establish correlations between local airborne and structure-borne energy transmission using simple acoustic loads, as well as to assess the method's scope of application. Subsequently,
this approach is applied to larger models, such as the aft full part of the ship, enabling the prediction of noise levels and energy transmission paths under real loads.
Exploring sauna impulse responses
Authors: PRAWDA Karolina , MEYER-KAHLEN Nils , SCHLECHT Sebastian
Published: October 2024

Sauna is an important element of Finnish tradition and culture, and its properties and features deserve preservation and archiving. Additionally, extreme temperature and humidity in a sauna comprise a unique environment for researching room acoustics in unusual atmospheric conditions.
In the present study, we publish a dataset of room impulse response (RIR) measurements of a sauna during the process of warming up and throwing water on the stove. We explore several features of the dataset, such as the impact of the temperature and humidity distributions on the time-of-arrival
of reflections, the atmospheric absorption of sound, and spectral coloration of measured RIRs. The results of this research show the influence of environmental factors on RIRs and allow an insight into the distinct room acoustics of a sauna while heating up.
Relevance of noise control for the development of acoustics in 20th century
Authors: SCHEUREN Joachim
Published: October 2024

Driven by progress and requirements of the advancing machine age, Acoustics of the 20th century has run through a tremendous development. Starting from a profound understanding and formulation of its theoretical physical framework by Hermann von Helmholtz and Lord Rayleigh at the end
of the 19th century, Acoustics and its many sub-disciplines developed to an important technical and engineering discipline which, at the beginning of the 21st century, had become a basic design tool for environmental compatibility and comfort features of most technical products and utilities.
In Europe, this development has strongly been driven by urgent requirements of fast after-war reconstruction and growing needs of noise control which enforced particular interactive efforts of research institutes and companies to cope with the challenges of the time. Based on recent widespread
contributions to the history of European Acoustics presented at Forum Acusticum 2023 in Torino, the relevance of noise control for the development of Acoustics in the last century will be highlighted and appreciated. With reference to some typical examples, it will be shown how the disciplines
of engineering acoustics and noise control essentially contributed to renew and strengthen acoustics as an indispensable interdisciplinary field of science and technology.
Associations between acoustic indices and the evaluation of the urban soundscape according to ISO 12913
Authors: HASELHOFF Timo , SCHRöER Kai , SCHRöDER Judith , MOEBUS Susanne
Published: October 2024

The development of high-quality acoustic environments (AE) is crucial for the transformation of cities into sustainable and health-promoting places. In recent years, the soundscape approach (ISO 12913) has gained attention for quantifying the AE using a standardised questionnaire for
soundwalk participants. This way, several qualities of the AE can be analysed. However, soundwalks are costly and limited to a select number of sites. To scale up the assessment of the urban AE, the use of acoustic indices, which could reflect different qualities of a soundscape, represents
a promising approach. Therefore, we present an analyses of the association between acoustic indices and affective soundscape qualities. We use soundscape data from the Be-MoVe project in Essen, Germany. In total, 35 soundwalks with 143 participations were conducted and data were collected
from 858 questionnaires for 22 listening stations, each with a three-minute audio recording. These recordings are used to calculate ecoacoustic indices and complex network measures based on frequency correlation matrices, as these have shown promising results in previous studies. We present
results from descriptive statistics as well as multi-level regression analyses modelling the relationship between self-rated affective qualities of AE and acoustic indices, taking into account spatial variability between different urban locations.
Recent investigations using an artificial player for brass instruments
Authors: FRéOUR Vincent , FUJITA Kazuhiro , SHOJI Tetsuro , MASUDA Hideyuki , ARIMOTO Keita , COCHELIN Bruno , SABATIER Laurent , VERGEZ Christophe
Published: October 2024

