Frequency Analysis Of Sounds Research Articles

A study on the difference in noise reduction between rear and side microphone on CPX measurement method through sound absorption frequency analysis

The road noise evaluation method in Korea is based on the 'noise vibration process test standard' by the Ministry of Environment. In this evaluation method, the noise felt at the sound-receiving point is measured as LAeq. Recently, in order to clarify the noise measurement standards for low-noise pavements, an international standard (ISO11819-2, CPX method) was first introduced in the Porous Pavement Guidelines of the Ministry of Land, Infrastructure and Transport. According to ISO, CPX measurement method adopts side microphones as mandatory, and the rear microphone as optional. Due to the difference in location noise level is different, causing confusion in the road noise evaluation method. Researchers have published several studies in the past that the rear microphone is highly correlated with the equivalent noise level method based on the Korean standard. As a follow-up study to the above results, this study examines the characteristics and causes of the frequency spectrum of the rear and side microphones in the case of dense asphalt pavement and porous asphalt pavement and derives the results through frequency analysis of the sound absorption coefficient test to determine and to contribute improving reliability and institutional rationalization of the CPX measurement method.

Spectral and temporal resolution in listeners with age-dependent hearing loss

Two basic mechanisms perform the frequency analysis of sounds: (i) the spectral mechanism presented by a bank of frequency-tuned filters and (ii) The temporal mechanism that uses the temporal structure of the signal. The temporal structure manifests in the autocorrelation function. The roles of the spectral and temporal mechanisms in the age-dependent hearing loss were investigated using rippled-spectrum signals. It has been shown previously that discrimination of two rippled signals with different positions of ripples at the frequency scale is mostly performed the spectral processing; for discrimination between a rippled and “flat” signal, the temporal processing dominated. In cases of hearing loss, the decrease of the acuteness of frequency-tuned cochlear filters resulted in reduction of the ripple-pattern resolution by the spectral mechanism. This effect did not influence the capabilities of the temporal mechanism. However, listeners with the age-dependenthearing loss did not perceive high sound frequencies. High frequencies were more favorable for temporal processing, so the inability to perceive these frequencies negatively influenced the ripple resolution. Thus, resolution of rippled signals may reduce at any discrimination task; however, the mechanisms of the reduction differed depending on the task. [Work supported by The Russian Science Foundation, Grant 23-25-00148.]

Electronic Auscultation System: Processing of Auscultatory Data

The purpose of research is to increase the diversity of electronic auscultation system designs with measured characteristics and testing. The series of articles includes the development of a model of the electronic auscultation system, the design of an electronic stethoscope, the manufacture of an experimental sample, the development of a methodology for measuring the amplitude-frequency characteristics of electronic and classical stethoscopes, testing of the proposed models and methods, analysis of auscultative data. The article considers mathematical methods of primary analysis of auscultative data. Recordings of normal and hard breathing were used for the experiment. Frequency, time-frequency and autocorrelation analysis of respiratory sounds was performed. Methods. The research was based on the theory of digital signal processing. The study uses auscultative data obtained from an experimental sample of an electronic auscultation system. Electronic records of hard (pathological) and normal human breathing over the left middle lung were used. Respiratory noises were converted into digital form with the following parameters: sampling frequency fd = 48 kHz; bit depth n = 24 bits; number of channels 1. To analyze the frequency information content of the recordings, their spectra were constructed. A fast Fourier transform was used to calculate the values in the spectra. Results. In the presented work, the frequency characteristics of recordings of hard and normal breathing are analyzed. The values of autocorrelation functions are obtained. An author-regression model of the process of normal breathing is obtained. The problem of analytical determination of the model order remains open and requires a separate solution. The resulting model allows you to generate an equivalent breathing noise of inhalation or exhalation when a signal with a uniform is applied to its input. Conclusion. A sample of the electronic auscultation system has been tested, methods of simplified primary analysis of auscultative data have been proposed. The difference in the results of the treatment of hard and normal breathing has no statistical significance due to the small sample.

