Abstract:

We propose a non-associative reformulation of quantum electrodynamics (QED) based on octonionic and sedenionic hypercomplex algebras, replacing the conventional associative Clifford algebra and Dirac gamma matrices. In this framework, the associator — a quantity that vanishes in standard QED — becomes physically active, inducing Yukawa-type screening and regulating self-energy divergences. This removes the need for renormalization and resolves the vacuum catastrophe. Lepton masses arise algebraically from associator norms without invoking the Higgs mechanism, yielding accurate predictions for the electron, muon, and tau masses. Likewise, anomalous magnetic moments (g-2)/2 for all three charged leptons emerge naturally from generation-dependent associator corrections, matching experimental values to high precision — including the muon anomaly — without perturbative loop corrections. The model introduces gauge fields valued in non-associative algebras and generalizes the field strength tensor to include commutators and associators. This results in a divergence-free, highly predictive quantum field theory with no adjustable parameters. Our results suggest that non-associativity provides a deeper algebraic foundation for quantum dynamics, encoding mass, anomaly, and vacuum structure in a unified formalism.

Abstract: Accurate determination of the target strength (TS) of a fish species is essential for estimating the biomass of fish stocks using acoustic technology. This study estimated the daytime in situ target strength of Pacific hake (Merluccius productus) at 38 kHz using echosounder data collected during hake biomass acoustic trawl surveys and research cruises conducted from 2009 to 2019 by U.S. and Canadian scientists. The intercept term for the 20-log TS regression over fish length at 38 kHz, b_20, was found to be -67.9 dB re 1 m2 (CI: -68.09, -67.72) closely aligning with the currently used value of -68 dB in biomass assessments. Applying the revised b_20 value of -67.9 dB in past stock assessments suggests that biomass estimates would be underestimated by less than 3%, which is well within the typical uncertainty range of fish stock assessments.

Abstract: Consumers expect snacks that are tasty, healthy, and crunchy. However, optimizing crunchiness using sensory methods is time-consuming and expensive. Therefore, this paper proposes a new approach to measuring instrumental crunchiness. Whole strawberries of the "Honeoya" variety were osmotic dehydrated in a solution of sucrose and chokeberry juice concentrate for 1, 2, and 3 hours before freeze-drying. Texture was measured using acoustic emission (AE) and a compression test. The crunchiness index was calculated taking into account the number of AE events and mechanical energy. The content of bioactive substances, water activity, and porosity of the freeze-dried products were also assessed. Freeze-dried fruits after dehydration in chokeberry juice concentrate were characterized by lower final water activity and higher content of bioactive substances, but their crunchiness was the lowest. The crunchiest, loudest, and least hard were freeze-dried strawberries, dehydrated in a sucrose solution. The tested freeze-dried strawberries differed in the range of sound frequencies generated, which indicates a different cracking mechanism.

Abstract: This study aims to examine the effects of noise levels in the design studio of the De-partment of Interior Architecture and Environmental Design at Afyon Kocatepe Uni-versity on students. Noise levels were measured at different times and locations within the studio environment. To assess the impact of these noise levels on students, a survey was administered to gauge their perceptions of noise. The survey questions assessed students' perceptions of noise levels and noise diversity in design studios in terms of discomfort, difficulty concentrating, communication difficulties, and overall producti-vity. According to the results, the majority of students stated that the noise in the stu-dio distracted them and reduced their productivity. The noise level measurement re-sults also supported these perceptions, showing that the limit values were exceeded most of the time. In this regard, design solutions such as spatial partitions, fab-ric-covered panels, sound-absorbing vinyl flooring, and acoustic ceiling elements were proposed to reduce noise in studio 130. In this context, the goal is to create a more effi-cient and comfortable learning environment for design studios where students need to maintain high levels of motivation and concentration while working on projects.

