Hasil untuk "Acoustics. Sound"

Ke'er Xiao, Lingyu Gao, Qiuyu Lu et al.

This study investigated the synergistic effect of ultrasound in combination with pH-shifting and heating modification on the physicochemical properties, structural characteristics, and emulsifying performance of safflower seed meal globulins (SMG). Furthermore, the efficacy of the modified protein (UHA-SMG) as a natural emulsifier was evaluated for preparing lycopene (LYC)-loaded high internal phase emulsions (HIPEs). Under the suitable modification conditions (ultrasonic power: 500 W, ultrasonic time: 5 min, temperature: 70 °C, pH: 9.0), UHA-SMG exhibited improved physicochemical properties, including altered micromorphology, reduced particle size and interfacial tension, as well as enhanced zeta-potential, surface hydrophobicity, wettability, and solubility. Structural characterization via far-UV circular dichroism, UV–Vis spectroscopy, and fluorescence spectroscopy indicated that the modification altered the secondary and tertiary structures of SMG, as evidenced by a rise in α-helical content and the redistribution of internal hydrophobic groups and aromatic amino acids. At a concentration of 2.0% (w/v), UHA-SMG successfully stabilized oil-in-water HIPEs with an internal phase volume of 75%. These HIPEs demonstrated typical shear-thinning behavior, gel-like rheological characteristics (G' > G''), and excellent stability against centrifugation, heating, and long-term storage. For LYC encapsulation, the HIPEs formulated with 2.0% (w/v) UHA-SMG achieved a high encapsulation efficiency of 96.39 ± 1.34% and provided markedly enhanced stability of LYC against UV irradiation, thermal degradation, and storage compared to free LYC. In summary, the synergistic triple-modification strategy (ultrasound, heating, and pH-shifting) significantly enhanced the functionality of SMG, rendering it a promising candidate as a bio-based stabilizer for HIPEs with considerable potential in lipophilic bioactive ingredient delivery systems.

Márcio Marques, Leonardo Mendonça, Arthur Bizzi et al.

Physics-informed neural networks (PINNs) have emerged as a promising tool for simulating various phenomena. However, their application in underwater acoustics remains challenging, primarily due to the need to sample large computational domains and to convergence to trivial solutions. This study presents a strategy to address these issues by combining adaptive domain sampling with absorbing boundary conditions. The adaptive sampler dynamically focuses computational effort on regions where the acoustic energy is localized, while the absorbing boundaries perform training stabilization. Numerical experiments show that our method improves the stability and convergence of PINN training, leading to more accurate and reliable wave propagation simulations.

Nayereh Seyed Afiuny, Amir Lakizadeh

Abstract Voice conversion (VC) transforms a source speaker’s voice into that of a target speaker while preserving the underlying linguistic content. However, existing methods, especially for languages with complex phonetic structures like Persian, often struggle with issues such as over-smoothing, inadequate multi-scale feature extraction, and loss of essential acoustic details. In this paper, we introduce ICRCycleGAN-VC, an innovative one-to-one voice conversion framework that integrates Inception-ResNet modules into a CycleGAN architecture. By leveraging multi-scale convolutional filters, residual connections, and an optimized loss function strategy that eliminates second adversarial losses in the generator, our approach significantly improves the preservation of linguistic content, addressing the main challenge of ensuring accurate content retention. Extensive experiments on both Persian and English datasets demonstrate significant improvements, achieving notable reductions in mel-cepstral distortion and root mean squared error compared to baseline models such as MaskCycleGAN-VC. Furthermore, subjective evaluations reveal a substantial increase in both voice similarity and naturalness. Ablation studies highlight the critical contributions of each architectural component, confirming the robustness of our approach in advancing non-parallel voice conversion.

Xin-Jue Lai, Jian-Quan Chen, Jing Nie et al.