Single-cell transcriptomic profiling of the mouse cochlea: An atlas for targeted therapies

Functional molecular characterization of the cochlea has mainly been driven by the deciphering of the genetic architecture of sensorineural deafness. As a result, the search for curative treatments, which are sorely lacking in the hearing field, has become a potentially achievable objective, particularly via cochlear gene and cell therapies. To this end, a complete inventory of cochlear cell types, with an in-depth characterization of their gene expression profiles right up to their final differentiation, is indispensable. We therefore generated a single-cell transcriptomic atlas of the mouse cochlea based on an analysis of more than 120,000 cells on postnatal day 8 (P8), during the prehearing period, P12, corresponding to hearing onset, and P20, when cochlear maturation is almost complete. By combining whole-cell and nuclear transcript analyses with extensive in situ RNA hybridization assays, we characterized the transcriptomic signatures covering nearly all cochlear cell types and developed cell type-specific markers. Three cell types were discovered; two of them contribute to the modiolus which houses the primary auditory neurons and blood vessels, and the third one consists in cells lining the scala vestibuli. The results also shed light on the molecular basis of the tonotopic gradient of the biophysical characteristics of the basilar membrane that critically underlies cochlear passive sound frequency analysis. Finally, overlooked expression of deafness genes in several cochlear cell types was also unveiled. This atlas paves the way for the deciphering of the gene regulatory networks controlling cochlear cell differentiation and maturation, essential for the development of effective targeted treatments.

Acoustic analysis of jet atomization for uniform dispersion of nano- and micro-droplets

In this study, the mechanisms of jet atomization were analyzed based on a frequency analysis of atomization sounds in the audible range (∼20 kHz). Jet atomization is a two-dimensional, high-speed atomization using a diaphragm, and interesting acoustic signals and atomization phenomena were detected on hydrophobic and hydrophilic diaphragms. The hydrophilic diaphragm strongly interacted and resonated with the surface wave, resulting in symmetrical jet atomization relative to the diaphragm. The resonance between the diaphragm and the surface wave was supported by a calculation of the eigenfrequency of the diaphragm and the coincidence of the droplet diameters as calculated from Lang's equation. Notably, the diaphragm excited by the ultrasonic transducer acted as a new transducer vibrating perpendicular to the transducer. As a result, when the diaphragm and the surface wave were in resonance at 2.4 MHz, a symmetrical two-dimensional high-speed jet atomization was generated in the direction perpendicular to the transducer’s vibration direction. This study also revealed that the atomization state can be determined based on the acoustic analysis. This acoustic analysis of atomization sounds can be applied in more advanced atomization control, such as for providing uniform dispersions of droplets containing DNA, drugs, or microplastics.

The noise absorption prediction of a combined and independent absorber under different conditions and at different frequencies, using the new Engineering Noise Control Software (ENC)

Noise is one of the most harmful factors in the work environment, which is very important to control. There are various techniques to achieve this goal. One of the most important of them is the use of noise absorbers. Absorbent materials are often used to counteract the effects of reflected noise from hard surfaces and reduce their level. This is an experimental-applied study conducted in the physical factor laboratory of the Faculty of Health. The purpose was to predict the Noise absorption rate of combined and independent absorbers under different conditions and frequencies using the new ENC (engineering noise control) software. The sound absorption determination was carried out in 5 stages, including sound frequency analysis for the source, measurement of the dominant frequency, measurement of the absorption coefficient of absorbent materials in different conditions, measurement of the limit frequency (peak frequency of noise absorption) and comparison of the software results with the findings of the impedance tube in Real conditions. The best absorption mode for combined and independent absorbents is using a 5 cm rock wool absorbent with a 2 cm thick air layer behind it without a polyurethane absorbent layer and a 10 cm wide rock wool absorbent with a 1 cm air layer behind it without polyurethane layer. A polyurethane layer on the stone wool absorber decreased the amount of noise absorption for high frequencies. The results obtained from the best absorption conditions in the ENC software were consistent with the findings from the impedance tube device in real situations. The results of this study showed that suitable and optimal conditions of sound absorption could be achieved by using the ENC software, correct design, use of suitable absorbers, changes in the physical parameters of the absorber, and the use of a combined absorber.