Artificial players show great interest for scientific studies on musical instruments: they allow sound production mechanisms to be reproduced, while making it possible to monitor several variables of the system that are usually difficult to measure on human players. In brass instruments,
where the reed consists of the lips of the players, several systems have been developed over the years in research laboratories. In order to build artificial lips, one crucial element of the system, different solutions were proposed, such as latex tubes filled with water or rubber sheets.
Although very realistic sounds can be obtained with some systems, one difficulty remains to build an apparatus which is relatively easy to control, stable, and repeatable. In this presentation, we will introduce the latest version of the brass artificial player developed in Yamaha and recently
at LMA, which is based on a quite efficient, yet relatively simple, solution for the lips. The system then provides ease of use, stability and repeatability, while generating very realistic sounds. We will present some studies conducted with this new apparatus, and also demonstrate a portable
version of it, that can trigger some ideas for other applications than research.
The impact of confounding factors on moderating short-term responses to noise: A follow-up study conducted at a hospital near Tan Son Nhat Airport
Authors: TRIEU Bach Lien , NGUYEN Tran Thi Hong Nhung , NGUYEN Thu Lan , MORINAGA Makoto , HIRAGURI Yasuhiro , MORIHARA Takashi , YANO Takashi , SASAZAWA Yosiaki , TRAN Quoc Viet , BUI Duc Thanh , TRAN Ha Hieu , NGUYEN Thi Ngoc Dung , DO Pham Nguyet Thanh
Published: October 2024

This study explores the intriguing phenomenon of positive participant responses amidst sustained high noise levels in a follow-up survey conducted in the previous year (2023) at Military Hospital 175. Building upon the initial 2022 survey, our investigation reveals a noteworthy continuity
of positive responses from participants, despite the persistent influence of high noise levels on both staff and patients. This study, expanding its focus to include road traffic noise surrounding the hospital, highlights the resilience demonstrated by individuals within the hospital environment.
The results suggest a complex interplay between perception and adaptation to noise, emphasizing the need for a nuanced understanding of the psychological and physiological responses to sustained high noise levels. This study contributes valuable insights for future interventions and strategies
aimed at promoting well-being in healthcare settings with persistent noise challenges.
A cloud-based simulation framework for high-fidelity room impulse response dataset generation: case study, validation and computational performance
Authors: HAFSTEINSSON Haukur , PIND Finnur , GUðJóNSSON Steinar , SAMPEDRO LLOPIS Hermes , ÁSGEIRSSON Matthías
Published: October 2024

Increased cost-effective computational resources in the cloud in combination with state-of-the-art simulation algorithms has opened doors for generating large quantities of simulated high-fidelity room impulse responses. Such datasets can, e.g., be used for training machine learning
based audio signal processing algorithms such as speech enhancement or dereverberation, as well as for carrying out virtual prototyping of audio devices in different acoustic conditions. The authors have previously presented a cloud-based simulation engine that is well suited for such large-scale
dataset generation tasks. The simulation engine leverages a hybrid wave/geometrical solver, in combination with various geometry pre-processing technology and spatial audio post-processing technology. In this paper, we present a dataset generation case study using this simulation engine, as
well as a novel validation study into certain aspects of the spatial audio post-processing. Finally, we present an analysis into computational performance when leveraging multi-node computational architectures to run extremely large wave-based simulations using the simulation framework. To
the best of our knowledge, this is the first time a multi-node wave-based acoustics solver presented, enabling wave-based simulations with billions of degrees of freedom.
Measuring pro-environmental (noise) behavior- Preliminary results of a large online survey across countries
Authors: FIEBIG André , MOSHONA Cleopatra Christina , CZUKA Martin , CONTER Marco , CHUDALLA Michael , STRIGARI Fabio
Published: October 2024

Studies on noise effects offer comprehensive insights into the connections between noise exposure and human responses, taking into account various moderators. Nevertheless, the predominant focus tends to lie on the perspective of those exposed and affected. Aspects of individual, noise-conscious
behavior, so as not to disturb others, have received notably less attention. Based on the concept of noise-conscious behaviors, which recognizes the avoidance of noise as a crucial social and personal responsibility, including the willingness to permanently adapt one's own conduct, an online
survey was carried out in Germany, Austria and Switzerland with the participation of over 400 individuals. The analysis of the survey focuses on the topic of noise-conscious behavior and the factors promoting or inhibiting specific noise-sensitive behavior, especially in the context of vehicle
driving. The paper presents initial findings and discusses the significance of these observations for promoting sustainable noise reduction. The work conducted is part of the research project "Verhaltensbezogene Lärmminderungsmaßnahmen" - VELMA (FE 69.0013/2022), which
is funded by the German Federal Ministry for Digital and Transport, represented by the German Federal Highway Research Institute. The responsibility for the content lies solely with the authors.
Total harmonic distortion estimation in piezoelectric micro-electro-mechanical-system loudspeakers via a lumped elements approach
Authors: GAZZOLA Chiara , CORIGLIANO Alberto , ZEGA Valentina
Published: October 2024