Chickpea protein isolate (CPI) is a promising dietary protein with the advantages of low allergenicity, easy digestion and balanced composition of essential amino acids. However, due to the thick skin of chickpeas, the extraction of CPI is challenging, resulting in lower efficiency of the alkaline extraction-isoelectric precipitation (AE-IEP) method. Therefore, the present study investigated the effect of pulsed electric field combined with ultrasound (PEF-US) treatment on the extraction efficiency of CPI and the functional properties was characterized. Parameter optimization was carried out using response surface methodology (RSM), with the following optimized conditions: pulse duration of 87 s, electric field intensity of 0.9 kV/cm, ultrasonic time of 15 min, and ultrasonic power of 325 W. Under the optimized conditions, the yield of CPI after combined (PEF-US) treatment was 13.52 ± 0.13 %, which was a 47.28 % improvement over the AE-IEP method. This yield was better than that obtained with either individual PEF or US treatment. Additionally, the functional properties (solubility, emulsification, and foaming) of CPI were significantly enhanced compared to AE-IEP. However, the stability of emulsification and foaming did not show significant differences among the four methods. The PEF-US method efficiently extracts CPI with excellent functional properties, enabling the production of proteins as desired functional additives in the food industry.

Moath N. Zaareer, Abdel-Hamid Ismail Mourad, Tariq Darabseh et al.

Extreme effect of noise pollution includes deafness and mental breakdown and in main cities automobiles are a main source of noise. The literature concentrates on the side mirror part and lacks analysis on mirror base (arm) that connects the mirror part to the vehicle's body. This work focuses on lowering noise emission from vehicles by optimizing the orientation of the mirror base. In this manuscript, the connection between the mirror and its base is set as a vertical rotational axis, and multiple angles are examined to determine the optimal angle for the mirror base ranging from 0 to 90°. The Scale Adaptive Simulation (SAS) model is utilized for the simulation combined with Ffowcs-Williams and Hawkings as the acoustics model. The simulation is conducted using ANSYS Computational Fluid Dynamics to analyse the real case. The results show that, the optimal orientation of the mirror's base is ∼85° relative to the horizontal axis, as it yields minor acoustic noise and relatively the best aerodynamic force performance. The difference in changing the mirror base orientation results up to 32 dB difference in sound pressure level.

Kottapalli Shravan, van de Meerendonk Remco, Waterson Nicholas et al.

Transmission losses of compact compliance-based resonators in water circuits are investigated. Experiments are performed to measure the anechoic transmission losses (TLan) of flexible-plate resonators and a gas resonator designed for frequencies between 10 and 100 Hz. The measurements are compared to theoretical results based on a lumped-element model and a finite-element model. The TLan is measured using a robust form of the multi-microphone method, which gave identical results for open and closed pipe acoustic terminations at the transmission side of the setup. When an estimate of the reflection coefficient at the termination is known, good results are obtained with only one transmission-side microphone. When TLan is high, a single microphone is sufficient on each side. For the flexible-plate resonators the TLan measurements are in agreement with theory except close to resonance, where the transmission signals are below the detection limit. Due to assumptions of a rigid cavity wall and a clamped top-plate, the theoretical resonance frequencies are too high except for the thinnest plate which displays static deformation stiffening. This deformation stiffening limits the possibility to lower the resonance frequency by using a thin flexible plate in a circuit with high static pressure. Low resonance frequencies are easier to reach with a gas resonator, in which a piston separates the water from a volume filled with air. For the gas-resonator, the measurements agree with the theoretical predictions when assuming a significant damping. The friction between the air-water-separation piston and cavity wall is suspected to cause this damping. Theory predicts that the TLan of both resonators designed for same resonance frequencies in absence of losses are equivalent. They therefore have quite similar performances except close to the resonance frequency. The flexible-plate resonator has a higher quality factor and higher (TLan) around the resonance frequency. The gas resonator is more complex and needs more maintenance but allows fine tuning of the resonance frequency by varying the gas volume.

Julie Meyer, Michael Smirnov, Ali Khajeh-Saeed et al.

