bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving the Efficiency of Software Reliability Demonstration Testing by Introducing Testing Effectiveness
Authors: Li Qiuying , Zhang Limeng , Liu Shuo
Published: October 2024

For highly reliable software systems, it is expensive, time consuming, or even infeasible to perform reliability testing via a conventional software reliability demonstration testing (SRDT) plan. Moreover, in the traditional SRDT approach, the various characteristics of the software system or test sets are not considered when making the testing schemes. Some studies have focused on the effect of software testability on SRDT, but only limited situations were discussed, and many theoretical and practical problems have been left unresolved. In this paper, an extended study on the quantitative relation between test effectiveness (TE) and test effort for SRDT is proposed. Theoretical derivation is put forward by performing statistical analysis for the test suite according to TE. The combinations of all the cases of zero-failure and revealed nonzero failure, as well as discrete-type software and continuous-type software, are studied with the corresponding failure probability models constructed. That is, zero-failure and nonzero failure, as well as discrete-type software and continuous-type software, respectively, constitute the symmetry and asymmetry of SRDT. Finally, we illustrated all the models and performed applications on the Siemens program suite. The experimental results show that within the same limitation of requirements and confidence levels, this approach can effectively reduce the number of test cases and the test duration, i.e., accelerate the test process and improve the efficiency of the SRDT.
Field Ion Microscopy of Tungsten Nano-Tips Coated with Thin Layer of Epoxy Resin
Authors: Sobola Dinara , Alsoud Ammar , Knápek Alexandr , Hamasha Safeia M. , Mousa Marwan S. , Schubert Richard , Kočková Pavla , Škarvada Pavel
Published: October 2024

This paper presents an analysis of the field ion emission mechanism of tungsten–epoxy nanocomposite emitters and compares their performance with that of tungsten nano-field emitters. The emission mechanism is described using the theory of induced conductive channels. Tungsten emitters with a radius of 70 nm were fabricated using electrochemical polishing and coated with a 20 nm epoxy resin layer. Characterization of the emitters, both before and after coating, was performed using electron microscopy and energy-dispersive X-ray spectroscopy (EDS). The Tungsten nanocomposite emitter was tested using a field ion microscope (FIM) in the voltage range of 0–15 kV. The FIM analyses revealed differences in the emission ion density distributions between the uncoated and coated emitters. The uncoated tungsten tips exhibited the expected crystalline surface atomic distribution in the FIM images, whereas the coated emitters displayed randomly distributed emission spots, indicating the formation of induced conductive channels within the resin layer. The atom probe results are consistent with the FIM findings, suggesting that the formation of conductive channels is more likely to occur in areas where the resin surface is irregular and exhibits protrusions. These findings highlight the distinct emission mechanisms of both emitter types.
A Long-Term Assessment of Nitrogen Removal Performance and Microecosystem Evolution in Bioretention Columns Modified with Sponge Iron
Authors: Lin Zizeng , Shi Qinghuan , He Qiumei
Published: October 2024

The nitrogen removal performance of bioretention urgently needs to be improved, and sponge iron has great potential to address this challenge. This study reported the results of a long-term investigation on bioretention columns improved by sponge iron, examining the durability of sponge iron from nitrogen removal performance, sponge iron properties, and the evolution of biological elements. The results showed that after 9 months of continuous operation, the removal rates of ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), and total nitrogen (TN) in the bioretention columns with an appropriate proportion of sponge iron could reach 80% (some even over 90%). However, the long-term stress of sponge iron exposure, combined with the cumulative effect of pollutants, might lead to the excessive accumulation of reactive oxygen species (ROS) in plants, thereby posing risks of diminished chlorophyll content and enzyme activity. Simultaneously, the extended exposure could also have detrimental effects on microbial diversity and the abundance of dominant bacteria such as Proteobacteria and Sphingorhabdus. Therefore, it is necessary to select plant species and functional genes that demonstrate high adaptability to iron-induced stress.
The Role of Natural Killer Cells and Their Metabolism in HIV-1 Infection
Authors: Naidoo Kewreshini K. , Altfeld Marcus
Published: October 2024

Natural killer (NK) cells are multifaceted innate effector cells that critically influence antiviral immunity, and several protective NK cell features that modulate HIV-1 acquisition and viral control have been described. Chronic HIV-1 infection leads to NK cell impairment that has been associated with metabolic dysregulations. Therapeutic approaches targeting cellular immune metabolism represent potential novel interventions to reverse defective NK cell function in people living with HIV.
Full Genome Characterization of the First Oropouche Virus Isolate Imported in Europe from Cuba
Authors: Deiana Michela , Malagò Simone , Mori Antonio , Accordini Silvia , Matucci Andrea , Passarelli Mantovani Rebeca , Gianesini Natasha , Huits Ralph , Piubelli Chiara , Gobbi Federico Giovanni , Capobianchi Maria Rosaria , Castilletti Concetta
Published: October 2024