In the context of the increasing trend towards miniaturization required by new wireless audio devices, piezoelectric micro-electro-mechanical-system (MEMS) loudspeakers are getting extensive attention. Finite Element Methods (FEM) and Lumped Element Methods (LEM) models able to accurately
predict their linear response have been recently proposed in the literature. However, a nonlinear model able to predict the Total Harmonic Distortion (THD) of theses types of devices is to date not available. In this paper we present a FEM- assisted lumped-parameters equivalent circuit accounting
for piezoelectric hysteresis which demonstrates good agreement with experimental THD results carried out on piezoelectric MEMS loudspeakers prototypes fabricated by STMicroelectronics. The nonlinear electro-mechanical domain is simulated through a Reduced Order Model (ROM) which considers
as basis function the pre-stressed undamped actuated mode of the device computed via FEM, to simulate loudspeaker diaphragms of arbitrarily complex geometry. The parameters of the acoustical circuit are instead derived through analytical formulas.
Annoyance assessment of the combined effect of railway noise and vibration including physiological measurements
Authors: JAGLA Jan , HAESE Gwénaëlle , ROPARS Pierre , GUIGOU CARTER Catherine , MAILLARD Julien , PICARD Nicolas , JACOB Ségolène
Published: October 2024

The prediction of annoyance due to railway transportation in residential areas is crucial to correctly dimension noise and vibration reduction solutions. In situ annoyance assessment for multiple exposition scenarios requires to convince many residents to take annoyance tests combined
with noise and vibration measurements inside their homes. Such approach is not adapted to large-scale experiments. Therefore, the VibAcouPhysio project aims at studying annoyance due to railway noise and vibration in laboratory conditions. A vibrating platform combined with a high-quality
sound reproduction system has been designed for this project to reproduce the noise and vibrations of a train pass-by. Annoyance is estimated by multiple means including questionnaires, cognitive tasks performance assessment and various physiological measurements. Twenty participants were
exposed to various train pass-by signals as if they were seating at a table inside their housing. The results show a significant correlation between physiological metrics, the annoyance evaluated in the questionnaires and the physical indicators derived from the noise and vibration signals.
The main purpose of the VibAcouPhysio project is to rank various physical indicators describing noise and vibration signals according to their correlation to the perceived or measured annoyance.
Evaluating young people's listening practices: a public health issue
Authors: ROZEC Valérie , PEREZ MENOZ Antoine , BEDHOUCHE Charlotte
Published: October 2024

Listening to music through headphones or earphones has become commonplace with the development of new technologies. If this listening is prolonged over long periods and at high noise levels, it exposes young people to risks to their hearing systems. The WHO (2021) indicates that one
person in four is expected to have hearing problems by 2050, and 1.1 billion young people worldwide could be at risk of hearing loss due to dangerous listening habits. Three French organizations (Le RIF, Bruitparif and CidB) have joined forces, with the support of the regional health agency
of Ile de France, to coordinate their hearing risk prevention campaign and carry out a study ahead of the campaign to find out about listening practices using headphones or earphones, concert attendance and the precautions taken by teenagers to protect themselves from hearing risks. The results,
based on a sample of 2,685 teenagers (secondary school), will provide a snapshot of practices so that prevention messages can be adapted during awareness campaigns.
Flapping dynamics of a flexible membrane attached to the leading edge of a forward-facing step
Authors: LIU Zhiwei
Published: October 2024

