scholarly journals Experimental/Numerical Acoustic Assessment of Aircraft Seat Headrests Based on Electrospun Mats

2021 ◽  
Vol 11 (14) ◽  
pp. 6400
Author(s):  
Venanzio Giannella ◽  
Claudio Colangeli ◽  
Jacques Cuenca ◽  
Roberto Citarella ◽  
Mattia Barbarino
Keyword(s):  
Boundary Element Method ◽  
Experimental Validation ◽  
Sound Pressure ◽  
Pressure Level ◽  
Parallel Simulations ◽  
Aircraft Cabin ◽  
Acoustic Comfort ◽  
Set Up ◽  
Passenger Aircraft ◽  
Passive Noise

The work proposes a methodology for the assessment of the performances of Passive Noise Control (PNC) for passenger aircraft headrests with the aim of enhancing acoustic comfort. Two PNC improvements of headrests were designed to reduce the Sound Pressure Level (SPL) at the passengers’ ears in an aircraft cabin during flight; the first was based on the optimization of the headrest shape, whereas the second consisted of partially or fully covering the headrest surface with a new highly sound-absorbing nanofibrous textile. An experimental validation campaign was conducted in a semi-anechoic chamber. A dummy headrest was assembled in different configurations of shape and materials to assess the acoustic performances associated to each set up. In parallel, simulations based on the Boundary Element Method (BEM) were performed for each configuration and an acceptable correlation between experimental and numerical results was obtained. Based on these findings, general guidelines were proposed for the acoustical design of advanced headrests.

scholarly journals Acoustic Improvements of Aircraft Headrests Based on Electrospun Mats Evaluated Through Boundary Element Method

2020 ◽  
Vol 10 (16) ◽  
pp. 5712
Author(s):  
Venanzio Giannella ◽  
Francesco Branda ◽  
Jessica Passaro ◽  
Giuseppe Petrone ◽  
Mattia Barbarino ◽  
...  
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Sound Pressure ◽  
Pressure Level ◽  
Cabin Noise ◽  
Acoustic Load ◽  
Acoustic Comfort ◽  
Passive Noise ◽  
The Impact ◽  
Element Method

This work illustrates the development of passive noise control (PNC) improvements of aircraft headrests to enhance the acoustic comfort for passengers. Two PNC improvements were studied with the aim of reducing the noise perceived by passengers during flight. Two headrest configurations, with and without the lateral caps, and two different materials, a traditional foam and an innovative Silica/Polyvinylpyrrolidone (PVP) woven non-woven mat, were considered, and compared in terms of sound pressure level (SPL) perceived by passengers. Boundary element method (BEM) models were built up to evaluate the acoustic performances of different headrest configurations, varying in terms of shape and textile. A spherical distribution of monopole sources surrounding the headrests was considered as acoustic load, in such a way as to recreate a diffuse acoustic field simulating the cabin noise perceived by passengers during cruise conditions. The impact of the two PNC improvements was analyzed to envisage some general guidelines useful to design advanced headrests from the acoustic viewpoint.

Development of Method for Measurement Sound Pressure Level to Use Earphone

2013 ◽  
Vol 717 ◽  
pp. 378-383
Author(s):  
Seok Hoon Kang ◽  
Hyuk Moon
Keyword(s):  
Hard Of Hearing ◽  
Sound Pressure ◽  
Measured Data ◽  
Pressure Level ◽  
Experimental Equipment ◽  
Warning Message ◽  
The Hours ◽  
Set Up ◽  
And Control ◽  
Widespread Dissemination

Earphone use has skyrocketed due to the widespread dissemination of portable acoustic-apparatus. As the result, hearing loss due to noise-induced is becoming a big social problem. As the existing method, warning message is only used to prevent the hard of hearing according to the earphone use. However, it is hard for users to know the effect of the hours of earphone use and volume on their hearing, and control the earphone use by themselves. Therefore, in this paper, the method is suggested that users measure the effect of the time and volume of earphone use on their hearing with the simple experimental equipment and program. The method suggested in this paper is based on the simple experimental equipment to set up the similar environment to the real ear, and the program to find out the effect on hearing with the measured data.