On 27 May 2024, the Cuban Ministry of Health reported the first outbreak of Oropouche fever on the island. The etiologic agent, Oropouche virus (OROV), is a poorly understood arbovirus that has been known since the 1960s and represents a public health burden in Latin America. We report the whole-genome characterization of the first European OROV isolate from a returning traveler from Cuba with Oropouche fever-like symptoms. The isolate was obtained from the patient’s serum; whole-genome sequencing was performed by next-generation sequencing, followed by phylogenetic analysis and genetic variability studies. The analysis showed that the most closely related sequence was from the French Guiana 2020 outbreak. Interestingly, our isolate is a reassortant virus, included in a highly supported monophyletic clade containing recent OROV cases (Brazil 2015–Colombia 2021), separated from the other four previously known genotypes. More deeply, it was found to be included in a distinct branch containing the sequences of the Brazil 2022–2024 outbreak. The reassortment event involved the S and L segments, which have high similarity with sequences belonging to a new cluster (here defined as OROV_SCDC_2024), while the M segment shows high similarity with older sequences. These results likely describe the viral strain responsible for the current outbreak in Cuba, which may also reflect the ongoing outbreak in Latin America. Further studies are needed to understand how OROV evolves towards traits that facilitate its spread and adaptation outside its original basin, and to track its spread and evolution in the European continent.
Interventions during Early Infection: Opening a Window for an HIV Cure?
Authors: Hiner Christopher R. , Mueller April L. , Su Hang , Goldstein Harris
Published: October 2024

Although combination antiretroviral therapy (ART) has been a landmark achievement for the treatment of human immunodeficiency virus (HIV), an HIV cure has remained elusive. Elimination of latent HIV reservoirs that persist throughout HIV infection is the most challenging barrier to an HIV cure. The progressive HIV infection is marked by the increasing size and diversity of latent HIV reservoirs until an effective immune response is mobilized, which can control but not eliminate HIV infection. The stalemate between HIV replication and the immune response is manifested by the establishment of a viral set point. ART initiation during the early stage limits HIV reservoir development, preserves immune function, improves the quality of life, and may lead to ART-free viral remission in a few people living with HIV (PLWH). However, for the overwhelming majority of PLWH, early ART initiation alone does not cure HIV, and lifelong ART is needed to sustain viral suppression. A critical area of research is focused on determining whether HIV could be functionally cured if additional treatments are provided alongside early ART. Several HIV interventions including Block and Lock, Shock and Kill, broadly neutralizing antibody (bNAb) therapy, adoptive CD8+ T cell therapy, and gene therapy have demonstrated delayed viral rebound and/or viral remission in animal models and/or some PLWH. Whether or not their application during early infection can improve the success of HIV remission is less studied. Herein, we review the current state of clinical and investigative HIV interventions and discuss their potential to improve the likelihood of post-treatment remission if initiated during early infection.
Development on Surrogate Models for Predicting Plume Evolution Features of Groundwater Contamination with Natural Attenuation
Authors: Wang Yajing , Wang Mingyu , Liu Runfeng
Published: October 2024

Predicting the key plume evolution features of groundwater contamination are crucial for assessing uncertainty in contamination control and remediation, while implementing detailed complex numerical models for a large number of scenario simulations is time-consuming and sometimes even impossible. This work develops surrogate models with an effective and practicable pathway for predicting the key plume evolution features, such as the distance of maximum plume spreading, of groundwater contamination with natural attenuation. The representative various scenarios of the input parameter combinations were effectively generated by the orthogonal experiment method and the corresponding numerical simulations were performed by the reliable Groundwater Modeling System. The PSO-SVM surrogate models were first developed, and the accuracy was gradually enhanced from 0.5 to 0.9 under a multi-objective condition by effectively increasing the sample data size from 54 sets to 78 sets and decreasing the input variables from 25 of all the considered parameters to a smaller number of the key controlling factors. The statistical surrogate models were also constructed with the fitting degree all above 0.85. The achieved findings provide effective generic surrogate models along with a scientific basis and investigation approach reference for the environmental risk management and remediation of groundwater contamination, particularly with limited data.
Temperature and Precipitation Change Assessment in the North of Iraq Using LARS-WG and CMIP6 Models
Authors: Abdulsahib Sura Mohammed , Zubaidi Salah L. , Almamalachy Yousif , Dulaimi Anmar
Published: October 2024