An experimental investigation of velocity fields over and wall pressure fluctuations on a forward-facing step (FFS) disturbed by a flexible membrane has been conducted. A two-dimensional flexible membrane of 40mm length and 0.15mm thickness attached to a FFS of 40mm height was tested
with oncoming velocity in the range of 7.3 < U < 12.9 m/s, corresponding to Reynolds numbers of 20391 < ReH < 35312 based on the step height. A high-speed camera was used to reconstruct the configuration of the flapping membrane. The flow field velocity dataset in the horizontal-vertical
plane and the pressure fluctuation on the step surface were measured by planar particle image velocimetry and pressure sensors, respectively. The flexible membrane displayed two distinct modes, viz. a bending mode or flapping mode. In the bending mode, the membrane elevates the shear layer,
thereby delaying the reattachment of separation flow generated by a FFS. In the flapping mode, the membrane periodically generates flapping-induced vortices (FIVs) of different scales with varying Reynolds numbers. The pressure on the FFS also undergoes periodic fluctuations corresponding
to these FIVs.
The impact of active components wear on psychoacoustic parameters of noise in a car cabin
Authors: JóSKA Jakub , PIETRUSIAK Damian , BARAńSKI Filip
Published: October 2024

The automotive industry is undergoing an electromobility revolution. Changing a car's drive unit influences the vibroacoustics of a car's interior. Drive-train noise at low car speeds and in the low-frequency range is no longer dominant. There is no masking effect due to the noise of
the combustion engine, and a passenger paradoxically may perceive the noise of a car as less pleasant. Moreover, existing vibroacoustic requirements have to some extent taken into account the change in the noise of components with the usage time, but there are still areas that require further
research. This paper focuses on the study of electric adjustable seats, power windows and power exterior mirrors in different wear states, to determine the significant psychoacoustics changes of the selected car component's noises. The study is part of extensive research that aims to revise
the current vibroacoustic requirements for new components and to determine how they could be tested and evaluated.
Design of a new low-noise pavement
Authors: ASPURU Itziar , SANZ Roberto , VAZQUEZ Manual , BARRAL Marisol , GARCíA Antonio , SAIZ-RODRíGUEZ Leticia
Published: October 2024

This paper presents the results obtained from the tests carried out on the different asphalt mixes that have been developed as part of the PERSEUS project. This project aims to develop a low-noise pavement in which, in addition to traditional parameters such as texture or absorption,
which have been defined based on aggregate size and void content, the aim has been to improve the acoustic response by introducing rubber as a substitute for part of the aggregate in the recipes. Within the framework of the project, porous mixtures and also stone mastic are being developed
to determine the solution with the best acoustic characteristics and durability. The paper presents the results of acoustic characterization tests carried out (absorption, airflow resistance) in the phase of design of mixtures, as well as those obtained from the mechanical impedance test,
which together with the results of the mechanical tests will conclude which is the ideal mixture to be tested on a stretch of road with real traffic.
An auralisation approach for tyre/road noise
Authors: KROPP Wolfgang , MüLLER Leon , THEYSSEN Jannik
Published: October 2024

Tyre/road noise is one of the main sources of traffic noise. Over the years, different approaches have been made to study the influence of road and tyre design on the noise generation and to reduce the negative impact of rolling noise on health and wellbeing. The study of human perception
of tyre/road noise requires time signals of rolling noise for listening tests. Recorded signals could be used for this purpose, however, this only allows to investigate existing tyres and roads. Alternatively, simulated signals could be used. This paper presents a methodology to rolling noise
signals based on physical modelling of the tyre/road contact. The Chalmers tyre/road interaction model has been extended to allow for calculating sufficiently long time signals in the form of CPX signals and/or pass-by signals. The approach is demonstrated by considering a surface with a contraction
joint. The results indicate that the model might be suitable for listening tests or psychoacoustic evaluation.
Towards an open digital catalogue of sound signatures from the underwater soundscape
Authors: MAISON Timothée , BLAYO Camille , PIHAN Yaëlle , PIHAN-LE BARS Hélène , LAJAUNIE Myriam , CEYRAC Laura
Published: October 2024

