Sound Frequency Research Articles

Acoustic-assisted deposition of ordered self-assembled silica opal layers on hydrophilic single crystal diamond substrates

We deposited self-assembled films of a few monolayers of silica spheres from the water-based colloid on vertically moving hydrophilic single crystal diamond substrates. The use of acoustic agitation of the water suspension with the SiO2 nanospheres significantly improved the long-range order of the films with opal structure. The study examines the evolution of the structure, specifically the size of single crystal domains, with the assistance of sound frequency (0–2500 Hz) and intensity (0–125 dB). Optimal (resonance) parameters are determined based on scanning electron microscopy and optical reflection spectroscopy of the films. The production of high-quality photonic crystals, including templates for diamond-based ordered composites and inverse opal structures, is a promising application of acoustic crystallization of opals on diamond substrates.

High-sensitivity trace gas detection based on differential Helmholtz photoacoustic cell with dense spot pattern

A high-sensitivity photoacoustic spectroscopy (PAS) sensor based on differential Helmholtz photoacoustic cell (DHPAC) with dense spot pattern is reported in this paper for the first time. A multi-pass cell based on two concave mirrors was designed to achieve a dense spot pattern, which realized 212 times excitation of incident laser. A finite element analysis was utilized to simulate the sound field distribution and frequency response of the designed DHPAC. An erbium-doped fiber amplifier (EDFA) was employed to amplify the output optical power of the laser to achieve strong excitation. In order to assess the designed sensor's performance, an acetylene (C2H2) detection system was established using a near infrared diode laser with a central wavelength 1530.3 nm. According to experimental results, the differential characteristics of DHPAC was verified. Compared to the sensor without dense spot pattern, the photoacoustic signal with dense spot pattern had a 44.73 times improvement. The minimum detection limit (MDL) of the designed C2H2-PAS sensor can be improved to 5 ppb when the average time of the sensor system is 200 s.

Correlation Between Implant Stability Quotient and Percussion Sound Frequency.

To determine the correlation between the primary implant stability quotient and the implant percussion sound frequency. A total of 14 pigs' ribs were scanned using a dental cone beam computed tomography (CBCT) scanner to classify the bone specimens into three distinct bone density Hounsfield units (HU) value categories: D1 bone: >1250 HU; D2: 850-1250 HU; D3: <850 HU. Then, 96 implants were inserted: 32 implants in D1 bone, 32 implants in D2 bone, and 32 implants in D3 bone. The primary implant stability quotient (ISQ) was analyzed, and percussion sound was recorded usinga wireless microphone connected and analyzed with frequency analysis software. Statistically significant positive correlations were found between the primary ISQ and the bone density HU value (r = 0.719; p < 0.001), and statistically significant positive correlations between the primary ISQ and the percussion sound frequency (r = 0.606; p < 0.001). Furthermore, significant differences inprimary ISQ values and percussion sound frequency were found between D1 and D2 bone, as well as between D1 and D3 bone. However, no significant differences were found in primary ISQ values and percussion sound frequency between D2 and D3 bone. The primary ISQ value and the percussion sound frequency are positively correlated.

Distal but not local auditory information supports spatial representations by place cells.

Sound is an important navigational cue for mammals. During spatial navigation, hippocampal place cells encode spatial representations of the environment based on visual information, but to what extent audiospatial information can enable reliable place cell mapping is largely unknown. We assessed this by recording from CA1 place cells in the dark, under circumstances where reliable visual, tactile, or olfactory information was unavailable. Male rats were exposed to auditory cues of different frequencies that were delivered from local or distal spatial locations. We observed that distal, but not local cue presentation, enables and supports stable place fields, regardless of the sound frequency used. Our data suggest that a context dependency exists regarding the relevance of auditory information for place field mapping: whereas locally available auditory cues do not serve as a salient spatial basis for the anchoring of place fields, auditory cue localization supports spatial representations by place cells when available in the form of distal information. Furthermore, our results demonstrate that CA1 neurons can effectively use auditory stimuli to generate place fields, and that hippocampal pyramidal neurons are not solely dependent on visual cues for the generation of place field representations based on allocentric reference frames.