Investigating the spatial-temporal evolutionary trends of future temperature and precipitation considering various emission scenarios is crucial for developing effective responses to climate change. However, researchers in Iraq have not treated this issue under CMIP6 in much detail. This research aims to examine the spatiotemporal characteristics of temperature and rainfall in northern Iraq by applying LARS-WG (8) under CMIP6 general circulation models (GCMs). Five GCMs (ACCESS-ESM1-5, CNRM-CM6-1, MPI-ESM1-2-LR, HadGEM3-GC31-LL, and MRI-ESM2-0) and two emissions scenarios (SSP245 and SSP585) were applied to project the upcoming climate variables for the period from 2021 to 2040. The research relied on satellite data from fifteen weather sites spread over northern Iraq from 1985 to 2015 to calibrate and validate the LARS-WG model. Analysis of spatial-temporal evolutionary trends of future temperature and precipitation compared with the baseline period revealed that seasonal mean temperatures will increase throughout the year for both scenarios. However, the SSP585 scenario reveals the highest increase during autumn when the spatial coverage of class (15–20) °C increased from 27.7 to 96.29%. At the same time, the average seasonal rainfall will rise in all seasons for both scenarios except autumn for the SSP585 scenario. The highest rainfall increment percentage is obtained using the SSP585 for class (120–140) mm during winter. The spatial extent of the class increased from 25.49 to 50.19%.
Research on digital vibration model of typical components in pipe system
Authors: LIU Shuai , LIU Shuai , LI Wanyou , XIONG Furui , HUANG Xuan , FENG Zhipeng
Published: October 2024

The spatial distribution of pipe system is complex, long span and multi-point elastic support, so vibration analysis of pipe system is required in the pipeline design. This paper takes the pipe system as a typical component, based on the Timoshenko beam model, establishes a dynamic
procedure for straight pipe elements that considers the axial flow rate of fluid, the pressure on the pipe wall, the Poisson coupling effect of fluid and pipeline structure, and the axial, transverse and torsional vibration. Through Laplace transform, the frequency simplified dynamic model
is established. And the frequency transfer matrix model of straight pipe elements and the boundary constraint matrix of common boundary (such as fixed support) is established. Finally, the frequency domain transfer matrix model of different pipeline elements are set to the overall transfer
matrix of the flow pipe system, providing a convenient means for rapid optimization of pipe system vibration.
Acoustic metamaterials of double-layer structure for sound insulation
Authors: YU Yonghua , LI Zhi-Han , HUANG Weichun
Published: October 2024

Insulation against air-borne sound is one of the earliest research fields of acoustic metamaterials. The sound insulation of the conventional sound insulation structure is generally limited by the law of mass. When the density of the structural surface is doubled, the low-frequency
sound insulation is only increased by 6dB.In our report, we introduce a double-layer resonator-type acoustic metamaterial, which consists of two honeycomb sandwich panels, two perforated panels, and a thin air layer. Firstly, for two singer -layer resonator-type acoustic metamaterial, different
sound absorption frequency points were designed. Secondly, a calculation model of sound insulation metamaterial with double-layer resonator type is established. The results show that the sound insulation performance of the structure greatly breaks through the law of mass in the frequency range
of 165Hz-3150Hz. Finally, for the application requirements of the manufacturer, the compartment wall components and composite sound insulation door core components are designed. The reasonable design of Double-layer resonator-based honeycomb metamaterial structural parameters can solve the
problem of low-frequency noise of thin-layer lightweight structure.
Traffic road noise and transportation energy efficiency
Authors: ANTOINE Thomas , LE QUENVEN Alain , BOTTA Pierrick , THEVENARD Christophe , DESTREE Jerome
Published: October 2024

Future noise emission limits for passenger car are going to lower levels by 2024 -Social cost of noise for France in 2021, shows clearly that the dominant source of noise pollution is road traffic (81 Bn€ for a total of 146 Bn€) This R51 regulation is meant to lower the noise
pollution from road traffic, but when looking closer to the sources and their contributions, in particular the tire/road noise interaction, the environmental efficiency of this regulation is questionable. Tire/Road interaction involves tires characteristics, that are constrained by an array
of specification and it has been proven that there is a physical limit to what could be expected from the tire as far as tire/road interaction noise is concerned.Road surface however, shows very wide acoustic characteristics spread : over 15dBA from the quietest to the loudest asphalt, to
be compared to 2dBA steps in the regulation and an environmental impact that will depend on the rolling stock renewal rate. This paper will present a new patented method from Renault enabling to assess road acoustic data mapping from a simple drive of a Megane E-Tech, quickly and efficiently,
issuing the first ever noise pollution control maps.
Characterisation and subtraction of current flow noise in hydrophone recordings
Authors: TORRES-GUIJARRO Soledad , DORADO-PARADA Alejandro , SANTOS-DOMíNGUEZ David
Published: October 2024

In the interior of the Ría de Arousa, on the northwest coast of Spain, a hydrophone is installed to provide information on environmental noise, which is very high due to the intense traffic in the area. The hydrophone, together with various oceanographic and meteorological observation
equipment, is installed on a floating platform anchored in a very shallow water area with strong tidal currents. These currents cause flow noise that affects the estimation of the noise descriptors established by the Marine Strategy Framework Directive. The aim of this work is to characterise
the current flow noise at the hydrophone in relation to the instantaneous current measured simultaneously at the same location. From this characterisation, the current noise spectrum is defined and subtracted from the recordings prior to the calculation of noise descriptors. This contribution
provides details of the analysis of the hydrophone signals, the calculation of the flow noise spectrum as a function of current, the spectral subtraction procedure used and the effect of the subtraction on the calculation of the noise descriptors.
Dynamic control of Lamb modes in phononic crystals
Authors: MORVAN Bruno , MEKRACHE Kamel , SAINIDOU Reveka , REMBERT Pascal , STEFANOU Nikolaos
Published: October 2024

