Spatially-varying impedance model for locally reacting acoustic liners at a high sound intensity

2022 ◽  
pp. 116741
Author(s):  
Rémi Roncen ◽  
Fabien Méry ◽  
Estelle Piot ◽  
Patricia Klotz
Keyword(s):  
Sound Intensity ◽  
Impedance Model ◽  
Acoustic Liners ◽  
Spatially Varying ◽  
High Sound

scholarly journals Modulatory Effects of Regional Cortical Activation on the Onset Responses of the Cat Medial Geniculate Neurons

1997 ◽  
Vol 77 (2) ◽  
pp. 896-908 ◽  
Author(s):  
Jufang He
Keyword(s):  
Sound Intensity ◽  
Noise Burst ◽  
Inhibitory Effect ◽  
Cortical Activation ◽  
Facilitatory Effect ◽  
Stimulation Site ◽  
Inhibitory Effects ◽  
Medial Geniculate ◽  
High Sound ◽  
Onset Responses

He, Jufang. Modulatory effects of regional cortical activation on the onset responses of the cat medial geniculate neurons. J. Neurophysiol. 77: 896–908, 1997. Corticofugal modulation on activity of the medial geniculate body (MGB) was examined by locally activating the primary auditory cortex (AI) and looking for effects on the onset responses of MGB neurons to acoustic stimuli. Of 103 MGB neurons recorded from 13 hemispheres of 11 animals, 91 neurons (88%) showed either a facilitatory or inhibitory effect or both; of these neurons, 72 showed facilitatory effects and 25 inhibitory effects. The average facilitatory effect was large, with a mean increase of 62.4%. Small inhibitory effects (mean: −16.2%) were obtained from a few neurons (6 of 103) when a pure tone stimulus was used, whereas the effect became larger and more frequent when a noise burst stimulus was used (mean: −27.3%, n = 22 of 27 neurons). Activation of an AI site having the same best frequency (BF) as the MGB neuron being recorded from produced mainly a facilitatory effect on MGB neuronal responses to pure tones. Activation of AI at a site neighboring the BF site produced inhibitory effects on the MGB response when noise burst stimuli were used. We found that the effective stimulation sites in AI that could modulate MGB activity formed patchlike maps with a diameter of 1.13 ± 0.09 (SE) mm (range 0.6–1.9 mm, n = 15) being larger than the patches of thalamocortical terminal fields. Examining the effects of sound intensities, of 18 neurons tested 9 neurons showed a larger effect for low-sound-intensity stimuli and small or no effects for high-sound-intensity stimuli. These were named low-sound-intensity effective neurons. Five neurons showed high sound intensity effectiveness and four were non-intensity specific. Most low-sound-intensity effective neurons were monotonic rate-intensity function neurons. The AI cortical modulatory effect was frequency specific, because 15 of 27 neurons showed a larger facilitatory effect when a BF stimulus was used rather than a stimulus of any other frequency. The corticothalamic connection between the recording site in MGB and the most effective stimulation site in AI was confirmed by injecting wheat germ agglutinin–horseradish peroxidase tracer at the stimulation site and producing a small lesion in the recording site. The results suggest that 1) the large facilitation effects obtained by AI activation at the region that directly projected to the MGB could be the result mainly of the direct projection terminals to the MGB relay neurons; 2) the large size patches of the effective stimulation site in AI could be due to widely ramifying corticothalamic projections; and 3) the corticofugal projection selectively gates auditory information mainly by a facilitatory effect, although there is also an inhibitory effect that depends on the sound stimulus used.

Realizing broadband sub-wavelength focusing and a high intensity enhancement with a space-time synergetic modulated acoustic prison

2020 ◽  
Vol 8 (28) ◽  
pp. 9511-9519
Author(s):  
Fuyin Ma ◽  
Jianyu Chen ◽  
Jiu Hui Wu ◽  
Han Jia
Keyword(s):  
High Intensity ◽  
Sound Intensity ◽  
Space Time ◽  
Intensity Enhancement ◽  
High Sound ◽  
Sub Wavelength

We experimentally demonstrate broadband sub-wavelength focusing and a high sound intensity enhancement using an acoustic prison.