Collimated beam formation in 3D acoustic sonic crystals

We demonstrate strongly collimated beam formation, at audible frequencies, in a three-dimensional acoustic phononic crystal where the wavelength is commensurate with the crystal elements; the crystal is a seemingly simple rectangular cuboid constructed from closely-spaced spheres, and yet demonstrates rich wave phenomena acting as a canonical three-dimensional metamaterial. We employ theory, numerical simulation and experiments to design and interpret this collimated beam phenomenon and use a crystal consisting of a finite rectangular cuboid array of 4×10×10 polymer spheres 1.38 cm in diameter in air, arranged in a primitive cubic cell with the centre-to-centre spacing of the spheres, i.e. the pitch, as 1.5 cm. Collimation effects are observed in the time domain for chirps with central frequencies at 14.2 kHz and 18 kHz, and we deployed a laser feedback interferometer or Self-Mixing Interferometer – a recently proposed technique to observe complex acoustic fields—that enables experimental visualisation of the pressure field both within the crystal and outside of the crystal. Numerical exploration using a higher-order multi-scale finite element method designed for the rapid and detailed simulation of 3D wave physics further confirms these collimation effects and cross-validates with the experiments. Interpretation follows using High Frequency Homogenization and Bloch analysis whereby the different origin of the collimation at these two frequencies is revealed by markedly different isofrequency surfaces of the sonic crystal.

Improved tactile speech perception and noise robustness using audio-to-tactile sensory substitution with amplitude envelope expansion

Recent advances in haptic technology could allow haptic hearing aids, which convert audio to tactile stimulation, to become viable for supporting people with hearing loss. A tactile vocoder strategy for audio-to-tactile conversion, which exploits these advances, has recently shown significant promise. In this strategy, the amplitude envelope is extracted from several audio frequency bands and used to modulate the amplitude of a set of vibro-tactile tones. The vocoder strategy allows good consonant discrimination, but vowel discrimination is poor and the strategy is susceptible to background noise. In the current study, we assessed whether multi-band amplitude envelope expansion can effectively enhance critical vowel features, such as formants, and improve speech extraction from noise. In 32 participants with normal touch perception, tactile-only phoneme discrimination with and without envelope expansion was assessed both in quiet and in background noise. Envelope expansion improved performance in quiet by 10.3% for vowels and by 5.9% for consonants. In noise, envelope expansion improved overall phoneme discrimination by 9.6%, with no difference in benefit between consonants and vowels. The tactile vocoder with envelope expansion can be deployed in real-time on a compact device and could substantially improve clinical outcomes for a new generation of haptic hearing aids.

Study on the Effects of Sound and Music as Medicine on Cardiovascular Health

This paper explores the dual impact of Sound frequencies and music on cardiovascular health, analyzing how sound frequencies and musical interventions influence cardiovascular risk factors and outcomes. While environmental factors have been linked to an increase in cardiovascular diseases due to stressrelated mechanisms, Sound frequencies and music therapy offer potential benefits through their calming effects on the autonomic nervous system.

Design of an electronic device in the STEAM context to relate results of physical measurements with sounds, and its analysis through science teachers' perception

This work presents the design and details of an electronic system that uses software and hardware aspects to generate sound frequencies associated with the measurement of physical phenomena, such as temperature or other. It has potential to create fun and motivation activities in the classroom, encouraging the students to think about the association between scientific and technological aspects. It is based on a STEAM (Science, Technology, Engineering, Arts, and Mathematics) approach where an Arduino processing board measures a physical phenomenon value with a sensor, computes a mathematical relationship to define an associated sound frequency, and next sends an output signal to excite a speaker. The proposed electronic system is simple, but this subject may not be very familiar to many science teachers and, therefore, this article explains it step by step to allow its effective understanding and later usage in the classroom. Furthermore, this article also presents a discussion with science teachers in order to analyze their perception when they are challenged to understand and analyze the proposed system under a teaching perspective, which emphasized concernments such as the lack of training and materials, but positively indicates the proposal is feasible and has a satisfactory teaching potential.

The Status of Occupational Noise in Some Selected Factories on Libya

In this paper occupational noise levels atselected factories were measured and compared with the international permissible levels using the integratingsound level meter (Quest 2800) during the year 2007.The calibration of the instrument was carried out beforeand after each measurement using the acousticcalibrator (Quest CA-12B calibrator). The methodwhich was followed was measuring the sound pressurelevel of the different noise sources over a broadfrequency band covering the audible frequency rangeusing the (Octave band filter, model OB-100),disregarding variation with time.From the obtained results, some noise levels whichwere recorded were within the permissible levels i.e.below 90 dBA and some noise levels were higher thanthe permissible limit as at Janzoor textile factory(95dBA), Benghazi Macaroni factory (100dBA), andnear the air blowers at Zletin cement factory, Benghazicement factory (97-100 dBA) in these cases suggestionswere made to minimize the problem.