A Malfunction Pattern Distinction of an Automotive Electric part by Sound and Vibration Frequency Analysis

A Malfunction Pattern Distinction of an Automotive Electric part by Sound and Vibration Frequency Analysis

A Novel Method of Temporomandibular Joint Hypermobility Diagnosis Based on Signal Analysis.

Despite the temporomandibular joint (TMJ) being a well-known anatomical structure its diagnosis may become difficult because physiological sounds accompanying joint movement can falsely indicate pathological symptoms. One example of such a situation is temporomandibular joint hypermobility (TMJH), which still requires comprehensive study. The commonly used official research diagnostic criteria for temporomandibular disorders (RDC/TMD) does not support the recognition of TMJH. Therefore, in this paper the authors propose a novel diagnostic method of TMJH based on the digital time–frequency analysis of sounds generated by TMJ. Forty-seven volunteers were diagnosed using the RDC/TMD questionnaire and auscultated with the Littmann 3200 electronic stethoscope on both sides of the head simultaneously. Recorded TMJ sounds were transferred to the computer via Bluetooth® for numerical analysis. The representation of the signals in the time–frequency domain was computed with the use of the Python Numpy and Matplotlib libraries and short-time Fourier transform. The research reveals characteristic time–frequency features in acoustic signals which can be used to detect TMJH. It is also proved that TMJH is a rare disorder; however, its prevalence at the level of around 4% is still significant.

Postnatal structural development of mammalian Basilar Membrane provides anatomical basis for the maturation of tonotopic maps and frequency tuning

The basilar membrane (BM) of the mammalian cochlea constitutes a spiraling acellular ribbon that is intimately attached to the organ of Corti. Its graded stiffness, increasing from apex to the base of the cochlea provides the mechanical basis for sound frequency analysis. Despite its central role in auditory signal transduction, virtually nothing is known about the BM’s structural development. Using polarized light microscopy, the present study characterized the architectural transformations of freshly dissected BM at time points during postnatal development and maturation. The results indicate that the BM structural elements increase progressively in size, becoming radially aligned and more tightly packed with maturation and reach the adult structural signature by postnatal day 20 (P20). The findings provide insight into structural details and developmental changes of the mammalian BM, suggesting that BM is a dynamic structure that changes throughout the life of an animal.

Hammering Sound Frequency Analysis to Fix an Acetabular Cup during Total Hip Arthroplasty: Clinical Trials and Biomechanical Studies

Failure during total hip arthroplasty may lead to bedridden of the elderly. Since the acetabulum cup fix in an anatomically deep region, failures, such as loosening and fracture, occur three times more frequently compared with failures of the stem fix in the femur. We investigated the possibility of evaluating whether fixation was acquired by frequency analysis of the hammering sound of implanting a cup into the acetabulum. The subjects were 11 patients (11 joints) who underwent total hip arthroplasty, biomechanical test materials, and orthopedic models. Surgeries and experiments were performed by orthopedists specialized in the hip. A system was constructed with a tablet PC and directional microphone, the peak frequency at which the amplitude reached the maximum was determined, and judgment processing (stable, unstable) of cup fixability was performed in real time. The stable maximum peak frequency observed in the clinical trials was 4.42 ± 4.02 kHz. The mean stable maximum peak frequency in the biomechanical tests was 4.46 ± 1.19 kHz in biomechanical test materials and 4.56 ± 2.02 kHz in orthopaedicmodels. When hammering was continued, the frequency leading to fracture decreased in both biomechanical test materials and orthopaedicmodels. In conclusion, in clinical trials and biomechanical studies, variation of the maximum peak frequency decreased when fixation was acquired and the frequency stabilized. It was suggested that this method can serve as a fixability evaluation method of acetabular cups because analysis can be performed in real time during surgery, for which prevention of intraoperative fracture can be expected.

