Acoustic Response Research Articles

Chronic corticosterone exposure causes anxiety- and depression-related behaviors with altered gut microbial and brain metabolomic profiles in adult male C57BL/6J mice

Chronic exposure to glucocorticoids in response to long-term stress is thought to be a risk factor for major depression. Depression is associated with disturbances in the gut microbiota composition and peripheral and central energy metabolism. However, the relationship between chronic glucocorticoid exposure, the gut microbiota, and brain metabolism remains largely unknown. In this study, we first investigated the effects of chronic corticosterone exposure on various domains of behavior in adult male C57BL/6J mice treated with the glucocorticoid corticosterone to evaluate them as an animal model of depression. We then examined the gut microbial composition and brain and plasma metabolome in corticosterone-treated mice. Chronic corticosterone treatment resulted in reduced locomotor activity, increased anxiety-like and depression-related behaviors, decreased rotarod latency, reduced acoustic startle response, decreased social behavior, working memory deficits, impaired contextual fear memory, and enhanced cued fear memory. Chronic corticosterone treatment also altered the composition of gut microbiota, which has been reported to be associated with depression, such as increased abundance of Bifidobacterium, Turicibacter, and Corynebacterium and decreased abundance of Barnesiella. Metabolomic data revealed that long-term exposure to corticosterone led to a decrease in brain neurotransmitter metabolites, such as serotonin, 5-hydroxyindoleacetic acid, acetylcholine, and gamma-aminobutyric acid, as well as changes in betaine and methionine metabolism, as indicated by decreased levels of adenosine, dimethylglycine, choline, and methionine in the brain. These results indicate that mice treated with corticosterone have good face and construct validity as an animal model for studying anxiety and depression with altered gut microbial composition and brain metabolism, offering new insights into the neurobiological basis of depression arising from gut-brain axis dysfunction caused by prolonged exposure to excessive glucocorticoids.

Study on the influence of cement slurry viscosity on acoustic emission response and deformation characteristics of slurry-coal cemented body

In the process of grouting sealing, the cementation failure of slurry and coal interface exists in the gas extraction borehole, which leads to unstable and gas leakage in the sealing section and affects the efficient gas extraction in the borehole. In order to study the influence of slurry viscosity on the failure characteristics of slurry-coal cemented body, this paper explores the law of influence of slurry viscosity on the acoustic emission response characteristics and deformation characteristics of slurry-coal cemented body under uniaxial compression through laboratory tests, data analysis and quantitative research of image processing. The results show that: (1) Changing the slurry viscosity can achieve the strength control of the cemented body, which can be increased by up to 42.65 %. (2) In the process of uniaxial compression, the cementation structure of slurry-coal cemented body breaks down successively, and its proportion and strength lead to the distribution difference of AE signals and the fluctuation of b-value. Combined with the phase response characteristics of the two, the change of failure mode can be analyzed to provide a reliable evaluation of crack propagation in the cemented body. (3) The b-value of the sample of slurry-coal cemented body with high-viscosity slurry does not fluctuate significantly, and is relatively stable at a low level near 1.0. The results are helpful to promote the research and development of sealing materials and sealing technology.

Experimental study on acoustic and flame responses in an annular combustor under azimuthal force

This study investigates the flame dynamics of an annular combustor under various azimuthal acoustic forces. The experimental platform was applied to external azimuthal acoustic force through four loudspeakers installed on the wall outside the plenum. Experiments were conducted with an equivalence ratio of Ф = 0.71 and a combustion power of P = 9.5 kW. Therein, four loudspeakers were used to precisely control the acoustic pressure amplitude, spinning ratio, and spinning direction, which stimulated the first-order standing mode, spinning modes, and second-order standing mode acoustic mode of the plenum, respectively. Our analysis of flame dynamics and acoustic response characteristics was based on different azimuthal modes, combined with dynamic mode decomposition (DMD) of the flame image sequence and acoustic pressure signal. The results corroborate the consistency between the acoustic field quaternion analysis and the flame image sequence DMD results despite varied external forcing conditions. Specifically, the characteristics of the flame vary by the applied forces. Moreover, DMD results indicate that the flame structure of the eigenfrequency mode is asymmetrical in spinning modes and tilts in the direction of the pressure gradient.

