Ahmed Al Fuwaires, Peter Lukacs, Don Pieris
et al.
Speed of sound (SoS) mapping provides quantitative and localised information about a material’s acoustic properties, allowing identification of spatial compositional changes. In biomedical applications, SoS variations can inform tissue characterisation or improve image reconstruction algorithms that typically assume a constant SoS. However, conventional time-of-flight (ToF) tomography methods remain computationally intensive. This study presents experimentally derived tomographic reconstructions of SoS maps of heterogeneous structures from all-optically acquired data using a convolutional neural network (CNN). The CNN, trained on simulated data, enables near real-time, high-quality tomographic reconstructions. The novelty of this work lies in the integration of a laser ultrasound (LU) data acquisition setup with a CNN-based reconstruction approach, demonstrating its potential for remote and flexible inspection of biomedically relevant samples. The CNN was trained using simulated data based on ultrasonic wave propagation models and achieved tomographic reconstructions of a 77 mm × 77 mm area in less than 6 ms. Data were acquired from four tissue-mimicking phantoms (30 mm diameter) with inclusions of varying size (minimum 6 mm diameter) and SoS (minimum variation 25 m/s). When compared with published, in vivo studies using mammography (MM), conventional ultrasound, and magnetic resonance imaging (MRI), the proposed method yielded 5.73% mean sizing error for phantoms and inclusions relative to the ground truth, highlighting the clinical potential of the LU-CNN framework and the need for further in vivo testing. These findings underscore the method’s potential as a precise, faster alternative to conventional imaging and reconstruction methods used in clinical practice.
Speech learning often occurs under adverse acoustic conditions, yet learned representations are later accessed in quiet. This study asked whether word learning acquired under background noise generalizes to quiet listening and whether generalization depends on training noise level. Sixty young adults trained within a 5-day pseudoword–picture association task under Quiet, +10 dB signal-to-noise ratio (SNR), or 0 dB SNR speech-shaped noise. Learning was assessed after each session using an identification task conducted in quiet. Accuracy improved across sessions in all groups. When tested in quiet, performance following +10 dB SNR training matched Quiet, whereas performance following 0 dB SNR training was lower. These findings suggest that generalization to quiet depends on training SNR, with robust transfer following moderate noise.
The potential utility of providing low-frequency portions of speech signals through vibrotactile stimulation as an aid to speech recognition by cochlear implant recipients was examined. Sixty-five young adults with normal hearing heard four-channel noise-vocoded sentences high-pass filtered above 0.25 kHz as well as those noise-vocoded sentences combined with the original signal filtered below 0.25 kHz, presented through either auditory stimulation or vibrotactile stimulation. Improved speech recognition was observed for both groups, but effects were smaller for participants in the vibrotactile group than for those in the auditory group. Future research efforts should explore ways of enhancing the vibrotactile signal.
Nadège Aoki, Benjamin Weiss, Youenn Jézéquel
et al.
Acoustic cues of healthy reefs are known to support critical settlement behaviors for one reef-building coral, but acoustic responses have not been demonstrated in additional species. Settlement of Favia fragum larvae in response to replayed coral reef soundscapes were observed by exposing larvae in aquaria and reef settings to playback sound treatments for 24–72 h. Settlement increased under 24 h sound treatments in both experiments. The results add to growing knowledge that acoustically mediated settlement may be widespread among stony corals with species-specific attributes, suggesting sound could be one tool employed to rehabilitate and build resilience within imperiled reef communities.
Eriberto Oliveira DO NASCIMENTO, Paulo Henrique Trombetta ZANNIN
This study evaluated the combined sensitivity analysis of several room acoustic descriptors: reverberation time (T30), center time (Ts), early decay time (EDT), definition (D50), clarity (C50), useful-to-detrimental sound ratio (U50), and speech transmission index (STI); and also it assessed how these descriptors responded jointly to different acoustic-structural factors. The first-order factors were background noise (A), acoustic ceiling tile sound absorption coefficient (B), confinement (C), and occupancy (D), along with their interaction effects. A novel method is proposed for this joint evaluation of sensitivity factors. This method involves in situ measurements and an unreplicated 2^4 factorial design, which has been validated by ODEON software. The significance of input factors is determined using artificial neural networks (ANN) and the modified profile method (MPM), validated by multiple linear regression (MLR). Three significant correlation groups are identified
at p < 0:05: group 1 (EDT, T30, Ts), group 2 (C50, D50), and group 3 (U50, STI). The ceiling material sound absorption (B) is found to affect reverberation (groups 1 and 2), while background noise (A) impacts STI and U50. A weak correlation is found between D50 and STI. These results are confirmed by the MLR and MPM methods.
Rizwan Ahmad, Muhammad Riaz, Mohammed Aldholmi
et al.