Latency of unit responses in cochlear nucleus determined in two different ways

1975 ◽  
Vol 38 (4) ◽  
pp. 812-821 ◽  
Author(s):  
A. R. Moller
Keyword(s):  
Cochlear Nucleus ◽  
Time Integration ◽  
Sound Intensity ◽  
Propagation Delay ◽  
Step Response ◽  
Spike Density ◽  
Cross Covariance ◽  
Statistical Signal Analysis ◽  
Small Increments ◽  
High Sound

The latency revealed by poststimulus time histograms of the responses of single units in the cochlear nucleus to tone bursts was compared with the latency of the change in discharge frequency in response to small increments in the amplitude of the stimulus. The latter was derived on the basis of statistical signal analysis of the discharge pattern in response to tones amplitude modulated with pseudorandom noise. The "step response" of the system was computed by time integration of the cross covariance between modulation and spike density. The following observations can be made: 1. The latency of the responses to tone bursts always decreased with increasing sound intensity, whereas the latency of the step response was almost constant for intensities from immediately above threshold to the highest intensity used (60-70 dB above threshold). 2. In most units the latency revealed by the PST histogram of the responses to tone bursts approached the value of latency of the step response asymptotically. 3. In some units with longer latency, the latency of the response to tone bursts was many times greater than the latency of the step response, even at high sound intensities. 4. A histogram of latency values of the step response of the units studied showed narrow peaks at 2.8 and 4.7 ms. 5. On the basis of the present results it is concluded that the latency values of the step response represent the true sum of synaptic and axon dendritical propagation delay, whereas the latency of the responses to tone bursts also includes the temporal summation at the synaptic level.

High sound intensity by a two‐tube structure

1996 ◽  
Vol 100 (4) ◽  
pp. 2589-2590
Author(s):  
Ke Liu ◽  
Dah‐You Maa
Keyword(s):  
Sound Intensity ◽  
High Sound ◽  
Tube Structure

Numerical investigation of a honeycomb liner grazed by laminar and turbulent boundary layers

2016 ◽  
Vol 792 ◽  
pp. 936-980 ◽  
Author(s):  
Qi Zhang ◽  
Daniel J. Bodony
Keyword(s):  
Boundary Layers ◽  
Sound Field ◽  
Turbulent Boundary Layers ◽  
Pressure Amplitude ◽  
Sound Waves ◽  
Single Degree Of Freedom ◽  
Reduced Order ◽  
Impedance Model ◽  
Acoustic Liners ◽  
Orifice Flow

Direct numerical simulations are used to study the interaction of a cavity-backed circular orifice with grazing laminar and turbulent boundary layers and incident sound waves. The flow conditions and geometry are representative of single degree-of-freedom acoustic liners applied in the inlet and exhaust ducts of aircraft engines and are the same as those from experiments conducted at NASA Langley. The simulations identify the fluid mechanics of how the sound field and state of the grazing boundary layer impact the in-orifice flow and suggest a simple flow analogy that enables scaling estimates. From the scaling estimates the simulations are then used to develop reduced-order models for the in-orifice flow and a time-domain impedance model is constructed. The liner is found to increase drag at all conditions studied by an amount that increases with the incident sound pressure amplitude.

Quantifying Vocal Power: Correlation of Whole-Body Anaerobic Power to Vocal Function Measures

2020 ◽  
Vol 63 (8) ◽  
pp. 2597-2608
Author(s):  
Emily N. Snell ◽  
Laura W. Plexico ◽  
Aurora J. Weaver ◽  
Mary J. Sandage
Keyword(s):  
Fundamental Frequency ◽  
Forced Vital Capacity ◽  
Vital Capacity ◽  
Anaerobic Power ◽  
Performance Outcomes ◽  
Sound Level ◽  
Whole Body ◽  
Vocal Function ◽  
Laryngeal Diadochokinesis ◽  
High Sound

Purpose The purpose of this preliminary study was to identify a vocal task that could be used as a clinical indicator of the vocal aptitude or vocal fitness required for vocally demanding occupations in a manner similar to that of the anaerobic power tests commonly used in exercise science. Performance outcomes for vocal tasks that require rapid acceleration and high force production may be useful as an indirect indicator of muscle fiber complement and bioenergetic fitness of the larynx, an organ that is difficult to study directly. Method Sixteen women (age range: 19–24 years, M age = 22 years) were consented for participation and completed the following performance measures: forced vital capacity, three adapted vocal function tasks, and the horizontal sprint test. Results Using a within-participant correlational analyses, results indicated a positive relationship between the rate of the last second of a laryngeal diadochokinesis task that was produced at a high fundamental frequency/high sound level and anaerobic power. Forced vital capacity was not correlated with any of the vocal function tasks. Conclusions These preliminary results indicate that aspects of the laryngeal diadochokinesis task produced at a high fundamental frequency and high sound level may be useful as an ecologically valid measure of vocal power ability. Quantification of vocal power ability may be useful as a vocal fitness assessment or as an outcome measure for voice rehabilitation and habilitation for patients with vocally demanding jobs.

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