Celsr3 drives development and connectivity of the acoustic startle hindbrain circuit.

In the developing brain, groups of neurons organize into functional circuits that direct diverse behaviors. One such behavior is the evolutionarily conserved acoustic startle response, which in zebrafish is mediated by a well-defined hindbrain circuit. While numerous molecular pathways that guide neurons to their synaptic partners have been identified, it is unclear if and to what extent distinct neuron populations in the startle circuit utilize shared molecular pathways to ensure coordinated development. Here, we show that the planar cell polarity (PCP)-associated atypical cadherins Celsr3 and Celsr2, as well as the Celsr binding partner Frizzled 3a/Fzd3a, are critical for axon guidance of two neuron types that form synapses with each other: the command-like neuron Mauthner cells that drive the acoustic startle escape response, and spiral fiber neurons which provide excitatory input to Mauthner cells. We find that Mauthner axon growth towards synaptic targets is vital for Mauthner survival. We also demonstrate that symmetric spiral fiber input to Mauthner cells is critical for escape direction, which is necessary to respond to directional threats. Moreover, we identify distinct roles for Celsr3 and Celsr2, as Celsr3 is required for startle circuit development while Celsr2 is dispensable, though Celsr2 can partially compensate for loss of Celsr3 in Mauthner cells. This contrasts with facial branchiomotor neuron migration in the hindbrain, which requires Celsr2 while we find that Celsr3 is dispensable. Combined, our data uncover critical and distinct roles for individual PCP components during assembly of the acoustic startle hindbrain circuit.

Ultrasound protein-copolymer microbubble library engineering through poly(vinylpyrrolidone-co-acrylic acid) structure

HypothesisWhile albumin-coated microbubbles are routine contrast agents for ultrasound imaging, their short duration of contrast enhancement limits their use, yet can be improved by incorporating protein-copolymer hybrids into microbubble shells. The incorporation of N-vinyl-2-pyrrolidone and acrylic acid copolymer (P(VP–AA)) has been shown to enhance the performance of bovine serum albumin (BSA)-coated microbubbles. However, the impact of the copolymer structural properties on key microbubble characteristics (i.e., concentration, mean diameter and acoustic response) remains poorly understood. Therefore, we hypothesize that the copolymer structure affects its capacity to form micelle-like nanoaggregates, protein-copolymer hybrids, and microbubble shells, ultimately influencing the physicochemical and acoustic properties of the microbubbles. ExperimentsHere we evaluate the production and performance of BSA@P(VP–AA) microbubbles synthesized using a series of P(VP–AA) copolymers with –C8H17 and –C18H37 end groups and molecular weight cutoffs between 3.5 and 15 kDa. Both simulation and experimental data demonstrate that interactions between BSA and the copolymers significantly influence the performance of the resulting microbubbles across the library of 60 formulations. FindingsThe introduction of –C8H17 terminated copolymers into microbubble shells resulted in up to 200-fold higher concentration, 7-fold greater acoustic response, and 5-fold longer ultrasound contrast enhancement compared to plain BSA microbubbles. The enhanced acoustic performance was sustained during in vivo cardiac ultrasound imaging, without altering liver accumulation after copolymer introduction. These findings underscore how optimizing copolymer structure (specifically the terminal end group and molecular weight) can tailor the formation and performance of protein-copolymer-coated microbubbles, offering valuable insights for designing ultrasound contrast agents.