Laminated acoustic metamaterials for low-frequency broadband ultra-strong sound insulation

In this paper, a kind of laminated acoustic metamaterials (LAMS), which can realize the bandwidth widening and amplitude improvement through the parallel coupling of in-plane gradient parameters and the series laminated design in the thickness direction of the local resonance units, is proposed. The designed LAMS consists of two different layers of single-layer acoustic metamaterials (SLAMs) laminated in series in the thickness direction. During the design process of the two layers of SLAMs, non-uniform mass distribution and non-consistent frame coupling layouts are respectively introduced to broaden the sound insulation frequency band of the acoustic metamaterials. Through careful design, the two layers of SLAMs have distinct working frequency bands, effectively preventing the occurrence of sound insulation valleys with low amplitude. Based on numerical analysis of two layers of SLAMs, this study discusses the results of transmission loss (TL) and the working mechanism of interlayer superposition coupling sound insulation. The analysis of TL for LAMS reveals its capability to achieve ultra-strong sound insulation effects across a low-frequency broadband range. The accuracy of the numerical analysis in this study is verified through semi-analytical methods and small-scale impedance tube experiments. The LAMS proposed in this paper holds significant potential for wide-band noise reduction control in various high-noise mechanical equipment or workplaces.

Effect of ultrasonic on thermo-hydraulic characteristics of shell and tube heat exchangers with twisted tape

Ultrasonic technology was combined with twisted tape insert technology to improve the performance of shell and tube heat exchangers. The effects of sound intensity, sound frequency, and ultrasonic transducer position on thermal transfer, resistance reduction, and overall performance of shell and tube heat exchangers with twisted tape (STHXTT) at different Reynolds numbers were investigated compared to the non-ultrasonic conditions. The experimental results show that applying ultrasonic can significantly enhance thermal transfer, reduce flow resistance, and improve the overall performance. The maximum increase of Nu is 36.53 %, the maximum decrease of f is 12.50 %, and the maximum value of PEC is 1.41. With the increase in Reynolds number, the performance is enhanced but the resistance reduction and overall performance are weak. When the ultrasonic intensity increases, the thermal transfer and resistance reduction performance is enhanced, but a critical ultrasonic intensity exists. When the ultrasonic intensity is large enough, the ability to reduce resistance is enhanced with the decrease of ultrasonic frequency. When the ultrasonic transducer is installed vertically, the thermal transfer performance is the best, however, the resistance reduction effect is the worst. When installed horizontally, the STHXTT has the best resistance reduction performance but the worst thermal transfer effect.

Experimental and numerical evaluation of the influence of voids on sound absorption behaviors of 3D printed continuous flax fiber reinforced PLA composites

This study aims to quantitatively analyze the effects of voids on sound absorption properties of 3D printed continuous flax fiber reinforced PLA composites (CFFRCs). Three kinds of flax yarns with different linear density were employed to prepare CFFRCs via 3D printing technology. The sound absorption performances of these composites were measured using the impedance tube based on the two-microphone transfer function method. The microstructure morphologies including cross-sections of flax yarns, voids shape and distributions of the composites were observed via ultra-depth microscope and micro-computed tomography to reconstruct the exact structures in simulation. Mercury intrusion porosimetry was applied to measure the voids dimensions of CFFRCs. The influence of voids on sound absorption mechanisms of CFFRCs were revealed based on thermoviscous acoustics theory by conducting the simulation in COMSOL software. The experimental results demonstrated that CFFRCs exhibited excellent sound absorption coefficients (close to 1) within the frequency range of 150–350 Hz and 350–550 Hz, resulting from the voids inside and between the flax yarns respectively. With the increase of linear density (diameter of the yarn), the contents of voids inside and between the flax yarns both increased. The dimensions of voids inside the flax yarns improved while those between flax yarns remained unchanged. The existence of the voids between the flax yarns resulted in a decrease in the sound absorption coefficient of CFFRCs, while more voids inside flax yarns led to the increase of the sound absorption frequency. Numerical results indicated that voids between the flax yarns contributed to a more uniform change in sound speed, reducing sound absorption performance. Whereas, voids inside the flax yarns could improve viscous friction of soundwaves due to narrow structures, enhancing sound absorption capabilities. This study is anticipated to provide a guidance for the design of integration of structure and function of 3D printed CFFRCs.