This study explores the possibilities of temporal control of one-dimensional phononic crystal consisting of a homogeneous piezoelectric plate on which metallic electrodes are structured. Previous works [1] have shown that Lamb-type guided modes in these periodically structured piezoelectric
ceramic plates exhibit a tunable frequency dispersion that can be controlled by external electric circuits connected to the electrodes. In this study we develop a device enabling changes in the electric boundary conditions (EBC) from one condition to another by making use of switches driven
by a microcontroller. This device agility is exploited to perform dynamic control of the crystal properties. To our knowledge, this is the first study devoted to the dynamic modulation of Lamb-type guided waves. Here, we do not simply change the EBCs as a function of time, but we create a
"wave" of modulation of properties. Broadband translation of Lamb-wave dispersion curves in the frequency-wavenumber space (f, k) are observed, depending on the modulation speed. Experimentally, the translation of the S0 mode is detected. The relationship between the position of
static bands and the position of bands after temporal modulation obeys a very simple vector rule in the (f, k) space. [1] Phys. Rev. B 99, 094302 (2019).
Virtual and experimental physical comfort testers for earplugs
Authors: SGARD Franck , POISSENOT-ARRIGONI Bastien , MELO Luiz , DALAQ Ahmed , WAGNAC Éric , DOUTRES Olivier
Published: October 2024

Earplugs are commonly used to prevent noise-induced hearing loss, but their efficacy is often hindered by discomfort, impacting consistent and correct use. Comfort of earplugs can be comprehended through four dimensions: physical (related to biomechanical and thermal interactions with
the earcanal), acoustical (linked to noise perception), functional (including usability and efficiency) and psychological (related to well-being and satisfaction). The evaluation of (dis)comfort involves intricate interactions among components of a triad formed by the user, the earplug, and
the work environment. Recent research by the authors has identified key psychosocial and physical characteristics of the triad influencing earplug physical discomfort. This study examines specific physical characteristics of the coupling between the "user" and "earplug"
components for disposable and reusable earplugs. Virtual and experimental comfort testers serve as modeling tools and test benches to enable this determination. Mechanical comfort testers of increased complexity designed to assess tribological characteristics of the earplug/earcanal system
are introduced. The study starts with simple benches measuring radial forces, extraction forces and friction coefficients, progressing to more advanced tools assessing mechanical pressure in various earcanal shapes either with rigid walls or lined with skin. This work aims at providing earplugs
comfort-driven design methods for manufacturers.
Efficient tuning of active sound design in electric vehicles - An interactive validation approach
Authors: HANK Stefan , KAMP Fabian , LOBATO Thiago , HEINRICHS Lars
Published: October 2024

The implementation of active sound design models in a target vehicle requires careful tuning of all synthetic sound elements with respect to existent vehicle interior noise, current driving conditions and general driving styles. Besides the creative aspects in sound design, this tuning
process is highly time-consuming. It must be ensured that load feedback, speed feedback and general interactivity with the synthetic sound meet the driver's expectations and match the intended emotional expressions of the sound concept. Testing the tuning parameters in real vehicles requires
access to the vehicle prototype and all involved system components, which is often not granted in early development stages. A key approach to overcome this difficulty is the application of acoustic driving simulator technology, directly linked to the main tuning parameters. Combining this
methodology with an efficient procedure for perceptive assessment of the sound design model, an interactive approach to active sound design is established. This paper discusses current progress in the field of efficient tuning of active sound design models, presenting a case study for a high-performance
electric vehicle.
An investigation into the audio-visual characteristics of restorative spaces using VR
Authors: KAWAI Claudia , GEORGIOU Fotis , PIEREN Reto , SCHäFFER Beat
Published: October 2024

The beneficial effect of nature on stress recovery is a topic of general importance, given that population growth, urbanization and thus noise-induced health impacts are likely to increase in the future. But what makes a recreational space 'restorative'? In this contribution, we present
findings from a laboratory experiment using VR environments, on the contributions of different audio-visual characteristics of restorative spaces. Self-reported restorative potential and acoustic quality were assessed in a repeated measures design, varying visual setting (forest, lake, urban
built space), soundscape (natural, anthropogenic), and sound pressure level (low, medium, high). First results indicate an additive effect of "naturalness": Restorative potential of spaces with both, natural visuals and natural sounds, was highest, but decreased significantly, when
(a) moderate road traffic noise (LAeq ≤ 52 dB) was present, or (b) the visual environment was a non-green urban space. Urban spaces with anthropogenic soundscapes were rated with the lowest restorative potential. While increasing sound pressure levels within an anthropogenic soundscape
decreased restorative potential, no such association was found for natural soundscapes. These results simultaneously highlight the beneficial effects of nature and the detrimental impact of road traffic noise on restoration.
Elasticity and modal effects on the optimal performance of micro-perforated multi-layered absorbers
Authors: MAURY Cédric , BRAVO Teresa
Published: October 2024