Numerical investigation of hydrodynamic and hydro-acoustic performance of underwater propeller operating in off-design flow conditions

ABSTRACT This paper is aimed to numerically investigate the hydrodynamic and hydro-acoustic behaviours of rotating underwater propeller operating in off-design flow conditions. The performance of the propeller is subjected to significant alteration, as it experiences flow, coming at an angle. For this purpose, numerical simulation is performed for the INSEAN Propeller E779A. Turbulence model based on the two-equation Reynolds Averaged Navier Stokes (RANS) turbulence model, i.e. k–ω SST (Shear Stress Transport) method is implied to assess hydrodynamic performance, while hydro-acoustic assessment in near field is calculated by coupling RANS with the Ffowcs Williams Hawking (FW-H) equation. Validation is performed by comparing the numerically computed results from the current study with the available experimental data in straight flow conditions and then the off-design conditions are modelled by using the combinations of three advance ratios with four different flow angles. As a result, distinct differences among the hydrodynamic and hydro-acoustic features are analysed. The hydrodynamic coefficients are compared, and their change is analysed in detail. For the hydro-acoustic analysis, sound pressure level, attenuation frequency and directivity analysis are conducted and based on these factors the effect of the off-design condition on the aquatic life is discussed, thus showing the strong influence of the off-design condition on the hydro-acoustics of the underwater water propeller.

Indexing surface smoothness and fiber softness by sound frequency analysis for textile clustering and classification

Cutting-edge technology is being used in the fashion industry for three-dimensional (3D) virtual fitting programs to meet the demand for clothing manufacturing as well as textile simulating. For expanding the textile choices of the program users, this research looks at the indexation of tactile sensations, the texture of fabrics, which has been subjectively evaluated by the human hand. Firstly, this study objectively measured and indexed the surface smoothness and fiber softness of 749 fabrics through a tissue softness analyzer that mimics human hands. Secondly, after statistical analyses of the drape coefficient, each bending distance and Young's modulus for the initial tensile strength in the warp–weft directions, the thickness, and the weight of the fabrics, it was found that drape (Pearson coefficient = 0.532) and bending properties are the key factors in the fabric surface smoothness (TS750), while the fiber softness (TS7) showed a weak correlation with thickness (Pearson coefficient = 0.364), followed by the log value of the Young's modulus in the weft direction. Thirdly, we classified nine clusters for TS750 based on the 11 regression variables with significant Pearson coefficients, and characterized each cluster in order of surface smoothness (TS750) after Duncan post-hoc tests and analyses of variance (all statistically significant, p < 0.01) with microscopic surface images of one sample for each cluster. For precise TS750 classification, we finally trained the 267 samples with the same 11 variables, resulting in 93.3% prediction through an artificial neural network with multiple hidden layers. This prediction with Fisher discriminants for the clusters will enable the 3D virtual program users to predict further clustering of newly added fabrics.

Prediction of Intraoperative Fracture by Hammering Sound Frequency Analysis and Stress Estimation during Total Hip Arthroplasty

When a stem is inserted into the femur during total hip arthroplasty, sufficient fixation depends on the surgeon’s experience. An objective method of evaluating whether the stem has been correctly fixed may aid clinicians in their decision. We examined the relationship between the sound frequency caused by hammering the stem and the internal stress in artificial femurs, and evaluated the utility of sound frequency analysis to prevent intraoperative fracture. Surgeons inserted one of two types of cementless stems (SL-PLUS and modified CLS) using routine operational procedures into 13 artificial femurs. These are the standard Zweymullers used in Europe. The difference is the lateral shape; SL-PLUS has holes for removal and the modified CLS has fins to prevent rotation. We estimated stress in the femur via finite element analysis, measured the hammering force, and recorded the sound of hammering for frequency analysis. Finite element analysis revealed that the hammering sound frequency decreased as the maximum stress increased. A decrease in frequency suggested that fixation was sufficient and that continued hammering would increase the risk of fracture. Thus, evaluation of the change in sound frequency during stem insertion may indicate when the hammering force should be reduced, thereby preventing intraoperative periprosthetic fractures. Further frequency change may also predict fractures prior to visual confirmation. We concluded that sound frequency analysis has potential as an objective evaluation method to help prevent intraoperative periprosthetic fractures during stem insertion.