A zebrafish-based acoustic motor response (AMR) assay to evaluate chemical-induced developmental neurotoxicity

Behavioral assays using early-developing zebrafish (Danio rerio) offer a valuable supplement to the in vitro battery adopted as new approach methodologies (NAMs) for assessing risk of chemical-induced developmental neurotoxicity. However, the behavioral assays primarily adopted rely on visual stimulation to elicit behavioral responses, known as visual motor response (VMR) assays. Ocular deficits resulting from chemical exposures can, therefore, confound the behavioral responses, independent of effects on the nervous system. This highlights the need for complementary assays employing alternative forms of sensory stimulation. In this study, we investigated the efficacy of acoustic stimuli as triggers of behavioral responses in larval zebrafish, determined the most appropriate data acquisition mode, and evaluated the suitability of an acoustic motor response (AMR) assay as means to assess alterations in brain activity and risk of chemical-induced developmental neurotoxicity. We quantified the motor responses of 120 h post-fertilization (hpf) larvae to acoustic stimuli with varying patterns and frequencies, and determined the optimal time intervals for data acquisition. Following this, we examined changes in acoustic and visual motor responses resulting from exposures to pharmacological agents known to impact brain activity (pentylenetetrazole (PTZ) and tricaine-s (MS-222)). Additionally, we examined the AMR and VMR of larvae following exposure to two environmental contaminants associated with developmental neurotoxicity: arsenic (As) and cadmium (Cd). Our findings indicate that exposure to a 100 Hz sound frequency in 100 ms pulses elicits the strongest behavioral response among the acoustic stimuli tested and data acquisition in 2 s time intervals is suitable for response assessment. Exposure to PTZ exaggerated and depressed both AMR and VMR in a concentration-dependent manner, while exposure to MS-222 only depressed them. Similarly, exposure to As and Cd induced respective hyper- and hypo-activation of both motor responses. This study highlights the efficiency of the proposed zebrafish-based AMR assay in demonstrating risk of chemical-induced developmental neurotoxicity and its suitability as a complement to the widely adopted VMR assay.

Visual‐Audio Thermoelectric Detectors for Images and Sound Recognition

AbstractInherent in humans is the capacity to perceive music and art, engaging both the visual and auditory senses, with profound effects on physiological and psychological states. Sound and light possess the remarkable ability to transform into thermal energy and, ultimately, electrical signals, playing a crucial role in human sensory perception. This research introduces a previously unmentioned synesthesia‐inspired image and sound recognition system, diverging from conventional image/sound acquisition techniques based on photo/mechanical‐electrical conversion. Leveraging the photo/acoustic‐thermal‐electric effects, the system utilizes micro‐/commercial thermoelectric devices as a conduit for energy conversion. It successfully discriminates monochromatic red, green, blue (RGB) and color coverage, showcasing its proficiency in distinguishing ten digital paintings. Additionally, by probing fiber responses to varied sound frequencies and loudness levels, the system achieves time‐domain identification of four classical music compositions. The device exhibits high sensitivity to detecting input energy and its inputting rate power, offering a novel approach to image and sound recognition through thermal signals. Potential applications span from bionic image sensors and time‐domain thermal monitoring of audio. With further exploration, this thermoelectric‐based system holds promise in quantifying emotional responses to images and sound.

94‐2: Improved Simulation Accuracy for a Front‐Firing Panel Speaker (FFPS) with Thin‐Actuator by Adopting Frequency‐Dependent Viscoelastic Properties

In this study, we examine methods to enhance the simulation accuracy of Front‐Firing Panel Speakers (FFPS) based on thin actuators. Specifically, we investigate the frequency‐dependent behavior of adhesives’ viscoelastic properties. By leveraging the time‐temperature superposition (TTS) principle, we can accurately determine the material properties at audio frequencies and integrate them into the simulation process. We anticipate that our finding will enhance the efficiency of the design process for FFPS and its display components by simulating more accurate results.

Experimental research on dynamic response characteristics of lean premixed flame excited by acoustic standing wave

The compact combustor holds great potential in the aerospace field. However, it faces challenges in terms of interaction between acoustic waves and flames, which affects combustion efficiency and intensity. In this study, the dynamic response of lean premixed flames under the excitation of a transverse standing wave acoustic field with different frequencies and amplitudes. The results indicate that the flame's response frequency is consistent with the excitation frequency. Decreasing the sound wave frequency and increasing the sound amplitude both lead to an increase in flame area oscillation, thereby enhancing the heat release rate. However, excessively high sound pressure values can enhance fuel diffusion, resulting in a reduction in flame area or even local flame extinction, which significantly decreases flame intensity. This research provides valuable insights into the behavior of lean premixed flames under acoustic excitation, contributing to the optimization of combustion processes and improvement of efficiency and performance in compact combustors.