Multi-layered wall-treatments with thin lightweight micro-perforated panels offer a potential solution to achieve broadband noise absorption while complying with mass saving and compactness. This study examines how vibrational effects, often neglected, may impede the wideband acoustical
performance of such partitions, made up of a distribution of either periodic or graded micro-perforated membranes or panels. The impedance translation method and a scattering matrix analysis have been implemented. It is found that the elasticity behavior of thin micro-perforated membranes
has a beneficial effect on the acoustical efficiency of the partitions. The contributions of the individual acoustical resonances tend to merge if the elasticity effects are accounted for. If the partition is optimized, near-constant high absorption and low transmission values are obtained
over a wide frequency range. A more robust design involves partitions made up of micro-perforated panels. It was observed that the first volumetric volumetric mode of the panels modifies the absorption properties of the partition. It cross-couples with the acoustical resonances and redistributes
their spectral locations. This structural resonance sets an upper frequency bound, below which the partition achieves a high broadband performance. It should be accounted for when setting the frequency limits of the total dissipation to be optimized.
Development of an experimental technique for measuring polar diagrams of adaptive directivity implemented in hearing aids
Authors: MAILLOU Balbine , DUCOURNEAU Joël
Published: October 2024

Nowadays, hearing aids have efficient signal processing options to improve speech intelligibility in noise. This work concerns the characterization of the microphone systems directivity available in hearing aids. In recent decades, "adaptive" directivities have been implemented
in hearing aids, thus making it possible to focus on useful sound sources in the hearing aid patient environment. These options use the principles of sound environments detection, acoustic beamforming and noise reduction. Performances of these options can be estimated with subjective methods
(as speech audiometry in noise), and objective methods (listening effort, intelligibility indicators as HASPI, SII, STI, etc.). But these methods provide an overall assessment of all the processing involved in speech enhancement and are not designed to characterize the effects of adaptive
directivity. We developed an experimental technique based on sound sources separation with phase opposition diffusion (known as "Hagerman" method) to draw polar diagrams of adaptive directivity, for realistic sound environments. We used a sound multi-diffusion system to generate
various sound environments with noise and speech sources around an artificial head equipped with hearing aids. The first results show the adaptive directivity effects associated with noise reduction provided by the latest hearing aids generation on everyday hearing scenes.
Impact of surrounding environment on impinging supersonic jets resonances and their hysteretical behavior
Authors: BELTRA Pierre , JAUNET Vincent , LEHNASCH Guillaume , MANCINELLI Matteo
Published: October 2024

Supersonic jets impinging on flat surface produce intense acoustic tones. Recent measurement campaigns have indicated that the surrounding environment geometry or its acoustic treatment can drastically change the observed resonance frequencies and amplitudes at identical flow regimes.
For example, at supersonic speeds, a hard walled external nozzle shape leads to the existence of two main types of resonances: antisymmetric resonances (with frequencies close to the free jet screech) and axisymmetric resonances. Frequencies associated to those different resonances are very
distinct. We have observed that Applying a simple non-reflective material to the outer surfaces of the nozzle suppresses the axisymmetric resonances and that antisymmetric resonances seems to be contained in the frequency range of existence of trapped acoustics modes, known to be responsible
for screech resonances. Additionally, when no acoustic treatment is applied on the nozzle wall, the experiments show that the switch between different resonance regimes (symmetric - antisymmetric), induced by changes in Mach number, has an hysteretical behavior. To the authors' knowledge,
this has been rarely discussed in the literature and adds to the actual complexity of the aeroacoustic behavior of such jet flows, especially when modeling is considered.
The development of a bio-inspired vibration source localization algorithm
Authors: WU Jun , MILLER Thomas , TAYLOR Graham , MORTIMER Beth
Published: October 2024

Vibration source localization is an interdisciplinary topic that has applications in both engineering and biology. To develop bio-inspired technologies that can be applied in engineering, a vibration source localization algorithm is developed based on a spider dynamic model. The model
includes: (i) a point source; (ii) a spider model with 8 legs resting on a non-dispersive substrate that introduces correlated leg inputs. The proposed algorithm first calculates the leg inputs using a backward filter forward smoother algorithm with given leg responses to the excitation from
the vibration source; and then estimates the source angle, source distance, wave speed and decay rate through optimization. The optimization utilizes the time and amplitude relationships between the leg inputs and the leg-substrate contact locations. The effectiveness of the algorithm is validated
by comparing the algorithm estimations with the actual parameters. Results show that the algorithm gives accurate estimation of the source angle and wave speed usually with errors within 3 deg and 1 m/s, respectively, but cannot estimate the source distance. Two spatially-separated spider-like
models are needed for estimating the source distance. The algorithm works well even under low signal-to-noise ratio down to 11 dB.
Towards situation dependent radiation efficiency
Authors: GUIGOU CARTER Catherine , VILLOT Michel
Published: October 2024