Inverse problem-solving method applied to the acoustic characterisation of a thin film via the Debye series method (DSM)

ABSTRACT The study of the ultrasonic acoustic response of materials is of increasing interest for the characterisation of high-frequency applications. In this work, some elastic properties (acoustic velocity and acoustic attenuation) and some physical properties (thickness and density), together with the phase shift of the transducer, are estimated via one method. Scanning acoustic microscopy was performed via an innovative and different method using a high-frequency (50 MHz) planar wave transducer. In addition, the Debye series model (DSM) was used to model the acoustic response of the bilayer structure of the glass substrate and the resin‒epoxy sample. The inverse problem of estimating the acoustic parameters that results in a DSM reflected echo that matches the experimental signal is solved by proposing an innovative step-by-step curve fitting algorithm. The algorithm for solving the inverse problem is then optimised via relative mean square error (RMSE) curves, resulting in a robust method for assessing the uniqueness of the multiparameter solution.

Through the history of the acoustic response within the theatre of Taormina: From Greek and Roman periods to our days

The ancient theatre of Taormina is considered one of the most beautiful attractions of this town. Built on top of a cliff over the Mediterranean Sea, the spectators remain captured by the suggestions that this performance arts space can still inspire. Finished to be erected in the 3rd century BC, the theatre in Hellenistic period was provided with a small temple on the top centre of the cavea. Modified by Romans based on their requirements for spectacles, the organization of this ancient theatre was amplified with the creation of a double porticus supported by a columnade, and with the extension of the scenic building. After its desuse, some construction elements of the theatre were utilized to build new structures in town, provoking significant damage to the original shape. The spectacles that nowadays are conducted within the ancient theatre are many, executed especially over summer seasons. Acoustic measurements have been carried out inside the theatre to understand the acoustic response of the existing conditions. Starting from this scenario, the values of the main acoustic parameters have been compared with the digital reconstruction of the building at the Greek and Roman period. This research study highlights the difference in the acoustic response between these two scenarios and the existing conditions, and how the acoustics during the Roman period was the most suitable for musical performances.

Chemical and Acoustical Mixed-Mapping of Geological Materials from Laser-Induced Plasmas: A Comprehensive Approach to Differentiate Mineral Phases.

The acoustic wave produced alongside laser-induced plasmas can be used in conjunction with the recorded atomic spectra of plasma emission to expand the physicochemical information acquired from a single inspection event. Among the most interesting uses of acoustic information is the differentiation of mineral phases with similar optical responses coexisting in geological targets. In addition, laser-induced plasma acoustics (LIPAc) can provide data related to the inspected material's hardness, density, and compactness. In this paper, we present a dual acoustic-optic laser-based strategy for the generation of high-resolution surface images of mineral samples. By combining simultaneous multimodal LIBS (laser-induced breakdown spectroscopy) and LIPAc spectral data from laser-induced plasmas, we explore the mineralogical composition of rocks embedded in resin matrixes to distinguish their chemical composition as well as their crystal phases based on physical changes caused by the different spatial arrangements of the constituent atoms. The multispectral polyhedron created by merging singular optical maps, one per detected elements, and the coincidental acoustic map enhance the distinction between regions present within the matrix of a host rock as compared to the differentiation yielded by each technique when used separately. The chemical information guides the composition of the mineral phases in the host rock. Then, the physical information obtained from acoustics may reinforce the identification of the detected mineral phase, draw the geological history of the inspected section, and showcase possible transformations, mainly of polymorphic nature. To test the combination proposed herein, we also inspected a septarian nodule featuring an ensemble of mineral phases with different origins. Mixed optical and acoustic responses from laser-produced plasmas of this complex sample allowed us to obtain more specific information. This approach constitutes a reliable and high-throughput tool for studying the surface of geological samples, which can substantially supplement well-established techniques for mineralogical analysis such as Raman spectroscopy and X-ray diffraction.

ATP-gated P2x7 receptor is a major channel type at type II auditory nerves and required for hearing sensitivity efferent controlling and noise protection.