This paper presents a verification procedure for finite-difference time-domain-simulated head-related transfer functions (HRTFs) from a simplified model of a human head, a sphere. The analytic solution required by the code verification is computed with the multipole reexpansion technique and used to estimate convergence rates. A solution verification process follows in which asymptotic predictions are computed. For the HRTFs considered and employed grids, results show that the convergence rates attain the expected first-order accuracy at lower frequencies, after which scattered estimates are observed. Results also reveal that the asymptotic predictions are accurate up to 10 kHz, after which bias is observed.

J. Vonk, J. Kukačka, P.J. Steinkamp et al.

Oral cancer patients undergo diagnostic surgeries to detect occult lymph node metastases missed by preoperative structural imaging techniques. Reducing these invasive procedures that are associated with considerable morbidity, requires better preoperative detection. Multispectral optoacoustic tomography (MSOT) is a rapidly evolving imaging technique that may improve preoperative detection of (early-stage) lymph node metastases, enabling the identification of molecular changes that often precede structural changes in tumorigenesis. Here, we characterize the optoacoustic properties of cetuximab-800CW, a tumor-specific fluorescent tracer showing several photophysical properties that benefit optoacoustic signal generation. In this first clinical proof-of-concept study, we explore its use as optoacoustic to differentiate between malignant and benign lymph nodes. We characterize the appearance of malignant lymph nodes and show differences in the distribution of intrinsic chromophores compared to benign lymph nodes. In addition, we suggest several approaches to improve the efficiency of follow-up studies.

Michael A. Akeroyd, Jennifer Firth, Simone Graetzer et al.

The variation of interaural level difference (ILD) with direction and frequency is particularly complex and convoluted. The purpose of this work was to determine a set of parametric equations that can be used to calculate ILDs continuously at any value of frequency and azimuth in the horizontal plane. They were derived by fitting equations to ILDs derived from the azimuthal-dependence data tabulated by Shaw and Vaillancourt [(1985). J. Acoust. Soc Am. 78, 1120–1123] and assuming left-right symmetry. The equations are shown to fit those data to an overall RMS error less than 0.5 dB.

Laurianne Delcor, Etienne Parizet, Julie Ganivet-Ouzeneau et al.

Vibrations contribute to helicopter’s ride comfort. This study aimed to determine the relationship between main rotor vertical excitations and discomfort. Fifty-three participants, seated on a helicopter seat fixed to a vibration test bench, evaluated the discomfort of vertical sinusoidal vibrations using a magnitude estimation procedure. Stimuli had a frequency between 15 and 30 Hz and a level between 0.32 and 3.16 m/s 2 . The average discomfort was shown related to vibration velocity using Steven’s power law, without any frequency dependence. The exponent depended on velocity and was 1.18 for higher velocities (approx. above 0.008 m/s) and 0.65 for velocities below that limit.

Mirna Sabbouh, Anna Nikitina, Elizaveta Rogacheva et al.

The mathematical method of separation of motions represents the effect of fast high-frequency oscillations by an effective averaged force or potential. Ultrasound acoustic vibrations are an example of such rapid oscillations leading to cavitation in water due to the gas phase formation (bubbles). Ultrasound cavitation is used to treat the surface of brass microparticles submerged in water. The formation of bubbles and their collapse triggers the modification of surface roughness and chemical composition. Consequently, the suspension separates into various fractions related to demonstrating biocide properties. While the exact mechanism of this process is complex, it can be explained phenomenologically by using the Onsager reciprocal relations for coupling the copper ion diffusion with the gas phase separation in water as a result of the action of the effective average vibrational force.