Abstract: The study focuses on the implementation of flow rate sensing and measurement in smart inhalers for the effective management of respiratory diseases. It highlights the importance of adhering to proper inhalation techniques and maintaining consistency for managing respiratory conditions. Methods and relevant commercial and prototype research-type devices for sensing and measuring inhalation flow rate in smart inhalers are evaluated and compared. The findings show that the utilisation of acoustic analysis combined with air-pressure sensing is a promising approach to detect and assess the inhaling action, ultimately allowing for improvement in treatment outcomes and quality of life for patients with respiratory diseases.

Abstract: A mathematical model of high-frequency geoacoustic emission for a single dislocation radiation source is suggested in the papper. The mathematical model is a linear Berlage oscillator with non-constant coefficients whose solution is the Berlage function momentum. Further, the values of the parameters of the Berlage pulse are specified using experimental data. For this purpose, the problem of multidimensional optimization is solved, which consists of two stages: global optimization using the differential evolution method and local optimization according to the Nelder-Mead method. Statistics are given to confirm the correctness of the obtained results: standard error and coefficient of determination. It is shown that two-stage multivariate optimization makes it possible to refine the parameters of the Berlage pulse with a sufficiently high accuracy to describe high-frequency geoacoustic emission.

Abstract: The purpose of this study is to investigate the potential for estimation of soil porosity and pore size (key indicators of soil physical health) using the strength of reflection of audio pulses from natural soil surfaces. The motivation for this work is the importance of productive and healthy soils in agriculture and other economic uses of land depending on plant growth. Soil porosity and pore structure are also significant in a wide range of environmental impacts such surface water runoff, and greenhouse gas exchanges. Methods exist for evaluating soil porosity in a laboratory environment or by inserting sensors into the soil in the field. However, no convenient non-contact in situ measurement method exists. This means that existing soil evaluations do not generally sample adequately in either space or time. In the current study we develop a new methodology based on reflection of audio pulses in the frequency range 4 to 16 kHz. Such pulses are readily generated by, and analyzed with, for example, a mobile phone. The key to this very new method is a Taylor series expansion of the functional form of the acoustic reflectivity in a way that includes, embedded as simple linear regression coefficients, in a way which allows three soil parameters (porosity, tortuosity, and average pore radius) to be easily estimated. The requirements to set up these regressions are to generate pulses at a number of audio frequencies and a number of angles of incidence to the ground surface. More than 3 million Monte Carlo simulations are performed using known random noise levels from the proposed sensor system. The simulation results show that both the systematic and random errors in estimation are very small, being typically less than 1 % for all three soil parameters. All assumptions and sources of error related to this method are discussed (to the best of the authors’ knowledge) and it is concluded that a practical new operational tool should be able to be readily manufactured and validated. This tool will be inexpensive, compact, low-power, non-intrusive to either the soil or the surrounding environment and will readily be incorporated into mobile phones as a fast and accurate means of visualizing farm-scale soil health.

Abstract: We present a novel formulation of the Rayleigh–Plesset equation to describe stable gas bubble dynamics in viscoelastic media, using bubble volume variation, rather than radius, as the primary variable of the resulting nonlinear ordinary differential equation. This formulation incorporates the linear Kelvin–Voigt model as the constitutive relation for the surrounding fluid, capturing both viscous and elastic contributions, to track the oscillations of a gas bubble subjected to an ultrasonic field over time. The proposed model is solved numerically and validated by comparison with theoretical results from the literature. We systematically investigate the nonlinear oscillations of a single spherical gas bubble in various viscoelastic environments, each modeled with varying levels of rheological complexity. The influence of medium properties, specifically shear elasticity and viscosity, is examined in detail across both linear and nonlinear regimes. This work improves our understanding of stable cavitation dynamics by emphasizing key differences from Newtonian fluid behavior, resonance frequency, phase-shifts and oscillation damping. Elasticity has a pronounced effect in low-viscosity media, whereas viscosity emerges as the dominant factor modulating the amplitude of oscillations in both the linear and nonlinear regimes. The model equation developed here provides a robust tool for analyzing how viscoelastic properties affect bubble dynamics, contributing to improved prediction and control of stable cavitation phenomena in complex media.