Passive acoustic monitoring plays a crucial role to study the underwater soundscape. Identifying the sound signatures of specific marine species and anthropogenic contributions is a key step in assessing the impact of human activities on the acoustic environment. The project COSS (Catalogue
of Sound Signatures) aims to build an open library of sound signatures from the coastal seascape of European waters. In this framework, a data management workflow is developed within FAIR principles from the storage of the metadata, ensuring integrity and traceability of the recorded datasets,
to the analysis and the annotation method, providing interoperability classification of sound signatures. An interactive map provides an overview of the database. Sound events are analyzed using a home-made annotation software. Labeling is based on a tree-structure ontology with respect to
the biological species, human activities and geophony. This labels standardization makes it possible to extract information at several levels of precision. In particular, this library will serve as a learning and testing base for open source AI algorithms for the automatic classification of
signals of anthropogenic origin. A long-term objective is to provide a means of determining the acoustic impact of human activities on the marine environment.
A reservoir computing approach in active noise control for vehicle applications
Authors: MYLONAS Dimitrios , ERSPAMER Alberto , YIAKOPOULOS Christos , ANTONIADIS Ioannis
Published: October 2024

Reservoir Computing (RC) is an alternative approach to Recurrent Neural Networks (RNN) that can avoid some shortcomings of conventional gradient decent-training that are mainly related to high computational complexity and the reduced ability to "learn" long-range dependencies.
In RC the input data are transformed into patterns in a high-dimensional space by an RNN called the "reservoir", which remains unchanged during training. The desired output signal is generated as a linear combination of the neuron's signals from the input-excited reservoir. The linear
part of the RC architecture, which is called the "readout" can be trained with a simple learning algorithm such as linear regression. In this work an RC architecture is proposed for the attenuation of acoustic disturbances encountered in vehicle cabins such as aircrafts and yachts.
At first, a dataset of acoustic pressure measurements from real-world cabins was used to generate the readout and reservoir layers. Subsequent computer simulations demonstrated that the proposed architecture can successfully attenuate such acoustic disturbances. Finally, the performance of
RC in Active Noise Cancellation task was compared with both the linear FxLMS algorithm and a conventional RNN, showing that it has several advantages regarding acoustic pressure reduction combined with relatively low computational complexity.
On the effect of indoor acoustic conditions in performing cognitive tests in primary school
Authors: BATTAGLIARIN Lisa , SPICCIARELLI Gaia , GHELLER Flavia , CAPPELLETTI Francesca , DI BELLA Antonino , PACCAGNELLA Omar , ROMAGNONI Piercarlo , ARFé Barbara
Published: October 2024

The quality of the acoustic environment is essential to foster learning as students learn by listening to the teacher. Prolonged exposure to noise during critical learning periods at school can impair development and have a lifelong effect on academic achievement. This is why the problem
of noise is of concern in learning environments such as schools. Poor acoustic quality leads to increased cognitive effort that is associated with greater difficulty in processing and remembering information in the short and long term. Preliminary results from the administration of neuropsychological
tests under quiet and noise conditions only partially supported the hypothesis that noise negatively impacts children's cognitive performance. In fact, only in one of the two monitored schools the children's performance was affected by the presence of noise during the execution of the tests.
In this paper, new results obtained from the correlation between the acoustic parameters and the children's responses to the cognitive load assessment questionnaire are presented to confirm the validity of the hypotheses.
The role of person-related factors and acoustic parameters on students' perception: a pilot study
Authors: VISENTIN Chiara , POMPEI Chiara , BAMBINI Valentina , PRODI Nicola
Published: October 2024

Classrooms are dynamic spaces where the sound environment not only influences the comprehension of the teacher's message but also shapes the social and emotional atmosphere within the class. This pilot study investigates the sound perception of students within classrooms, considering
both person-related and acoustic objective factors as predictors. Thirty-four students from two grade-four classes of a primary school in Pavia, Italy, participated in this study, completing a questionnaire assessing the perceived pleasantness, arousal and loudness within the classroom. Person-related
factors such as noise sensitivity, working memory, theory of mind, and language skills were also evaluated separately. Sound levels in occupied conditions were monitored and processed using Gaussian Mixture Models to separate teacher speech levels from students' activity. Additionally, acoustic
parameters including reverberation time and clarity were measured in unoccupied conditions. Person-related factors were analysed in relation to subjective evaluations, considering the potential mediating effect of the classroom sound environment. The results of this study will offer insights
into the complex interplay between person-related characteristics and the sound environment, shedding light on factors beyond noise interferences that impact students' subjective perception in educational settings.
Acoustical dissipation in biobased granular packings
Authors: GLé Philippe , NIEDERMEYER Lisa , ZHANG William , CHATEAU Camille , LECOMPTE Thibaut , CHEKAI Tinhinane
Published: October 2024