C. Aguilar, J. Serna-Jiménez, E. Benitez et al.

Raw meat emulsions may have natural, spoilage and pathogenic microorganisms due to the origin and characteristics of this food matrix. All of these microorganisms must be minimized during industrial processing to make food consumption safe and meet quality regulations. Therefore, in this research, the effect of probe ultrasound on the inactivation of three kinds of microorganisms in a raw meat emulsion is evaluated. The microorganisms are: natural microflora NAM, Listeria monocytogenes LIS, and Lactobacillus delbrueckii LAC. A high-intensity probe ultrasound system was used, during 1.0, 2.5, 5.0, 7.5 and 10 min, with pulsed waves of 0.0, 10, 20 and 30 seg, and 200, 250, 300, 350 and 400 W of power. The interrelation between time, wave pulse cycle, and power factors was assessed. The results showed a positive linear independence effect in the treatments without wave pulse for each microorganism, and a quadratic interaction with the time and the ultrasound power for the inactivation of the three kinds of microorganisms. Besides, the desirability function for the inactivation reached up to 60% of the microbial population with the probe ultrasound treatment, with 10 min, a 7.56 s wave pulse and 400 W of power. Thus, these results could be useful to decide the incorporation of mild and emerging technologies in a meat industry line process.

Stanislaw Wrona, Marek Pawelczyk

The active casing approach is a technique to reduce noise emission of devices and machinery by controlling vibrations of their casings. This method was successfully validated by the authors for a single-panel casing in previous publications. However, if even higher noise reduction is required, a dedicated double-panel structure can be employed. In this paper, the sound insulation efficiency of a double-panel active casing is evaluated and compared with a single-panel structure by performing a series of laboratory experiments. The least mean squares algorithm is used to adaptively update control filter parameters. A low-frequency noise in the range up to 500 Hz is considered. Advantages and limits of the proposed approach are pointed out and discussed, and conclusions for future research are given.

Federica Morandi, Alessandro Marzani, Simona De Cesaris et al.

Il presente contributo riporta un'introduzione al tema della propagazione del suono nei cristalli sonici e un excursus sulla letteratura scientifica più recente. Si discutono i risultati di alcune indagini sperimentali condotte presso l’Università di Bologna inerenti misure di Insertion Loss, misure effettuate all’interno del reticolo e misure di intensimetria. Infine i valori di Sound Insulation misurati per un cristallo sonico sono confrontati con valori misurati su barriere tradizionali, evidenziando come il cristallo sonico permetta di raggiungere un isolamento confrontabile con il valore soglia di Insertion Loss raggiungibile a causa della diffrazione del bordo superiore della barriera. ------ This work reports an introduction to the topic of wave propagation in sonic crystals and a review of the recent scientific literature. The paper presents the results of some experimental investigations carried out at the University of Bologna by discussing Insertion Loss measurements, measurements performed inside the lattice and sound intensity measurements. Finally, the Sound Insulation Index measured for a sonic crystal is compared to the values measured for common noise barriers, pointing out that sonic crystals reach insulation values comparable to the maximum Insertion Loss achievable due to the top edge diffraction.

Antoni JAROSZEWSKI, Andrzej RAKOWSKI

Statistical analysis of initial transients in the threshold Békésy tracings, observed mostly at higher rates of the signal level control (i.e. 10 dB /s and 30 dB /s), is given. The transients reach several dB and last about 10 s. Possible background of psychological nature is discussed.

François-Xavier Féron

First developed in the mid-1970s, spectral music represents one of the main genres of contemporary French music. In Périodes (1974) for 7 instruments, Gérard Grisey (1946-1998) sets the foundation of this new approach to music composition, which explores both the acoustical properties of sound and specific features of the auditory system. Gérard Grisey’s archives at the Paul Sacher Foundation in Basel contain, among other things, musical manuscripts (drafts, autograph notes, drawings, etc.) of each of the composer’s works, as well as manuscripts of his writings, lesson notes, and books from his library. An examination of these documents, in addition to information gained from interviews with some of the composer’s close friends, allow us to understand better how Grisey imagined, developed, and brought to fruition his spectral approach to composition. In this paper, we begin by describing the composer’s education and explore his particular investigation of musical acoustics between 1972 and 1974 by studying the work of Émile Leipp and Fritz Winckel. We then look closely at two models (the respiratory cycle and the harmonic spectrum built on an E1 fundamental) that lie at the heart of the piece and underscore both their structural and auditory influence. Finally, after conducting a detailed analysis of the last section of the piece where Grisey uses instruments to recreate a sound spectrum, we question the existence of a trombone’s spectrogram that the composer himself claims to have used as a model. Through this genetic study of Périodes, we seek, in general, to document the construction of the cycle entitled Les espaces acoustiques (1974-1985) considered emblematic of the spectral aesthetic.