Design and Research of a Certain Type of Automatic Alarm Equipment

Rapid detection of oxygen leaks in pipelines is crucial to prevent catastrophic accidents. This paper presents the design of an oxygen leakage detection and alarm instrument that converts ultrasonic signals, generated by gas escaping through small holes, into audible frequencies for headset use. This instrument is particularly suitable for ensuring the airtightness of oxygen supply systems for flight crews, engine startup supplemental oxygen systems, and four-station oxygen supply equipment. The design integrates ultrasonic principles, signal processing, computer control, and anti-jamming technologies to detect even minor leaks from a distance. The modular design includes components such as ultrasonic sensors, preamplifiers, filtering circuits, and microcontrollers, ensuring high detection sensitivity and reliability. The alarm system features light and sound alerts, enhancing maintenance efficiency and safety. This modern precision testing instrument significantly improves upon traditional leak detection methods like soapy water tests.

Повышение акустической безопасности производственного помещения

Sound-emitting production and technological as well as engineering equipment located within the enclosed space of industrial premises can form paired interacting sound fields with similar values of expressed dominant emission frequencies in the spectra, ultimately causing the formation of a physical process of sound vibration beats. The process manifests in negative psychoacoustic impacts on a human characterized by pulsating sound pressure levels over time with a pulsation frequency equal to the difference between similar frequency values of discrete components of interacting sound fields. The article provides the results of experimental studies to determine the required value of frequency mismatch of sound fields for individual sources of noise emissions mounted in industrial premises. The industrial premises have been presented as a rectangular parallelepiped with rigid sound-reflective fences. Simulation experiments have been carried out using an electroacoustic sound-emitting system represented as two autonomous sound-emitters — electroacoustic loudspeakers. The loudspeakers have simulated noise-generating engineering units with the specified passport steady-state speed operating modes ns and accompanied by the respective established physical processes of sound energy emission whose spectral composition contains specific discrete values of operating dominant functional sound frequencies fs. The technical result of the study is achieved by the implementation of a sufficient degree of frequency mismatch of expressed discrete components of sound emissions of individual autonomous sources of noise preventing the formation of the physical process of generation of intense sound vibration beats. The suggested technical method aiming to increase the acoustic safety of industrial premises assumes that the discrete values of operating dominant functional sound frequencies fs differ from each other by a limiting value Δf exceeding the value of 5 Hz.

Exploring ultrasonic communication in mice treated with Cannabis sativa oil: Audio data processing and correlation study with different behaviours.

Studying ultrasonic vocalizations (USVs) plays a crucial role in understanding animal communication, particularly in the field of ethology and neuropharmacology. Communication is associated with social behaviour; so, USVs study is a valid assay in behavioural readout and monitoring in this context. This paper delved into an investigation of ultrasonic communication in mice treated with Cannabis sativa oil (CS mice), which has been demonstrated having a prosocial effect on behaviour of mice, versus control mice (vehicle-treated, VH mice). To conduct this study, we created a dataset by recording audio-video files and annotating the duration of time that test mice spent engaging in social activities, along with categorizing the types of emitted USVs. The analysis encompassed the frequency of individual sounds as well as more complex sequences of consecutive syllables (patterns). The primary goal was to examine the extent and nature of diversity in ultrasonic communication patterns emitted by these two groups of mice. As a result, we observed statistically significant differences for each considered pattern length between the two groups of mice. Additionally, the study extended its research by considering specific behaviours, aiming to ascertain whether dissimilarities in ultrasonic communication between CS and VH mice are more pronounced or subtle within distinct behavioural contexts. Our findings suggest that while there is variation in USV communication between the two groups of mice, the degree of this diversity may vary depending on the specific behaviour being observed.

An integral wavy shaped P(VDF-TrFE) transducer for audio directional system

To generate self-demodulated low-frequency acoustic waves with high directivity in audio directional system, an integral piezoelectric P(VDF-TrFE) 80/20 mol% film, proving as a typical ferroelectricity and exhibiting the excellent electromechanical coupling factors, is formed into a regular wavy shaped transducer. The frequency response and directivity performances of the large-size transducer are theoretically simulated using COMSOL software, showing that the response is relative smooth over the audio frequency range. As such, the highest sound pressure level is located at a resonant frequency of 40 kHz, while the sound is highly directional and the 3-dB beam-width becomes increasingly sharp with the raise of size of P(VDF-TrFE) film. Interestingly, the integral wavy shaped P(VDF-TrFE) transducer exhibits a sound pressure of 78 dB at 500 mm and the 3-dB beam-widths of 100 Hz,1 kHz, and 6 kHz are ±2.8º, ±3.1º, and ±2.9º, respectively. Thus, the wavy type P(VDF-TrFE) transducer is duplicatable and easy to facilitate extra-large for emerging applications.