Designing buildings to protect inhabitants against ground-borne noise from railway lines or other outdoor ground vibration sources has become a subject of importance. Prediction methods to tackle such a problem are under discussion within a European task group (CEN/TC126/WG2/TG1). From
velocity response of floors and walls, the structure-borne sound level has to be evaluated; the linking quantity is the radiation efficiency. In the frequency range of interest, i.e. covering the one-third octave bands from 16 to 250 Hz, rooms modes exist for standard size living spaces in
building. A parametric investigation is carried out to evaluate the effect of the room modes on the radiation efficiency. In a first step, a modal approach is used to estimate the radiation efficiency for different room sizes, heavy floor and light wall types. Randomly positioned forces are
considered as excitation on these structural elements. From these results, the situation dependent radiation efficiencies are investigated and discussed.
Establishing a benchmark for comparative analysis of thin and thick plate modal frequencies: A non-dimensional paradigm
Authors: DURAN Sebastian , TAHVANAINEN Henna , DUCCESCHI Michele
Published: October 2024

This study presents a methodological framework to establish a standardised baseline for comparing the vibrational characteristics of thin and thick rectangular orthotropic plates in acoustics. The research addresses the inherent difficulties associated with varying plate parameters
by proposing the use of non-dimensional frequencies for comparative assessments. It will be shown that, under the thin-plate approximation, plates with identical aspect ratios, boundary conditions, and elastic constant ratios exhibit identical non-dimensional modal frequencies and shapes.
The proposed methodology involves generating baseline non-dimensional frequencies and modal shapes via numerical simulations for a reference plate with specified parameters. Subsequent analysis entails systematically varying plate thickness and determining the number of modes that yield the
same non-dimensional frequencies within a predefined deviation of the baseline. Notably, the comparison is conducted on an eigenshape basis, thereby circumventing the consideration of dimensional frequencies. This approach offers a structured framework for comparative analysis, centred on
identifying modes exhibiting thin behaviour regardless of dimensional frequency, thus enhancing the objectivity of modal characterisation.
Comparison of loudness calculation procedures according to ISO 532-1 and DIN 45631/A1
Authors: SOTTEK Roland , BECKER Julian , FASTL Hugo , FEDTKE Thomas , FIEBIG André , GENUIT Klaus , LETENS Uwe , VON POZNIAK Jan-Martin , SCHEUREN Joachim , VERHEY Jesko L. , WARTINI Stefan
Published: October 2024

In 2017, the standard ISO 532-1:2017 "Method for calculating loudness - Part 1: Zwicker method" was published. The method described in this standard for calculating loudness of time-varying sounds is based on the algorithm published in DIN 45631/A1:2010 "Calculation of
loudness level and loudness from the sound spectrum - Zwicker method - Amendment 1: Calculation of the loudness of time-variant sound". With the publication of the German translation of ISO 532-1:2017 (DIN ISO 532-1:2022) in 2022, there are currently two DIN standards available that describe
the calculation of loudness using the Zwicker method for time-varying sounds. In this paper, the two methods, described in ISO 532-1:2017 and in DIN 45631/A1:2010, are compared and the extent to which the calculated loudness of the two methods differs is investigated. These results are used
to check whether the results of ISO 532-1:2017 are within the tolerances for loudness calculation described in DIN 45631/A1:2010.
Resonant frequencies of multi-layer building constructions: Estimation by measurement of acceleration amplitudes
Authors: VAVříK-KIRCHSTEIGER Selina , FERK Heinz
Published: October 2024

The Austrian building regulation requirements for impact sound insulation are based on the weighted standardized impact sound pressure level as single-number specification. In recent years, it has become apparent that not only the single-number specification, but the extended frequency
range and frequency characteristics of impact sound insulation of constructions can have noticeable influence on the perceived acoustic performance of a construction. Therefore, the Austrian Classification Standard ÖNORM B 8115-5: 2021-04 includes extended requirements on impact sound
insulation. It provides two ways for verification of the sound insulation classes A to C. One way is the verification via the resonance frequency of multi-layer constructions. However, there exist as yet no standardized measurement methods for the estimation of the resonance frequency of multi-layer
building constructions. In response, in course of this study a new measurement method for the estimation of the resonance frequencies of multi-layer constructions was developed. For this development acceleration measurements were carried out on both surfaces of particularly double-layer building
constructions, that were excited with a rubber hammer. From these measurement results, in conjunction with an analytical model, it was possible to derive a measurement method for estimating the resonant frequency via the frequency characteristics of the acceleration amplitudes.
Towards estimating acoustic surface impedances at low frequencies in a reverberation chamber
Authors: PRINN Albert , LATORRE IGLESIAS Eduardo , LóPEZ-IBáñEZ María , LARROSA-NAVARRO María , HABETS Emanuël
Published: October 2024