Frequencies Rotation at High Sound Pressure Levels Toward Low Frequencies

Today, analyzing of sound pressure level and frequency is considered as an important index in human society. Sound experts believe that analyzing of these parameters can help us to better understanding of work environments. Sound measurements and frequency analysis did to fix the harmful frequency in all sections in Shiraz gas power plant with sound analyzer model BSWA 308. The sound pressure levels (LP) and the one and one-third octave band were continuously measured in A and C weighting networks and slow mode for time response. Excel 2013 and Minitab 18.1 software used for statistical calculations. Results analyzed by Minitab 18.1 software. The highest harmful frequency in Shiraz Gas Power Plant (SGPP) was 50 Hz with 115 dB. The sound pressure level (SPL) ranged from 45 dB to 120 dB in one-third octave band and weighting network C. The maximum sound pressure level was in Craft electricity generator with 105.3 dB and 67 Hz. Sound pressure level in surrounded environment was 120 dB. According to the results, in this industry the sound pressure level exceeded the Occupational Exposure Level of Iran (OEL). The value of sound pressure level were higher than the Standard of occupational health. SGPP consumes 47000 cubic meters of natural gas per hour to produce 100 MW (Mega Watt) of electricity. It is very high and it is not economical and cost effective. These numbers indicate that the power plant’s efficiency is low. It could be concluded that the noise pollution is an important issue in these industries. Moreover, SGPP produce noise with loss energy. Frequencies rotation at high sound pressure levels toward low frequencies were happened.

Usefulness of Hammering Sound Frequency Analysis as an Evaluation Method for the Prevention of Trouble during Hip Replacement

In total hip arthroplasty, judgment of the appropriateness of stem hammering is dependent on the experience and feelings of the surgeon and no objective evaluation method has been established. In this study, a frequency analysis of the hammering sounds in total hip arthroplasty was performed to investigate objective judgment criteria capable of preventing problems during surgery. Stem hammering was applied following the surgeon’s feelings as usual in an operating room. A directional microphone was placed at a distance about 2 m from the surgical field and the peak frequency reaching the maximum amplitude was determined by Fourier analysis. It was clarified that the same peak frequency repeats when appropriate fixation is acquired during surgery, suggesting that intraoperative fracture and postoperative loosening can be prevented by stopping hammering at the time the peak frequency converged. Investigation of changes in the hammering sound frequency may serve as objective judgment criteria capable of preventing problems during surgery.

Designing, constructing and testing of a new generation of sound barriers.