Background: Solanum pseudocapsicum (PC) and Capsicum annum (CA) belongs to the family of Solanaceae. CA have been reported a rich source of phenolics whereas, the phenolics content of GA (gallic acid), SC (scopoletin), RA (rosmarinic acid), and RV (resveratrol) are yet to be reported for the PC-fruit. This study comparatively evaluates the phenolics profile for different parts (seeds and skin) and colors (green and red) of the PC- and CA-fruits using the green solvents of ethanol (ET), acetone (AC), water (H2O), and different combinations of these solvents. Methodology: Ultrasonics extraction (US) and UHPLC analysis were employed for phenolics evaluation. Results: The USMD (method development) revealed the highest extract yield of 62 mg/100 mg for the PC-skin in ET:AC (70:30) solvent whereas, more phenolics (ppm) were observed for PC-seeds in ET:AC (50:50) solvent, particularly the SC (29.46) and GA (16.92). The UHPLCMDMV exhibited significant accuracies (100.70–114.14 %) with r2-values (0.9993–0.9997) in the linearity range of 1–200 ppm. The USMV (method validation) in PC- and CA-fruit parts and colors revealed more extract yields for the red skin part of the PC- (180.5 mg) and CA-fruit (126.2 mg). The phenolics were seen more in the green seeds of the PC-fruit (ppm); SC (276), GA (147.36), RV (28.54), and RA (23.87) followed by the green PC-skin, and red/green CA-seeds. The statistical models of mean differences, ANOVA, and Pearson’s correlation showed significant differences for the PC-fruit parts (seeds and skin) and colors (red and green) vs extract yield and phenolics content (P = 0.05). Conclusion: PC-and CA-fruits were successfully evaluated where the seeds for the green fruits exhibited more phenolics amount.
The subjective impression of the concert hall acoustics is usually formed around various descriptors, such as clarity and definition, and envelopment in the sound field. While room acoustics is evaluated from room impulse responses with several standardized objective parameters1, such as G, T60, C80, EDT, and LF, the frequency response of the hall is sometimes left for lesser importance. The overall frequency response commonly depends on the surface properties. Although the direct sound frequency response could be intuitively thought as flat, the "seat dip" phenomenon affects to the direct sound by attenuating low frequencies. The effect is noticed mainly around 100-300 Hz, but it can span up to 1000 Hz. The seat dip effect was first introduced with real and model measurements at different distances from the stage by Schultz and Watters, and Sessler and West in 19642,3. The attenuation was noticed at approximately one-quarter wavelengths of the seat heights, when the sound is diffracted from the seat backs to the floor, and later integrates with the actual direct sound causing destructive interference. The effect was observed to increase with longer receiving distances up to 19 m. Subsequently, multiple papers have been published on the subject with measured and experimental data.
Plate-type acoustic metamaterials (PAM) consist of a thin film with periodically added masses. These metamaterials can be designed to be very lightweight and exhibit narrow bands at low frequencies with high sound transmission loss values that can exceed the corresponding mass-law considerably. In this paper, a new approach for improving the bandwidth of PAM by using Helmholtz resonators which represent the added masses is investigated. The key principle of this design is that the Helmholtz resonance gives rise to an additional peak in the transmission loss spectrum which can be tuned to increase the bandwidth of the PAM. Sound transmission loss measurements of a large-scale test sample with 270 resonators are used to demonstrate the performance of the proposed metamaterial under diffuse field excitation. Then, numerical simulations based on the finite element method are used to further investigate the physical mechanisms of the PAM with Helmholtz resonators. It is shown that when the baseplates of the Helmholtz resonators are stiff enough, the Helmholtz resonance is decoupled from the vibro-acoustics of the PAM. This can be exploited to effectively increase the bandwidth of PAM without any significant reductions of the sound transmission loss due to coupling resonances.
Circular-array-based photoacoustic computed tomography (CA-PACT) is a promising imaging tool owing to its broad acoustic detection coverage and fidelity. However, CA-PACT suffers from poor image quality outside the focal zone along both elevational and lateral dimensions. To address this challenge, we proposed a novel reconstruction strategy by integrating the synthetic aperture focusing technique (SAFT) with the 2nd derivative-based back projection (2nd D-BP) algorithm to restore the image quality outside the focal zone along both the elevational and lateral axes. The proposed solution is a two-phase reconstruction scheme. In the first phase, with the assistance of an acoustic lens, we designed a circular array-based SAFT algorithm to restore the resolution and SNR along the elevational axis. The acoustic lens pushes the boundary of the upper limit of the SAFT scheme to achieve enhanced elevational resolution. In the second phase, we proposed a 2nd D-BP scheme to improve the lateral resolution and suppress noises in 3D imaging results. The 2nd D-BP strategy enhances the image quality along the lateral dimension by up-converting the high spatial frequencies of the object’s absorption pattern. We validated the effectiveness of the proposed strategy using both phantoms and in vivo human experiments. The experimental results demonstrated superior image quality (7-fold enhancement in elevational resolution, 3-fold enhancement in lateral resolution, and an 11-dB increase in SNR). This strategy provides a new paradigm in the PACT system as it significantly enhances the spatial resolution and imaging contrast in both the elevational and lateral dimensions while maintaining a large focal zone.