Víctor Espinosa, Lucio Calise, Vicent D. Estruch et al.

L’acustica è alla base delle più importanti tecnologie nelle telecomunicazioni subacquee, nonché nel rilevamento e nella determinazione dei target acustici nei mezzi acquatici. Le misure a multi-frequenza sono lo strumento principale per l’identificazione selettiva delle specie marine e per la pesca sostenibile. Lo sviluppo di sistemi a larga banda larga e le tecniche basate su sonar multi-beam costituiscono l'attuale sfida per gli scienziati e gli sviluppatori. Al contempo, sistemi più semplici ed economicamente efficienti, come boe satellitari, sono in grado di offrire informazioni per il monitoraggio degli ecosistemi o l’individuazione di specie bersaglio nella pesca marittima. ------ Acoustics is the basics of the most important technologies for underwater telecommunication, as well as for target detection and identification in the aquatic media. Multiple frequency measurements are the key for species discrimination and open the door for sustainable fisheries. The development of wider broadband systems and quantitative multi-beam sonars and processing techniques constitute the present challenge for scientists and developers. In parallel, simpler and cost-efficient systems like satellite buoys can offer clue information for marine ecosystem monitoring or target species fisheries.

P. Regulska, A. Skumiel, A. Józefczak

The influence of magnetic field intensity and temperature on acustic and magnetic proprieties was considered. Measurements were conducted at an ultrasonic wave frequency of 3.6 MHz, by a pulse method using the MATEC apparatus. The direction of ultrasonic wave propagation was parallel to the direction of the external magnetic field. The magnetic field range was 10–150 kA/m. The studies were performed for a selected temperatures. The results of this experiments suggested that in magnetic fluids there are different effects connect with restructuring this fluids.

Jazarević Vladimir, Rašuo Boško

The sound which is generated from the aircraft during the take-off and landing is one of the main problems for the people who live in the areas near the airport. It is very important to allocate and accurately calculate acoustic sources generated from turbulent flow produced by the aerodynamics components of the aircraft. This is done in order to calculate inhomogeneous term of Helmholtz equation which serves as a prediction tool of sound propagation in the domain. It is used subgrid-scale stabilized (SGS) finite element method for solving incompressible Navier-Stokes equation which simulate turbulent flow. Afterwards is done double divergence of Litghill’s tensor in order to calculate acoustics sources. Further, the transformation from time domain to frequency domain is used with Direct Fourier Transform which leads to smaller memory usage and computational cost. The aim of the article is to show that previously mention method lead to better and richer representation of the spectrum of frequencies obtained from turbulent flow. Good representation of spectrum will give better inhomogeneous term of Helmholtz equation. Better prediction and calculation of acoustics sources will lead to reduction of sound generation through design of aerodynamics components on the aircraft.

Lévy Christophe, Linarès Georges, Bonastre Jean-François

<p/> <p>Speech recognition applications are known to require a significant amount of resources. However, embedded speech recognition only authorizes few KB of memory, few MIPS, and small amount of training data. In order to fit the resource constraints of embedded applications, an approach based on a semicontinuous HMM system using state-independent acoustic modelling is proposed. A transformation is computed and applied to the global model in order to obtain each HMM state-dependent probability density functions, authorizing to store only the transformation parameters. This approach is evaluated on two tasks: digit and voice-command recognition. A fast adaptation technique of acoustic models is also proposed. In order to significantly reduce computational costs, the adaptation is performed only on the global model (using related speaker recognition adaptation techniques) with no need for state-dependent data. The whole approach results in a relative gain of more than 20% compared to a basic HMM-based system fitting the constraints.</p>