Goal: Intracochlear sound pressure (ICSP) measurements are limited by the small dimensions of the human inner ear and the requirements imposed by the liquid medium. A robust intracochlear acoustic ...receiver (ICAR) for repeated use with a simple data acquisition system that provides the required high sensitivity and small dimensions does not yet exist. The work described in this report aims to fill this gap and presents a new microelectromechanical systems (MEMS) condenser microphone (CMIC)-based ICAR concept suitable for ICSP measurements in human temporal bones. Methods: The ICAR head consisted of a passive protective diaphragm (PD) sealing the MEMS CMIC against the liquid medium, enabling insertion into the inner ear. The components of the MEMS CMIC-based ICAR were expressed by a lumped element model (LEM) and compared to the performance of successfully fabricated ICARs. Results: Good agreement was achieved between the LEM and the measurements with different sizes of the PD. The ICSP measurements in a human cadaver temporal bone yielded data in agreement with the literature. Conclusion: Our results confirm that the presented MEMS CMIC-based ICAR is a promising technology for measuring ICSP in human temporal bones in the audible frequency range. Significance: A sensor for evaluation of the biomechanical hearing process by quantification of ICSP is presented. The concept has potential as an acoustic receiver in totally implantable cochlear implants.
In structural receptances, the zeros (antiresonances) define those frequencies at which vibrations disappear. In this paper, the zero sound pressure frequency is defined as the frequency at which the ...sound pressure is zero at certain locations. A method for the assignment of zero sound pressure frequencies using measured sound pressure receptances and structural receptances is proposed through two forms of structural modifications: rank-one modification and higher-rank modification. In rank-one modification, the sound pressure receptances of the modified structure are obtained by using the structural receptances with the Sherman-Morrison formula. In higher-rank modification, the modifications are determined by an analysis of the null space of a matrix consisting of structural receptances and sound pressure receptances. This method requires only a few structural receptances and sound pressure receptances, and no structural models or acoustic models are needed. Numerical examples involving a baffled plate vibrating in air and a fluid-loaded finite cylindrical shell are used to demonstrate the methods. Numerical results show that the zero sound pressure frequencies can be assigned to specific frequencies by structural modification.
Abstract
The article presents various types of emitter designs and schemes of emitting surfaces for the formation of ultrasonic fields with different characteristics and directivity. 4 types of ...emitters have been developed and their main characteristics have been determined. It has been established that a radiator with a flat frontal surface provides 167 dB and makes it possible to intensify a number of technological processes in the near zone (up to 1 meter), such as coagulation and drying. An emitter with a step-variable surface and predominant radiation of one phase of oscillations makes it possible to create a homogeneous ultrasonic field in the air at a sound pressure level of 155-157 dB at a distance of up to 2 meters to the emitter. Focusing radiators allow to provide sound pressure level up to 173 - 177 dB in the focus (at a distance of 0.3 m), while in the far zone the intensity drops significantly (up to 145-150 dB).
Heart failure (HF) is one of the most life-threatening diseases globally. HF is an under-diagnosed condition, and more screening tools are needed to detect it. A few recent studies have suggested ...that HF also affects the functioning of the speech production mechanism by causing generation of edema in the vocal folds and by impairing the lung function. It has not yet been studied whether these possible effects of HF on the speech production mechanism are large enough to cause acoustically measurable differences to distinguish speech produced in HF from that produced by healthy speakers. Therefore, the goal of the present study was to compare speech production between HF patients and healthy controls by focusing on the excitation signal generated at the level of the vocal folds, the glottal flow. The glottal flow was computed from speech using the quasi-closed phase glottal inverse filtering method and the estimated flow was parameterized with 12 glottal parameters. The sound pressure level (SPL) was measured from speech as an additional parameter. The statistical analyses conducted on the parameters indicated that most of the glottal parameters and SPL were significantly different between the HF patients and healthy controls. The results showed that the HF patients generally produced a more rounded glottal pulse and a lower SPL level compared to the healthy controls, indicating incomplete glottal closure and inappropriate leakage of air through the glottis. The results observed in this preliminary study indicate that glottal features are capable of distinguishing speakers with HF from healthy controls. Therefore, the study suggests that glottal features constitute a potential feature extraction approach which should be taken into account in future large-scale investigations in studying the automatic detection of HF from speech.
•A new database for healthy and heart failure (HF) voices is described.•Glottal flow characteristics in patients with HF is analyzed using vowel sounds.•Through statistical analyses we show that the glottal parameters vary significantly between healthy and HF voice.•The glottal source analysis is an effective diagnostic tool for detection of HF.