To accurately simulate interior acoustical fields, reliable descriptions of the physical properties of the acoustical space are required. While geometry, propagation medium properties, and source characteristics are, in general, easily accessible, the absorption characteristics of the
bounding surfaces of a space can be difficult to obtain. For commonly used materials, databases of absorption coefficients could be used. However, absorption coefficient databases are of limited use at low frequencies, especially below 100 Hz. Furthermore, measurement-based estimations tend
to be more reliable. Thus, there is incentive to perform measurement-based estimations of the absorption characteristics of a room's bounding surfaces at low frequencies. This work considers the estimation of sound absorption, given in terms of locally-reacting surface impedance, at modal
frequencies. This is made feasible by solving an inverse eigenvalue problem. The spatially-uniform, frequency-dependent impedance of the bounding surfaces of a reverberation chamber is estimated. The method is validated by comparing measured transfer functions to simulated transfer functions,
which are generated using the estimated impedance. It is shown that the proposed method can be used to estimate locally-reacting surface impedance from measured room impulse responses at low frequencies.
Identification of radiated modes by a small-scale ducted fan
Authors: BUBA Michael , PEREIRA Antonio , BAILLY Christophe , MAEDER Marcus , MARBURG Steffen
Published: October 2024

Various industrial applications involve fluid flow in ducted fans. Turbojet engines or air condition systems are just a few examples. The long-term objective is to reduce the associated noise pollution generated by rotor-stator interaction within a small-scale duct. Modal detection
strategies help to understand the characteristics of sound radiation of such systems involving fluid flow. In this work, the authors analyze the modal amplitudes generated by a rotor-stator interaction in the presence of a background mean flow. The inverse approach detecting the modal amplitudes
is applied using experimentally as well as numerically determined sound pressure values outside the circular duct. The results are discussed and compared against mode amplitudes estimated by an in-duct microphone array whose data is measured simultaneously with that of the far-field one. Some
physical interpretations regarding varying amplitudes are discussed. The approach is finally used to assess the impact of homogeneous and heterogeneous stator vanes on the rotor-stator generated noise.
A method of estimating degree of influence from wind for improving sound source localization in windy place
Authors: TAKAHASHI Toru , MATSUMOTO Shintaro , NAKAYAMA Masato
Published: October 2024

In this paper, we propose a method for visualizing the influence of wind on sound propagating in a room where wind is blowing, and rating the degree of influence. Since non-uniform airflow affects sound propagation and gives time-variant characteristics to the transfer function, a method
is needed to understand the influence of wind. Therefore we propose a method that measures impulse responses multiple times indoors, determines a similarity matrix between impulse responses, and visualizes it as a heatmap. We evaluate the proposed method in four types of average wind velocity
(0.0 m/s, 2.7 m/s, 3.3 m/s, 3.9 m/s). The result of the evaluation showed that the greater the influence of the wind, the higher the value of diagonal elements of the similarity matrix than off-diagonal elements, and the tendency for diagonal elements to be emphasized. We also confirm that
the rating based on the Frobenius norm of the similarity matrix takes a lower value as the influence of the wind is greater.
Experimental modal analysis of in-plane bending vibration mode using actual water main network
Authors: WATANABE Naoko , TAKATA Soichiro , TOYOSHIMA Koji
Published: October 2024

Accidents of water leakage and bursting due to deterioration of water pipes cause water outages and economic losses in the surrounding areas. We are conducting research to develop measurement and diagnostic methods for buried water pipes. The graphitic corrosion of water pipes in a
buried environment causes a reduction in pipe thickness which leads to strength problems. For this reason, methods for detecting pipe thickness are necessary for evaluating pipe deterioration, however, there is no effective way to analyze pipe thickness today because it cannot be visually
observed in a buried environment. In this study, we focused on the shift in eigenfrequencies of in-plane bending vibration of rings due to deterioration. At first, we performed an experimental modal analysis by using a water pipe network which is used in a practical water utility. In addition,
we conducted a theoretical analysis based on a model of a two-dimensional ring with coupled incidental attachment. As a result, in-plane bending vibration was observed in the water pipe of actual size. Furthermore, in-plane bending vibration was observed when excited through fire hydrants
and it is also observed in pipes that are different material and diameters.
Prototyping of vibration-sensing-actuation device which is contained high-power electrodynamic speaker for diagnosis of actual water main network
Authors: TAKATA Soichiro , TOYOSHIMA Koji , KUBOTA Shuya
Published: October 2024

Water leakage and bursting due to deterioration of water distribution mains lead to water outages and economic losses. To prevent the accidents, we are conducting research to develop measurements and diagnostic methods for buried water mains. In this study, we focused on the shift in
eigenfrequencies of in-plane bending vibration of rings because of deterioration. Therefore, we are developing the vibration-sensing-actuation device which detects the frequency changes of in-plane bending mode. The water distribution network is mainly composed from cast iron pipe. Moreover,
the attached facilities for example fire hydrant and water valve are contained. Since attached facilities are fabricated from cast iron component, actual water main network is heavy facilities which have high rigidity. In order to excite the desired in-plane bending mode in heavy components,
the proposed sensing-actuation device requires the high-power actuator. In this study, we introduce the high-power electromagnetic actuator more than 100W output into the proposed device. Furthermore, the fundamental operational tests were conducted under the various input signals in the laboratory
situations. In addition, the field operation confirmation was performed in an actual water main network.
Measurement of sound reflection and sound insulation of installed noise barriers using the SOPRANOISE quick method
Authors: GUIDORZI Paolo , GARAI Massimo
Published: October 2024