Hearing sensitivity and noise protection are mediated and determined by negative feedback of the cochlear efferent system. Type II auditory nerves (ANs) innervate outer hair cells (OHCs) in the cochlea and provide an input to this efferent control. However, little is known about underlying channel information. Here, we report that ATP-gated P2x7 receptor had a predominant expression at type II ANs and the synaptic areas under inner hair cells and OHCs with lateral and medial olivocochlear efferent nerves. Knockout (KO) of P2x7 increased hearing sensitivity with enhanced acoustic startle response (ASR), auditory brainstem response (ABR), and cochlear microphonics (CM) by increasing OHC electromotility, an active cochlear amplifier in mammals. P2x7 KO also increased susceptibility to noise. Middle level noise exposure could impair active cochlear mechanics resulting in permanent hearing loss in P2x7 KO mice. These data demonstrate that P2x7 receptors have a critical role in type II AN function and the cochlear efferent system to control hearing sensitivity; deficiency of P2x7 receptors can impair the cochlear efferent suppression leading to hearing oversensitivity and susceptibility to noise.

Burner and Flame Transfer Matrices of Jet-Stabilized Flames: Influence of Jet Velocity and Fuel Properties

Abstract To achieve the decarbonization of electrical power generation, gas turbines need to be upgraded to combust high-hydrogen content fuels reliably. One of the main challenges in this upgrade is the burner design. A promising burner concept for a high-hydrogen fuel mixture are jet burners, which are highly flashback resistant thanks to their high bulk velocity. Due to its nonacoustically compact extension and the presence of hydrogen in the fuel mixture, new challenges arise in assessing the (thermo)acoustic response of this burner design. A burner transfer matrix (BTM) and the flame transfer function (FTF) or transfer matrix (FTM) are typically measured with the multimicrophone method (MMM) to assess the performance of new burner types in relation to thermoacoustic stability. With the switch toward hydrogen, the fuel/air mixture is significantly altered in its properties regarding the speed of sound and density, which are of fundamental importance for acoustic waves propagation and their reconstruction via the MMM, as highlighted in recent work. In this work, we extend this discussion by studying the influence of the gas composition within the burner when measuring BTMs, and its indirect effect on the assessment of FTFs. Experimentally, we achieve this by adapting the preheating temperature during the measurement of the BTM with a nonreactive mixture in order to match the speed of sound of the hydrogen–air mixture required to flow in the burner under reactive conditions. Additionally, we present an analytical model for the jet burner transfer matrix, which is validated against the experimental data. Since the BTM is fundamental for the assessment of the FTM and FTF, the propagation of the error of changing fuel mixtures in the burner is evaluated. The influence of the variation in reactant composition of the BTM on the FTM assessment is noticeable, particularly in the gain of the FTFs. Furthermore, the influence of the total mass flow and, thus, the bulk flow velocity on the FTF is analyzed.

Examining perfluorohexane sulfonate (PFHxS) impacts on sensorimotor and circadian rhythm development.

Perfluorohexane sulfonate (PFHxS) is a ubiquitous perfluoroalkyl substance known for its environmental persistence and potential toxicity. This study investigated PFHxS's impact on zebrafish embryos, focusing on sensorimotor behavior, circadian rhythm disruption, and underlying molecular mechanisms. Under 24 hr dark incubations, PFHxS exposure induced concentration-dependent hyperactivity within larval photomotor response, characterized by the distinctive "O-bend" response, strong light-phase hyperactive movement and seizure-like movements. It appears that PFHxS-treated embryos cannot sense light cues in a normal manner. Similar hyperactivity was seen for acoustic startle response assay, suggesting that the response is not merely visual, but sensorimotor. LC-MS studies confirmed detectable uptake of PFHxS into embryos. We then conducted mRNA-sequencing across multiple time points (48 and 120 hpf) and concentrations (0.00025, 0.0025 and 25 µM). Data at the 25 µM (2-120 hpf) exposure showed disrupted pathways associated with DNA and cell cycle. Interestingly, data at 0.00025 µM - an environmentally relevant concentration- at 48 hpf showed disruption of MAPK and other signaling pathways. Immunohistochemistry of eyes showed reduced retinal stem cell proliferation, consistent with observed DNA replication pathway disruptions. To assess if these impacts were driven by circadian rhythm development, we manipulated light/dark cycles during PFHxS incubation; this manipulation altered behavioral patterns, implicating circadian rhythm modulation as a target of PFHxS. Since circadian rhythm is modulated by the pineal gland, we ablated the gland using metronidazole; this ablation partially rescued hyperactivity, indicating the gland's role in driving the phenotype. Collectively, these findings underscore proclivity of PFHxS to cause neurodevelopmental toxicity, necessitating further mechanistic exploration and environmental health assessments.