Biobased building materials have many advantages, including local availability and functional performance in terms of mechanical, acoustic and hygrothermal properties. Besides, the biobased solutions coming from plants that uptake CO2 during their growth, are good opportunities to reach
carbon-neutral building construction. However, mastering their acoustical performance still raises a number of questions directly linked to their microstructure, which is characterised by a high degree of porosity spread over several scales. The work presented here aims to highlight the effect
of the porosity distribution in biobased granular packings on their acoustical performances. Several plant aggregates are considered, such as hemp shiv, sunflower pith or reed as a function of their density and water content. Characterizations are performed in normal incidence and compared
to fluid equivalent modellings based on various assumptions, to analyze the effective contribution of the various types of pores at the aggregate level, and between the aggregates.
Estimation of viscoelastic properties in ribbon-shaped homogeneous waveguides by wavenumber analysis and model reduction
Authors: POUDREL Anne-Sophie , BOCHUD Nicolas , RéBILLAT Marc , ROSI Giuseppe , PEIXINHO Jorge , MARGERIT Pierre
Published: October 2024

Wavenumber based procedures applied to 1D waveguides provide a rigorous framework with an exact signal model that allows for a proper identification of both storage and loss properties independently from the boundary conditions. However, the associated inverse problem is either computationally
intense if using a reference solution (e.g. SAFE) or limited to a specific frequency range that depends on the reduced beam model. We propose here to apply the wavenumber-based estimation of isotropic viscoelastic properties to ribbon-shaped homogeneous waveguides, characterized by a rectangular
section with slender height-to-width aspect ratio. We show theoretically that considering the ribbon as a thick plate by assuming a model reduction in the height dimension, drastically reduces the wave propagation problem (hence its inverse counterpart) while providing a sufficiently good
approximation on the low height-to-wavelength regime. In addition, full-field measurements are performed on an Aluminium and a PVC homogeneous ribbon-shaped waveguide. The experimental dispersive branches (bending and torsion modes) are identified on an ultra-wide frequency range (1 kHz -
1 MHz) using High Resolution Wave Analysis. For both materials, an excellent agreement is observed with the thick plate reduced model, paving the way for wide-band viscoelastic properties identification of ribbon-shaped waveguide.
Monitoring of indoor environmental quality and acoustic comfort in university classrooms
Authors: FISSORE Virginia Isabella , CHIAVASSA Pietro , AYDIN Tugana , BELLATORRE Sara , PUGLISI Giuseppina Emma , OSORIO Thomas Jacques Francisco , RAMIREZ ESPINOSA Gustavo Adolfo , GIUSTO Edoardo , SHTREPI Louena , SERVETTI Antonio , MONTRUCCHIO Bartolomeo , PELLEREY Franco , PELLEGRINO Anna , ASTOLFI Arianna
Published: October 2024

Indoor Environmental Quality (IEQ) in university classrooms affects students' well-being, comfort and learning performance, thus its evaluation is strongly needed. This work presents an in-field study on the acoustic monitoring, along with thermal, visual and air quality domains, in
four recently built university classrooms of Politecnico di Torino. The monitoring was performed in the spring/summer and winter periods, through wall mounted multi-sensor devices. While the monitoring was ongoing, students attending lessons were asked to answer an online anonymous questionnaire
on comfort perception, which included questions regarding the four domains and additional personal information. Results show that students are more satisfied with the overall conditions in classroom 3P and more dissatisfied with the overall conditions in classroom 4P. The less satisfying domains
are the thermal and air quality ones, whereas the more satisfying are the acoustic and visual ones. Furthermore, at the increasing of TVOC and CO2 concentrations the overall satisfaction decreases. The final aim of this project, based on the monitoring results, is the optimization of the building
systems management to reduce energy consumptions and ensure occupants' well-being and comfort.
Measuring drone noise for environmental reviews
Authors: HOBBS Christopher , SUSUMU Shirayama , SCHOLTEN Adam , ROBINETTE Brandon
Published: October 2024