This paper presents the preliminary results of a study on the new possibilities emerging from the analysis of measurements on installed noise barriers following the quick method designed in the frame of the SOPRANOISE project. Measurements of sound reflection and sound insulation were
done in laboratory on a full-scale acoustic barrier and on an acoustic barrier installed along the Brennero motorway in northern Italy. The measurements were carried out using the SOPRANOISE quick system device, designed and engineered to provide a fast and lightweight version of the Adrienne
method (i.e., EN 1793-5 and EN 1793-6), and then checked by applying the standardized Adrienne method, using instrumentation and procedures validated during the round-robin test performed in the frame of the QUIESST project. The preliminary results of the measurements are presented.
Sound absorption properties of different green wall systems
Authors: KULAK DALKILIC Seda , YAZICIOGLU Fatih
Published: October 2024

Façade of the buildings generally consists of acoustically rigid materials. They reflect or scatter sound emitting from sound sources especially main roads thus affects sound environment in a negative way. Applying green walls can be nature-based solution to these urban scale
noise. The aim of this research is to compare green wall systems in terms of sound absorption and to determine which one is more effective. Sound absorption at normal incidence of 8 different green wall systems measured via impedance tube in accordance with TS ISO EN 10534-2 standard for 50-6400
Hz. The ivy type, evergreen Hedera Helix plant was used. Potting soil or felt or rock wool was used as a growth medium. As a result, it was seen that the sound absorption of the 'plant + 20 cm potting soil + 10 cm air gap' green wall system was higher than the others. It is followed by the
system with 'plant + 20 cm potting soil', 'plant + 3 cm felt + 10 cm air gap' and 'plant + 3 cm rock wool + 10 cm air gap' systems. The sound absorption value was found to be lowest when the plant was applied only as a green façade.
Numerical investigation of vibratory response of planetary gear sets and modulation effects induced by carrier rotation
Authors: NEUFOND Jessica , PERRET-LIAUDET Joël , RIGAUD Emmanuel , BOUVET Pascal , PARPINEL Adrien
Published: October 2024

In geared system, the main source of excitation is generated by the mesh process itself. Depending on the dynamic conditions involved, the system may present a variety of problems, ranging from acoustic nuisance to system failure. Predicting and controlling the mesh process at an early
design stage is a key point to avoid such issues. The problem is complex, mainly due to its multi-scale nature. Indeed, the vibroacoustic behavior of geared systems (on the scale of a meter) depend on the local micro-geometry of the teeth (of the scale of a micron), associated with the transmission
error. Moreover, the problem is parametric in nature, due to the periodic fluctuation of the mesh stiffness. These parametric internal excitations generate dynamic mesh forces which are transmitted to the housing through wheel bodies, shafts and bearings. In the case of planetary gear sets,
the numerical prediction presents a complementary challenge as, in many application, the carrier rotation modulates the housing vibration response, at its rotational frequency. This paper present an original simulation process to deal with modulation effects in planetary gear systems.
Sound quality improvement technique for inverter-driven motors
Authors: WATANABE Masanori , TANABE Yosuke , HARA Takafumi
Published: October 2024

Motor-driven products are becoming increasingly popular along with the trend toward carbon neutrality. Motor units driven by PMW inverters are one of the key components of motor-driven products, but since they are also one of the dominant sound sources, there are high demands for quietness,
including sound quality improvement, in terms of comfort. During the DC-AC conversion process, the PWM inverter generates harmonic current distortions and, moreover, the electromagnetic excitation forces generated in the air gap between the rotor and stator induce harmonic vibrations in the
motor. Therefore, this presentation describes the mechanism of motor noise generation from the excitation source to propagation and radiation, and activities to improve sound quality for the motor unit driven by inverters.
Acoustic properties of perforates - experimental data and empirical models
Authors: BODéN Hans , SHAIL Shail A. , BOIJ Susann
Published: October 2024

Sound reducing treatment in for instance aircraft engine and IC engine applications often involve the use of perforates. In these applications they are exposed to fluid flow and high-level acoustic excitation, and this influences the acoustic properties of the perforate, as is well
known from many published papers. The acoustic properties are usually described using a transfer impedance. The transfer impedance of a perforate sample has been studied using both a conventional impedance tube (two-port) setup and an innovative three-port setup. The three-port configuration
made it possible to study both the effect of grazing flow and high-level excitation effects separately as well as jointly. In the present paper these recent experimental results are presented and comparisons are made with results from previously published papers and empirical models.