Hugo Scudino, Jonas T. Guimarães, Rafaella Silva Moura
et al.
Minas frescal cheese is extremely popular in Brazil, with high perishability and acceptability. Among emerging technologies, ultrasound stands out for its satisfactory results regarding microbiological safety and technological and sensory aspects. The combined mild temperature application, called thermosonication, can generate even more promising results. In this study, a high-intensity ultrasound system combined with thermal heating (TS, thermosonication) was applied for the treatment of raw milk to produce Minas Frescal cheese. US energy was delivered to raw milk samples using a probe operating at a 20 kHz of frequency and nominal power of 160, 400, and 640 W. The TS system was compared with conventional pasteurization (HTST, high-temperature short-time pasteurization) at 72 to 75 °C and 15 s. Soft cheeses were prepared with different samples: (a) raw milk (control), b) conventionally pasteurized milk (HTST), and c) TS treat milk in different nominal power (TS160, TS400, and TS640). The produced cheeses were evaluated for microbiological behavior, rheology, color parameters, and bioactive compounds. TS treatment in milk resulted in higher microbial inactivation and stability during storage, improved color parameters (higher lightness (L*), and whiteness index (WI). TS treatment also showed a higher generation of bioactive compounds (higher antioxidant, and inhibitory activities of α-amylase, α-glucosidase, and angiotensin-converting enzymes) than HTST. The impact of TS on rheological properties was similar to HTST, resulting in more brittle and less firm products than the cheese produced with raw milk. The positive effects were more prominent using a nominal power of 400 W (TS400). Therefore, TS proved to be a promising process for processing milk for Minas Frescal cheese production.
Couineaux Audrey, Ablitzer Frédéric, Gautier François
The cristal Baschet is a musical instrument created during the 1950’s by Bernard and Francois Baschet. It is composed of a large number of glass rods arranged in a chromatic scale. The sound produced results of vibrations induced by friction between wet fingers and the glass rods. Each glass rod is connected to an assembly of threaded shafts and a mass. Mechanical properties of this assembly determine the pitch of the note. Then vibrations are transmitted to large metal panels or cones that act as radiating elements. The manufacturing and tuning of this instrument is based on empirical knowledge and involves many parameters whose effects are not clearly understood. One of the encountered problems is the difficulty to produce sound in the high register of the instrument. In an attempt to understand the influences of these parameters on playability, a minimal physical model of the cristal Baschet is developed. It focuses on the interaction between the finger and the isolated resonator. The dynamic behavior is described by a set of modes obtained from a finite element model or from experimental modal analysis. The musician’s gesture is described by two control parameters: the velocity of the finger along the glass rod and the normal force applied by the finger on the rod. To describe the interaction between the finger and the resonator, a friction law is implemented. The influence of different parameters is studied by means of linear stability analysis and time-domain simulations. Specific criteria are developed to highlight the role of design parameters on playability.
Acoustics in engineering. Acoustical engineering, Acoustics. Sound
With the steady increase in the consumption of ultra-processed foods, there is growing interest in sustainable diets that include more plant protein. However, little information is available regarding the structural and functional properties of cactus (Opuntia ficus-indica) seed protein (CSP), a by-product of the cactus seed food-processing chain. This study aimed to explore the composition and nutritional value of CSP and reveal the effects of ultrasound treatment on protein quality. Protein chemical structure analysis showed that an appropriate intensity of ultrasound treatment (450 W) could significantly increase protein solubility (96.46 ± 2.07%) and surface hydrophobicity (13.76 ± 0.85 μg), decrease the content of T-SH (50.25 ± 0.79 μmol/g) and free-SH (8.60 ± 0.30 μmol/g), and enhance emulsification characteristics. Circular dichroism analysis further confirmed that the ultrasonic treatment increased the α-helix and random coil content. Amino acid analysis also suggested that ultrasound treatment (450 W) increased the hydrophobic amino acid content. To evaluate the impact of changes in the chemical structure, its digestion behavior was studied. The results showed that ultrasound treatment increased the release rate of free amino acids. Furthermore, nutritional analysis showed that the digestive products of CSP by ultrasound treatment can significantly enhance the intestinal permeability, increase the expression of ZO-1, Occludin and Claudin-1, thus repairing LPS induced intestinal barrier disfunction. Hence, CSP is a functional protein with high value, and ultrasound treatment is recommended. These findings provide new insights into the comprehensive utilization of cactus fruits.