Nowadays, noise pollution is considered a major environmental problem which has affected the health and comfort of millions of people around the world. Solving the mentioned problems need to design a new generation of acoustic barriers. Acoustics experts believe that stopping and absorbing the low-frequency sound is difficult. The aims of this study were to remove the harmful frequency in industries and cities. This study concentrates on the reduction of the noise level and increasing the mass law and resonance at low frequencies. Sound measurement and frequency analysis did to fix the harmful frequency in the Shiraz city and in the Shiraz Gas Power Plant. COMSOL 5.3a software used for simulation. Suitable material chose for the manufacture of the sound barrier through the Cambridge engineering selection software 2013. The meta-material sound barrier made and tested in the acoustic room and in the free space. Results analyzed and optimized by Design of Experiment (DOE) and Response Surface Methodology (RSM) software. Mini Tab. 18.1 software used for Statistical Calculations. New sound barriers manufactured with adding new strategies to previous studies to improve the performance of meta-materials like beautification inspired from the flowers of nature and increasing of resonance in internal pipes. Three mechanisms used in this scatterer model which included, resonance phenomenon, Band Gap (BG) without absorption mechanism and inner-fractal-like structure. Our technique showed an advantage to reduce at frequencies below 100Hz without adsorbent usage. The results showed that reduced noise exposures about 17.8dB at frequency 50Hz, about 9.1dB within the range of 250Hz according to EN 1793-2 standard (Lab Test for Airborne Sound Insulation). The sound barrier reported in this work provides the best and updated solution in the field of noise control. A novel generation of sound barriers introduced. We called this structure Interior Quasi-Fractal Sonic Crystal Acoustic Barrier (IQFSCAB). In this study, several different gaps used to remove various frequencies. It could be concluded that the outcomes of the meta-material models based on the Sonic Crystal (SC) could be used for the purpose of noise control system and could be helpful for decision-makers on the noise control legislations. Graphical abstractInteraction of waves with noise barriers and wave propagation inside periodic media is a hot topic in many branches of science and technology. The acoustic metamaterial can create green environments by reducing the low frequencies of industrial noise or traffic jam. New barrier have added a number of new strategies to previous studies in order to improve the performance of meta-materials. Our technique shows a clear advantage over to absorb at frequencies below 100Hz without adsorbent usage. Innovative use of several different gaps and diameters for to remove various frequencies was done in this study. We called this structure IQFSACB due to fractal like interior pipes as those seen in some of the flowers in nature.

Change detection to tone pairs during the first year of life – Predictive longitudinal relationships for EEG-based source and time-frequency measures

Brain responses related to auditory processing show large changes throughout infancy and childhood with some evidence that the two hemispheres might mature at different rates. Differing rates of hemispheric maturation could be linked to the proposed functional specialization of the hemispheres in which the left auditory cortex engages in analysis of precise timing information whereas the right auditory cortex focuses on analysis of sound frequency. Here the auditory change detection process for rapidly presented tone-pairs was examined in a longitudinal sample of infants at the age of 6 and 12 months using EEG. The ERP response related to change detection of a frequency contrast, its estimated source strength in the auditory areas, as well as time-frequency indices showed developmental effects. ERP amplitudes, source strength, spectral power and inter-trial phase locking decreased across age. A differential lateralization pattern emerged between 6 and 12 months as shown by inter-trial phase locking at 2–3 Hz; specifically, a larger developmental change was observed in the right as compared to the left hemisphere. Predictive relationships for the change in source strength from 6 months to 12 months were found. Six-month predictors were source strength and phase locking values at low frequencies. The results show that the infant change detection response in rapidly presented tone pairs is mainly determined by low frequency power and phase-locking with a larger phase-locking response at 6 months predicting greater change at 12 months. The ability of the auditory system to respond systematically across stimuli is suggested as a marker of maturational change that leads to more automatic and fine-tuned cortical responses.

ANIMASI GAMELAN BERBASIS FREKUENSI SUARA

"Gamelan Animation Based Base On Sound Frequency" is a study aimed to find out how to make 3D gamelan animation automatically in accordance with the input of gamelan sound. The gamelan instrument used in this research is the type of saron instrument. The number of blades used in this study 7 pieces, according to the number of saron blades. The final result of this research is 3D animation of saron gamelan. Software used in this research is Blender 3D. This research requires several processes such as in sound frequency analysis, each saron gamelan blade has a slightly different frequency value. In the object hammer required armature or rigging that serves to move the hammer. Each armature is supplied by the driver as a link between the armature and the sound frequency graph. The object of the saron hammer, can move based on the frequency graph. The results showed that with the input frequency of saron the object of animation can move according to the time of the sound of the gamelan saron.

Lung Injury in Asymptomatic Firefighters: Breath Sound Frequency Analysis May Find What Spirometry May Not

Lung Injury in Asymptomatic Firefighters: Breath Sound Frequency Analysis May Find What Spirometry May Not

Heart Sound Frequency Analysis Outperforms ECG in Screening for Hypertrophic Cardiomyopathy

Heart Sound Frequency Analysis Outperforms ECG in Screening for Hypertrophic Cardiomyopathy