Abstract: This study presents a comparative analysis of a "design" speaker cabinet shape and a conventional block enclosure, both having identical internal volumes. Both enclosures were built from birch wood, and for comparison, block-shaped baffles were also made from medium-density fiberboard (MDF). While the designer's new shape was hand-crafted using a lathe and a cube baffle on a CNC machine. The block-shaped sound box was made as a representative of the classic shape that occurs most often in the world of music. For this reason, it is offered as an ideal reference sample of the enclosure for comparison with the new design proposal, which was produced based on the shape predispositions and the interest of potential customers. The loudspeaker systems were then subjected to anechoic chamber testing using the sine sweep technique to assess and compare their resonance characteristics. The box-shaped enclosure showed a smoother course of the frequency response, but the differences are not significant. A potential improvement in acoustic performance was offered by acoustic dampening material that was incorporated into each enclosure, and the measurement was repeated. With the acoustic filling, the frequency curves are even more smoothed, and it can be said that the damping material can eliminate some of the imperfections of the enclosures.

Abstract: A previous analysis of Antarctic acoustic data relevant to quantifying frazil contributions to sea ice accretion is reconsidered to address inconsistencies with river frazil results acquired with similar instrumentation but augmented to suppress instrument icing. It was found that sound attenuation by consequent icing limited credible Antarctic acoustic frazil measurements to afternoon and early evening periods which are show to encompass daily minimums in frazil production. This reality was masked by use of an unvalidated liquid oblate spheroidal frazil characterization model which greatly overestimated frazil concentrations. Much lower frazil contents were derived for these periods using a robust 2-frequency characterization algorithm which incorporated a validated, alternative, theory of scattering by elastic solid spheres. Physical arguments based on these results and instrument depth data were strongly suggestive of maximal but, currently, unquantified frazil presences during unanalyzed heavily-iced late evening and morning time periods.

Abstract: In recent years, defect detection based on ultrasound B-scan images has been widely utilized in industry to detect the quality and presence of defects in products. However, there are still some difficulties in the process of processing B-scan images, such as sampling noise, huge amount of data and so on. In this paper, we analyse the acoustic characteristics of ultrasound B-scan image time series, design an image preprocessing method to make the image information gray-scale lossless, and propose a screening method for ultrasound B-scan image segments containing defects based on the theory of image entropy and recurrence diagram. Comparison experiments between this method and the traditional image entropy screening algorithm show that this method can solve the above difficulties to a certain extent and has its own superiority. The method proposed in this paper provides a new idea for processing ultrasound B-scan image sequences, and presents a new choice when the traditional method is in limitation.

Abstract: We used an optomechanical microphone to measure the acoustic signals emitted by compressed-air jets emanating from apertures as small as ~ 5 um. In keeping with the predictions of aeroacoustic theory, spectra extending into the high-frequency (MHz) ultrasound region were observed. Most of this acoustic energy lies well above the range of a conventional ultrasonic microphone. Conversely, the broadband response of the optomechanical sensor offers the potential to localize and quantify leaks based on a more complete knowledge of the acoustic spectrum. We show that the minimum detectable flow rate, set by the onset of turbulence, scales with the hole size and was as low as ~ 10^-3 Pa·m^3·s^-1 for the smallest holes studied here. The results demonstrate that a sufficiently broadband and sensitive microphone might enhance the utility of ‘acoustic sniffer’ tools for quantitative gas leak detection.