In the United States, federal actions are covered by the National Environmental Policy Act which requires a review process to assess a proposed action's potential impact on the environment. One of the environmental impact categories that must be considered is noise. In order to assess
the noise generated during a drone's typical operations, noise measurements of each portion of the drone's flight profile are needed. Because measurements required for type certification of aircraft are focused on source noise, they might not be sufficient to determine the noise resulting
from a drone's entire operation from takeoff to landing. This paper discusses a range of feasible noise measurement approaches for assessing a drone operation's noise characteristics along with their associated fidelity. The paper presents a suggested practical measurement protocol that a
drone manufacturer or operator could perform.
Measurements on the effect of vertical plucking angle of the kantele string
Authors: TAHVANAINEN Henna , HOCHMUTH Mathis
Published: October 2024

When a string instrument is plucked by hand, the player has the control over the plucking angle and the plucking position to influence the timbre. Different plucking angles will excite the vibrational modes of the strings differently. We designed a measurement rig to vary the vertical
plucking angle in a controlled manner. We measured four different plucking angles at three different plucking positions with the copper wire excitation method on the Finnish eleven-string kantele. The results show that the beating phenomenon of the string partials depends on the plucking angle.
The results can be used for example for sound synthesis purposes.
Understanding the influence of impedance transitions of acoustically reflective vertical surfaces on the frequency-dependent effectiveness of absorptive ceilings in large non-Sabinian empty spaces
Authors: RANDRIANOELINA Ando , LE RAY Pol , TROLY Maxime
Published: October 2024

An unexpected phenomenon was observed during measurements of reverberation time in empty spaces to be fitted out, in which the only sound absorbing treatment consists of mineral fiber tiles on the ceiling, a material typically highly absorbing at mid and high frequencies during laboratory
measurements: this involves a systematic increase of the reverberation time in octave bands between 1 kHz and 4 kHz in the measured empty spaces. The physical understanding of this surprising observation has focused on the question of the influence of impedance transition on sound scattering,
and the influence of the frequency-dependent scattering properties of acoustically reflective vertical surfaces of different natures (glazing, plasterboard lining, masonry) of these empty spaces on the efficiency of a sound absorbing ceiling. These scattering phenomena were studied and modeled
in a computer model in order to verify the model's adjustment hypothesis, an essential initial step before the study of the acoustic parameters in future fitted spaces and the effectiveness of acoustic solutions for space planning of open plane offices. Good consistency between the measurements
and the empty model was observed when the frequency-dependent scattering behaviour of the vertical reflecting surfaces of different nature was taken into account in the simulation.
Topologically protected bound modes in non-neighboring hexagonal lattices
Authors: DAL POGGETTO Vinicius F. , PAL Raj K. , PUGNO Nicola M. , MINIACI Marco
Published: October 2024

In the last decade, the study of wave localization and guiding has gained a renewed interest thanks to the introduction of the concept of topological protection. Originally developed in the field of quantum mechanics, topological protection has successively inspired the search for its
analogue in other physical domains, including elasticity. In this context, periodic hexagonal lattices have been proposed as ideal candidates to realize these concepts. In this work, we explore the dynamic behavior of discrete hexagonal lattices with third nearest neighbor connections. First,
the formation and transition of multiple Dirac cones above a critical value of the relative stiffness between the first and third nearest neighbor connections is derived. Then, the formation of extremely localized modes (i.e., bound modes) at the interface between regions formed by lattices
which are inverted copies of each other is demonstrated. Our results show that this localization derives from a type of interface satisfying a point reflection symmetry for which the considered chain decouples into two identical copies at the high symmetry point of the Brillouin zone. Our
findings open novel avenues for topological waveguiding and confinement with potential applications in surface acoustic wave devices.
Identification of flame transfer functions during transient operation
Authors: RADACK Florian , SCHUERMANS Bruno , NOIRAY Nicolas
Published: October 2024