Design of lightweight aircraft trim panel with a high sound transmission loss

The trim panels of aircraft cabin are frequently made up of multilayer materials including a honeycomb, typically in the form of sandwich panels, which have the advantage of being lightweight and space-saving, but lack good acoustic insulation. It has been shown that, for 10% more mass, weights arranged in a fractal pattern in the honeycomb affect the vibratory pattern of a sandwich panel by creating multiple reflections of the bending waves on the inclusions. They thus generate a phenomenon of focusing vibratory waves providing localized modes while attenuating the structure's acoustic radiation. The objectives of this paper are to describe: first, the vibro-acoustic model of an overloaded homogenized bending panel (to mimic a trim panel with a fractal pattern); second, the physical phenomena associated to this concept; third, the impact on the modal behavior and the vibratory and acoustic responses.

Acoustics and vibration based milling diagnostics using supervised machine learning approaches

In industrial machining processes, tool failures may result in losses in surface and dimensional accuracy of a finished part, or possible damage to both the work piece and the machine. Consequently, tool condition monitoring has become essential to achieve high-quality machining as well as cost-effective production. Moreover, cutting tool degradation may vary considerably under different operation conditions and materials behaviour. Therefore, real time identification of the tool state during machining is critical. In this study the acoustic and vibration responses of the cutting tool and of the workpiece material are measured with the help of a microphone and a piezoelectric accelerometer. Many milling experiments were conducted for different conditions and tool failures, from which features were calculated in time and frequency domains and then split into two groups: 80% for the machine learning model training, 20% for the test phase. Then several supervised machine learning approaches have been applied and compared. Results of our study are implemented in a real tool wear predictive maintenance framework.

Design of a new low-noise pavement

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

Aeroacoustic analysis of flow induced resonance in a gas pipeline

Flow induced noise and vibration in the pipework of gas production platforms can lead to fatigue failures of attached small-bore pipes, and this can constrain the operating conditions of the platform. Typically such problems comprise a source of turbulence in the flow, an aeroacoustic feedback mechanism due to acoustic resonances inside the pipework, and mechanical resonances which amplify the resulting vibration. The problem described here occurred in the gas metering system of the platform, with the source located in the header which comprised a bifurcation into two metering lines and a number of sharp bends. Because of the cost of rectifying the problem an in-depth study was carried out to analyse the flow and induct acoustic conditions. The predictions will support recommendations for an efficient redesign of the entire system to control the problem at source. Various levels of CFD modelling (RANS and URANS) were carried out using the Openfoam code to predict the exact location and mechanism of the vortex shedding. The acoustic response of the complex ductwork was then modelled using the ACTRAN code to understand the feedback mechanism which led to resonance and high levels of response.

Acoustics response of granular porous material: experiment and modeling

Granular porous materials such as activated carbon have drawn increasing attention due to their good sound absorption performance at low frequency. However, some unique acoustical behaviors have been observed during sound absorption measurements of granular porous materials in impedance tubes: e.g., circumferential edge-constraint effects, level-dependent absorption behavior, and time-dependent absorption behavior. In order to explain these observations, a 1-dimensional poro-elastic model was first applied to describe the sound propagation in granules stacked in a cylindrical sample holder, as in a standing wave tube. Then this model was extended to a 2-dimensional finite difference (2DFD) model with depth-dependent stiffness of the granule stack considered by combining Janssen's model and Hertzian contact theory. The 2DFD model was validated with the measurements of the granular porous materials, and it was found that the 2DFD model is a powerful tool to analyze the acoustic response of granular porous material, thus providing a means of characterizing the granular materials. In the present work, the above-mentioned experimental observations and the 2DFD model are introduced, and the experiment results are analyzed with the 2DFD model. Finally some future work on granular porous materials is introduced.