Abstract: Addressing the limitations of restricted coding capacity and material dependency in acoustic identity tags for autonomous underwater vehicles (AUVs), this study intro-duces a novel passive acoustic identification tag (AID) design based on multilayered elastic cylindrical shells. By developing a Normal Mode Series (NMS) analytical model and validating it through finite element method (FEM) simulations, the work elucidates how material layering strategies regulate far-field target strength (TS) and establishes a time-domain multi-peak echo-based encoding framework. Results demonstrate that optimizing material impedance contrasts achieves 99% detection success at a 3dB sig-nal-to-noise ratio. Jaccard similarity analysis of 3,570 material combinations reveals a system-wide average recognition error rate of 0.41%, confirming robust encoding reli-ability. The solution enables combinatorial expansion of coding capacity with structural layers, yielding 210, 840, and 2,520 unique codes for 3-, 4-, and 5-layer configurations, respectively. These findings validate a scalable, hull-integrated acoustic identification system that overcomes material constraints while providing high-capacity encoding for compact AUVs, significantly advancing underwater acoustic tagging technologies through physics-driven design and systematic performance validation.

Abstract: The aim of the Italian Integrated Environmental Research Infrastructures System (ITINERIS) project is to establish the Italian Hub of Research Infrastructures within the environmental scientific domain. ITINERIS seeks to facilitate the observation and investigation of environmental processes across the atmosphere, marine domain, terrestrial biosphere, and geosphere. The project also endeavors to promote sustainable, cross-disciplinary research by leveraging existing data and services, emphasizing accessibility for users. The cornerstone of this initiative is the creation of the ITINERIS HUB, designed to provide users with seamless access to data and services. Notably, ITINERIS opts for the optimization and harmonization of existing data centers rather than creating new ones. The project will fortify these centers through various activities, with a particular focus on enhancing the Findable, Accessible, Interoperable, and Reusable paradigm across all participating entities. This contribution highlights the role of Laboratori Nazionali del Sud of Istituto Nazionale di Fisica Nucleare in the project. LNS is leading the Italian Ocean Sound sub-system in the contest of the marine domain of ITINERIS. An overview on the acoustic data acquisition chain and storage will be reported, with a particular insight into the use of high-sensitivity and large band-width hydrophones installed on the mooring station of LNS for real-time and long-term data capture. Hydrophones’ data are continuously transmitted to shore and analyzed. A selection of raw data and sound pressure levels in third-octave bands are calculated and stored to study the soundscape at the site.

Abstract:

In this paper, we developed our own software that can analyze piano performance by utilizing short-time Fourier transform, non-negative matrix decomposition, and root mean square. In addition, for the reliability of the developed software, we provided results reflecting the characteristics of various performers and signal analysis. In conclusion, it shows the possibility that musical flow and waveform analysis can be visually interpreted in various ways. Based on this, we were also able to derive an additional approach suitable for designing the system to seamlessly connect hearing and vision.

Abstract:

Introducing vegetation is an effective strategy for improving air quality and mitigating the heat island effect. Green façades, which consist of modules that support substrates and various plant species, integrate these elements. This study analyzes the acoustic absorption properties of a specific green wall module using an impedance gun and the Scan and Paint method for laboratory and on-site measurements. The impedance gun method is effective for in-situ analysis, offering advantages over standardized techniques for inhomogeneous samples. We measured the sound absorption coefficient of the substrate and the effects of different plant species. Key findings reveal that the substrate primarily influences sound absorption, with its coefficient increasing with frequency, similar to porous materials Vegetation enhances acoustic absorption of the substrate, depending on coverage and thickness, with 80-90% of absorption attributed to the substrate and 4-20% to vegetation. However, not all dense plant species improve absorption; some configurations may decrease it. Improvement correlates with substrate coverage and vegetation layer thickness, while the impact of plant morphology remains unclear. These findings confirm vegetation's potential as an acoustic absorption tool in urban settings. Additionally, green walls can enhance acoustic comfort in indoor environments such as offices and schools by reducing reverberation. They also improve air quality and provide aesthetic appeal, making them a multifunctional solution for modern architecture.