High temporal resolution concentration measurements in rapid gas flows pose a serious challenge for most analytical instruments. The interaction of such flows with solid surfaces can generate excessive aero-acoustic noise making the application of the photoacoustic detection method seemingly impossible. Yet, the fully open photoacoustic cell (OC) has proven to be operable even when the measured gas flows through it at a velocity of several m/s. The OC is a slightly modified version of a previously introduced OC based on the excitation of a combined acoustic mode of a cylindrical resonator. The noise characteristics and analytical performance of the OC are tested in an anechoic room and under field conditions. Here we present the first successful application of a sampling-free OC for water vapor flux measurements.
Abstract Broadband sound absorption at low frequency with minimal space consumption and material cost is a trending research problem in engineering acoustics. Conventional sound absorbers like porous materials and microperforated panels (MPP) are not good enough to absorb sound in the low frequency regime. To enhance the acoustic performance, Helmholtz resonator with inserted neck (HRIN) is integrated with MPP in this investigation. The sound absorption characteristics of series and parallel arrangements of both MPP and multiple HRINs are theoretically modelled using electro-acoustic analogy and the results are compared with full field finite element simulations. Most importantly, it is observed that the parallel arrangement of MPP and multiple HRINs considerably reduced the thickness of the absorber. In addition, a single unit comprising four parallel Helmholtz resonators when arranged in conjunction with MPP absorbed more than 65% sound over a band width of 318 Hz to 880 Hz whereas the successive arrangement of the same unit with MPP is affected with high anti-resonance effect. It is demonstrated that, the proposed modelling strategy very well predicts the acoustic performance of HR integrated MPP absorbers on par with the computational intensive numerical simulations. Moreover, these configurations exhibited efficient low frequency sound absorption capability even with reduced absorber thickness.
In this paper, the acoustic pressure generated in the near field of a single stream cold jet is investigated. The analysis is focused on the effect of the initial conditions at the nozzle exit parametrized by considering two different turbulence levels and two different boundary layer thicknesses. The study has been performed by processing a numerical database obtained by large-eddy simulations (LES) of a jet flow at M = 0.9 and Re = 105. Pressure time series are obtained from pointwise virtual probes located in several radial and axial positions in the jet near-field. The acoustic pressure is extracted by the application of a consolidated wavelet-based procedure and the achieved acoustic signals are analyzed in terms of global quantities as well as by computing wavelet-reconstructed Fourier spectra. The results show that both the boundary-layer thickness and the turbulence level significantly affect the acoustic pressure in terms of its intensity and directivity whereas the distribution of energy in the frequency domain depends appreciably, only on the boundary-layer thickness.
Acoustics in engineering. Acoustical engineering, Acoustics. Sound
This research investigated the effect of ultrasound (US) pretreatment prior to spray drying on the powder flow and moisture sorption behaviour of micellar casein concentrate (MCC). MCC produced from skim milk microfiltration was sonicated at energy intensity of 0 (control), 47 J/mL (S-2000), 62 J/mL (S-3000) and 76 J/mL (S-4000). The results revealed that US pretreatment significantly increased the average particle size (D50) from 82.46 μm to 100.73 μm and reduced the surface fat content from 19.2% to 13.8%, resulting in decreased basic flow energy, cake energy and cohesion. Besides, the US treated samples showed relatively poor ability to acquire the moisture from the atmosphere than the control. Protein structure analysis showed that α-helix decreased with enhanced US power, while β-sheet and surface hydrophobicity increased, implying hydrophobic groups were exposed and water sorption rate was impeded. As a result, US pretreatment can improve the powder flow and potentially reduce the negative effect of cake formation at high humidity.
To improve the ride comfort of wheeled armored vehicles, air springs are used. To describe the vehicle motion more accurately, a nine-degree-of-freedom air suspension system for the whole vehicle was established, and its equations of motion were derived. Through theoretical analysis of the stiffness characteristics and forces on the air springs, the nonlinear restoring force was obtained as a cubic polynomial of the air spring displacement. The simulation results obtained by fitting the polynomial and radial basis function curves with MATLAB/Simulink software are consistent with the actual test results, thus verifying the correctness of the nonlinear air spring polynomial model. Finally, a fuzzy fractional order PI λ D μ controller is designed and simulated for the vehicle-seat-body model in terms of wheel dynamic load, suspension dynamic deflection, body acceleration, and other indicators. The simulation results show that the fuzzy fractional order PI λ D μ Proportion Integral Differential (PID) control strategy has better overall performance than the PID control strategy, fuzzy control strategy, and fuzzy PID control strategy.
Control engineering systems. Automatic machinery (General), Acoustics. Sound