Assessment of the effectiveness of ship machinery noise reduction measures using a test platform in a water basin

Underwater radiated noise (URN) from commercial shipping is partly responsible for increased ocean ambient noise levels in the last decades. To preserve marine wildlife, there is a need to reduce it. Machinery noise is the dominant URN source at lower speeds. Mitigation technologies exist to reduce it, but a lack of quantitative data regarding their effectiveness results in limited practical ship applications since the cost-to-benefit ratio is imprecise. A small ship-like structure (test platform) representative of a ship section is designed and constructed to conduct measurements in a controlled environment and at a lower cost than actual on-ship testing. The platform is deployed in a water basin whose acoustic response is first characterized by reverberation measurements. Vibroacoustic sources simulate structure-borne and airborne noise, while hydrophones and sensors measure the response in the water basin and of the platform. Measurements with and without standard mitigation technologies installed in the platform are conducted to quantify the insertion loss. Up to 37 and 20 dB URN reductions are obtained with elastic mounts and mineral wool, respectively. The results obtained with the platform and the developed methodology can support and guide the implementation of mitigation measures in current and future ship constructions.

Automated Classification of Egg Freshness Using Acoustic Signals and Convolutional Neural Networks

Abstract The acoustic response of eggs has not been fully optimized for quality detection purposes. This research investigates the utilization of acoustic response as input features for classifying fresh and rotten eggs using Convolutional Neural Networks (CNN). Acoustic measurements were conducted using an experimental setup involving a striking rod, microphone, and microcontroller to capture acoustic responses from eggs struck vertically and horizontally. Features such as energy, entropy, zero crossing rate, spectral centroid, and Mel Frequency Cepstral Coefficients (MFCC) were extracted from the recorded acoustic signals. The study utilized a sample set of 200 intact chicken eggs without cracks, equally split between fresh and rotten eggs. Principal Component Analysis (PCA) revealed significant differences in acoustic responses between fresh and rotten eggs, with clear separation observed in horizontal measurements. Three primary classification models—Convolutional Neural Network (CNN), Deep Neural Network (DNN), and Support Vector Machines (SVM)—were evaluated for this classification task. In vertical tapping, CNN and DNN demonstrated stable performance with approximately 85% accuracy, while SVM slightly trailed with around 80% accuracy. However, in horizontal tapping, all three models achieved perfect classification with accuracy, precision, recall, and F1-score reaching 100%. This study demonstrates the effective use of acoustic response as input for Deep Learning models to distinguish between fresh and rotten eggs. The findings highlight the potential application of this technology in the food industry to ensure product quality before consumption, with significant implications for developing reliable automated solutions. Future research could expand validation using larger datasets and optimize sensor usage and data processing techniques to enhance detection consistency and reliability.

Modeling and simulation study of acoustic response for dual-membrane capacitive MEMS microphone

Abstract As the micro-electro-mechanical systems (MEMS) technology matures, MEMS sensors have found widespread applications in mechatronics, robotics, and voice control. The high stability, high integration, and radio frequency interference resistance of MEMS microphones have rapidly led to their adoption in these domains, displacing electret condenser microphones.This article focuses on modeling and analyzing dual-membrane capacitive MEMS microphone, utilizing an lumped equivalent circuit model to calculate the microphone’s acoustic frequency response. Furthermore, the article employs the finite element method (FEM) to conduct a detailed analysis of the resonant frequency of the membrane, as well as to explore the effects of changes in the volume of the front and back chamber on the packaging performance of MEMS microphones. Finally, physical tests were conducted, and the simulation results of the two models showed considerable consistency with the curves obtained from the physical tests, verifying the accuracy of the models.

Replayed reef sounds induce settlement of Favia fragum coral larvae in aquaria and field environmentsa).

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.