Abstract: We do not know how the earliest musical instruments -such as idiophones and aerophones- were played, but their acoustic properties can provide valuable clues. As a first step, we present here dissonance curves for a sound of a given spectrum. These curves show the relative dissonance that results for all intervals of a given instrument. This then leads to the association of spectra and scales, which are related because the dissonance curve has minima in the intervals that define the scale. A computational method for calculating dissonance curves is presented and several examples of its use in practical cases, both for Western and Eastern musical instruments, are given and interpreted. These results allow us to explain from a physical point of view the existence of well-known modern twelve note scales, as well as some uncommon but documented scales for various instruments in early musical history.

Abstract: This study presents a novel approach to remote speech recognition using a millimeter- 7wave micro-Doppler radar system operating at 94 GHz. The proposed method uses high-frequency 8radar to detect subtle speech-related vibrations, enabling speech recognition that is both non-contact 9and privacy-preserving. Tests with actual human speech followed initial experiments in which a 10piezoelectric crystal was used to simulate vocal cord vibrations. Radar returns were processed using 11state-of-the-art signal processing techniques, including short-time Fourier transform (STFT), to 12generate spectrograms and reconstruct speech signals. The system demonstrated high accuracy in 13speech reconstruction, with a strong correlation between the radar-reconstructed audio and the 14original speech signals. Cross-correlation analysis quantitatively confirmed the similarity between 15the reconstructed and original audio. These results validate the system's effectiveness in detecting 16and characterizing speech-related vibrations without direct audio recording. The findings support 17this innovative approach, with significant implications for applications in security, surveillance, and 18assistive technologies where privacy-preserving solutions are essential. Future research will focus 19on diverse real-world scenarios and further integration of advanced signal processing and machine 20learning techniques to enhance accuracy and robustness.

Abstract: A simple pore microstructure of parallel, identical, inclined smooth walled slits in a rigid solid, for which prediction of its geometrical and acoustic properties is straightforward, can yield useful sound absorption. This microstructure should be relatively amenable to 3D printing. Discrepancies between measurements and predictions of normal incidence sound absorption spectra of 3D printed vertical and slanted slit pore samples have been attributed to the rough surfaces of the slit walls and uneven slit cross sections perpendicular to the printing direction. Theories for the influence of (a) sinusoidal walls and (b) periodically varying uniform slit widths on the normal incidence absorption spectra of a slit pore medium are outlined. Although the slit wall surface and geometrical imperfections due to 3D printing differ from these idealizations, predictions assuming the ideal forms of roughness confirm that pore wall roughness could account for differences between predictions and data. Pore wall roughness is predicted to increase both flow resistivity and tortuosity thereby increasing the low frequency sound absorption of thin hard-backed layers. The extent to which sinusoidal slit walls or periodically varying uniform slit widths could improve sound absorption is explored.

Abstract: In this paper we demonstrate that torsional surface elastic waves can propagate along the curved surface of a metamaterial elastic rod (cylinder) embedded in a conventional elastic medium. The crucial parameter of the metamaterial rod is its elastic compliance which varies as a function of frequency analogously to the dielectric function in Drude's model of metals. In fact, the proposed torsional elastic surface waves can be considered as an elastic analogue of Surface Plasmon Polariton (SPP) electromagnetic (optical) waves propagating along a metallic rod (cylinder) embedded in a dielectric medium. Consequently, we developed the corresponding analytical equations, for the dispersion relation and group velocity of the new torsional elastic surface wave. The newly discovered torsional elastic surface waves exhibit virtually all extraordinary properties of their electromagnetic SPP counterparts, such as: strong subwavelength concentration of the wave energy in the vicinity of the cylindrical surface ) of the guiding rod, very low phase and group velocities, etc. Therefore, the new torsional elastic surface waves can be used in: a) near-field subwavelength acoustic imaging (superresolution), b) amplification of the evanescent waves c) acoustic wave trapping (zero group and phase velocity). Importantly, the newly discovered torsional elastic surface waves can form a basis for the development of a new generation of ultrasonic sensors (e.g., viscosity sensors), biosensors and chemosensors with a very high mass sensitivity.