Predicting thermoacoustic instabilities requires knowledge of the flame response to acoustic perturbations, which is characterized by the Impulse Response Function. Obtaining stability maps across an extensive parameter space is prohibitively costly with existing methods, both experimentally
and numerically, as the data records must be obtained independently for each stationary operating condition. To address this problem, a nonparametric identification technique that enables the characterization of instantaneous Flame Transfer Functions (FTFs) under nonstationary operating conditions,
based on a series expansion of the time-varying impulse response function (TV-IRF), is proposed. The technique is a direct extension of the Wiener-Hopf equation to nonstationary signals, yielding the linear minimum mean squared error estimator (LMMSEE) of the TV-IRF. This method is applied
to data obtained from a model of a premixed, hydrogen-enriched swirl flame. It's hydrogen power fraction is rapidly varied from 12-43% over 100 milliseconds and the flame response to a band-limited, white-noise signal is computed. From the resulting input-output data, the TV-IRF is accurately
estimated and the FTF for all hydrogen power fractions is obtained from a single data record. This method paves the way for cost-effective estimation of a map of FTF's from computational or experimental data, significantly reducing expenses in both cases.
Poroelasticity and acoustic properties of bio-based materials : from characterization to the understanding of mechanical dissipation effects
Authors: PIEGAY Clément , GLé Philippe , ANWAR Chems
Published: October 2024

The building sector is a key element in reducing the effects of climate change. To operate sustainably and efficiently, solutions based on building materials having a low environmental impact, such as bio-based materials, are needed. In fact, they present high-level multi-functional
properties and they capture atmospheric carbon dioxide. However, even if a number of works has examined visco-thermal dissipation effects, the understanding of the mechanical dissipation effects on the acoustic performances of bio-based materials is still incomplete and little data are available
in the literature. Therefore, it seems particularly relevant to investigate by experimental characterizations and modelling methods the effects of mechanical dissipation on the acoustic properties of a representative variety of bio-based materials such as vegetal wools, vegetal aggregate stacks
and vegetal concretes. To do this, Young's modulus, Poisson's ratio and structural damping were measured on the various typology of materials by a quasi-static analysis method. The non-linear elastic behaviour in compression of bio-based samples is analyzed. Finally, the influence of Young's
modulus and structural damping on the acoustic absorption and attenuation properties of bio-based materials is described using modelling approaches.
Environmental noise protection problems of Hungary's old heavy industrial areas
Authors: MARKUS Miklos
Published: October 2024

Hungary's first domestic environmental noise regulation entered into force in 1984. Several heavy industrial areas operate in the country, which were established in the first half of the last century or in the decades following the Second World War. During this period, aspects of environmental
noise protection were not yet considered. These heavy industry plants are usually located in huge industrial areas, operate thousands of diverse technological equipment and still remain significant factors of the Hungarian national economy. The reason for the development of the environmental
noise problem is that during the intensive socialist industrialization, to satisfy the huge demand for labor, they developed residential areas around the industrial areas. This led to a situation, when environmental noise protection legislation came into force, these heavy industry plants
found themselves in violation without any changes in their operations. The plants implemented noise reductions and attempted to comply with the limits, but mostly with little success. This presented an unsolvable problem to the plants, the authorities, and the residents too. The solution to
the problem is the introduction of regulations on the designated highly noisy areas and several additional measures, following the international practice of designating noise protection zones.
Preliminary sound walks alongside a planned metro infrastructure
Authors: PIANA Edoardo Alessio , MEDEGHINI Marco , GUARNIERI Fabio , ACQUATI Marco
Published: October 2024

The paper presents an experimental campaign carried out through a series of sound walks. Such measurements were performed to characterise the soundscape of the area where a future portion of a metro or tram line is going to be built. The sound walks aimed to acquire the data useful
to carry out a comparison between the ante opera situation and the post opera situation, thus predicting the perceived impact of the project. The post opera simulations were executed through an auralization of the prevalent sounds acquired on the field with the impulse responses computed through
the use of a ray tracing software.