Abstract
At present, in the detection and identification of underwater noise sources, one of the most commonly used transducer arrays is the circumferential transducer array. The circumferential ...transducer array is symmetrical in space and has high withstand voltage capability and small sound pressure fluctuation in the horizontal beam. Its directivity is an important index that affects the performance of the array. This paper focuses on the directivity maps of circular arrays with different sizes and numbers of elements. From the graph, it is concluded that the undulation of the directivity graph of the circular array is directly related to the array element spacing. The smaller the array element spacing is, the smaller the undulation is, and vice versa. The directivity formula and law can provide technical guidance for the design of a uniform circular transducer array.
Currently, tail flues of coal-fired power plants are treated using wet desulfurization process to remove pollutants. But, the treated flue gas has a significant moisture loss and this process also ...contributes to environmental pollution. Acoustic agglomeration is a non-contact treatment process that can effectively solve the problem of moisture loss in flue gas; however, there are few theoretical and experimental studies on acoustic droplet agglomeration applied to coal-fired power generation. In this paper, an experimental platform for acoustic droplet agglomeration is demonstrated to recover moisture. Further, the effects of important factors such as acoustic frequency, sound pressure level and droplet flow rate on the agglomeration efficiency are investigated. The experimental results show that there are two optimal frequencies exist, namely 500 Hz and 1200 Hz, for the droplets used in this experiment with acoustic droplet agglomeration. A highest efficiency of 58% is achieved at 500 Hz. The acoustic action differs between the 500 Hz and 1200 Hz cases. The analysis suggests that the primary force driving droplet agglomeration at 500 Hz is likely the acoustic flow effect. On the other hand, the main mechanism behind acoustic agglomeration at 1200 Hz could be related to the acoustic wake effect. Sound pressure level is the primary factor affecting droplet agglomeration, and the agglomeration efficiency increases with sound pressure, reaching 96.7% at 150 dB. Furthermore, the agglomeration effect shows a positive correlation with droplet flow rate, while the agglomerated particle size also increases simultaneously. This research provides a new idea for moisture recovery, which could offer valuable insights for implementing acoustic droplet agglomeration and moisture recovery in power plants.
The infrasound levels due to the blade-tower interaction generated by a wind turbine in the publication by Pilger and Ceranna (JSV, Vol. 388, pp. 188–200, 2017) have to be corrected to be interpreted ...as sound pressure level. Also, the electrical power of the wind turbine should be corrected for the high wind case to 660 kW. We provide a reanalysis of the measured data with a power spectrum showing levels for the low-frequency signal of the wind turbine about 34 dB below the original work. All measured levels at a distance of 200 m from the wind turbine's infrasound signal are well below the hearing threshold.
: Hearing loss is defined as worsening of hearing acuity and is usually expressed as an increase in the hearing threshold. Tinnitus, defined as "ringing in the ear", is a common and often disturbing ...accompaniment of hearing loss. Hearing loss and environmental exposures to noise are increasingly recognized health problems.
: The objective was to assess whether the exposure-response relationship can be established between exposures to non-occupational noise and permanent hearing outcomes such as permanent hearing loss and tinnitus.
: Computer searches of all accessible medical and other databases (PubMed, Web of Science, Scopus) were performed and complemented with manual searches. The search was not limited to a particular time span, except for the effects of personal listening devices (PLDs). The latter was limited to the years 2008-June 2015, since previous knowledge was summarized by SCENIHR descriptive systematic review published in 2008.
The inclusion criteria were as follows: the exposure to noise was measured in sound pressure levels (SPLs) and expressed in individual equivalent decibel values (L
), the studies included both exposed and reference groups, the outcome was a permanent health effect, i.e., permanent hearing loss assessed with pure-tone audiometry and/or permanent tinnitus assessed with a questionnaire. The eligibility criteria were evaluated by two independent reviewers.
The risk of bias was assessed for all of the papers using a template for assessment of quality and the risk of bias. The GRADE (grading of recommendations assessment, development, and evaluation) approach was used to assess the overall quality of evidence. Meta-analysis was not possible due to methodological heterogeneity of included studies and the inadequacy of data.
Out of 220 references identified, five studies fulfilled the inclusion criteria. All of them were related to the use of PLDs and comprised in total of 1551 teenagers and young adults. Three studies used hearing loss as the outcome and three tinnitus. There was a positive correlation between noise level and hearing loss either at standard or extended high frequencies in all three of the studies on hearing loss. In one study, there was also a positive correlation between the duration of PLD use and hearing loss. There was no association between prolonged listening to loud music through PLDs and tinnitus or the results were contradictory. All of the evidence was of low quality.
The studies are cross-sectional. No study provides odds ratios of hearing loss by the level of exposure to noise.
While using very strict inclusion criteria, there is low quality GRADE evidence that prolonged listening to loud music through PLDs increases the risk of hearing loss and results in worsening standard frequency audiometric thresholds. However, specific threshold analyses focused on stratifying risk according to clearly defined levels of exposure are missing. Future studies are needed to provide actionable guidance for PLDs users. No studies fulfilling the inclusion criteria related to other isolated or combined exposures to environmental noise were identified.
PDF