The Exploration of Evaluation Method about the Driving Electromotor Acoustic Comfort of the Pure Electric Vehicles

2012 ◽  
Vol 224 ◽  
pp. 113-118
Author(s):  
Ming Liang Yang ◽  
Wei Ping Ding
Keyword(s):  
Electric Vehicles ◽  
Sound Pressure ◽  
Evaluation Method ◽  
Pressure Level ◽  
High Fidelity ◽  
Subjective Testing ◽  
Electric Bus ◽  
Acoustic Comfort ◽  
Dual Channels ◽  
Noise Sample

The driving electromotor noise of a pure electric bus was taken as the evaluation object in this paper. The noise signals were gathered by dual channels and to simulating human auditory by synthetic stereo, and were processed into a series of noise samples for human subjective testing generated according to the 3dB differential progressive attenuation of noise sound pressure level. Then the author investigated the human body comfort/discomfort subjective feelings under various noise samples through the high fidelity audio playback, described the subjective feelings with ‘descriptor’, and quantified the subjective feelings with scores at the same time. On this basis, the correlation of subjective feelings between acoustic comfort and discomfort were revealed, and the noise sample sets corresponding with comfort feeling were found out. Based on these, an evaluation method of electromotor acoustic comfort was established.

scholarly journals Determination of thermal and acoustic comfort inside a vehicle’s cabin

2018 ◽  
Vol 32 ◽  
pp. 01002
Author(s):  
Alexandra Ene ◽  
Tiberiu Catalina ◽  
Andreea Vartires
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
The Other ◽  
Air Velocity ◽  
Acoustic Comfort ◽  
Comfort Parameters

Thermal and acoustic comfort, inside a vehicle’s cabin, are highly interconnected and can greatly influence the health of the passengers. On one hand, the H.V.A.C. system brings the interior air parameters to a comfortable value while on the other hand, it is the main source of noise. It is an intriguing task to find a balance between the two. In this paper, several types of air diffusers were used in order to optimize the ratio between thermal and acoustic interior comfort. Using complex measurements of noise and thermal comfort parameters we have determined for each type of air diffuser the sound pressure level and its impact on air temperature and air velocity.

A Numerical Study of the Diffusion Performance of a Terraced Classroom

2011 ◽  
Vol 97 (5) ◽  
pp. 890-899
Author(s):  
Zhaorong Zhang ◽  
C. M. Mak ◽  
Jianliang Li
Keyword(s):  
Boundary Element Method ◽  
Porous Material ◽  
Sound Wave ◽  
Sound Pressure ◽  
Numerical Study ◽  
Quadratic Residue ◽  
Pressure Level ◽  
Two Dimensional ◽  
Rear Wall ◽  
Dimensional Boundary

The acoustic diffusion performance of a terraced classroom was investigated using a two-dimensional boundary element method. Quadratic residue diffuser (QRD) and porous material were employed on the ceiling and rear wall, respectively, to improve the diffusion performance. The diffusion gains of various models were calculated to compare the diffusion performance. It is found that terraces in a rectangular classroom raise the lowest sound pressure level and provide slight diffusion improvement. The QRD ceiling enhances the diffusion by scattering the sound wave to be more evenly distributed, but at some frequencies the diffusion improvement is minor or even negative. The absorption rear wall provides useful diffusion gain mainly at higher frequencies by absorbing parts of the reflected sound. When the parameters of the QRD ceiling and porous material change, the diffusion improvement first increases and then begins to decrease. In a terraced classroom with both treatments, the diffusion at lower frequencies is similar to that with the QRD ceiling, while at higher frequencies it resembles that with the absorption rear wall. The results clearly indicate that the combination of the two treatments produces the most desirable diffusion performance of the tested models.

Evaluation of floating floors performances using the reception plate method

2021 ◽  
Vol 263 (5) ◽  
pp. 1911-1918
Author(s):  
Fabio Serpilli ◽  
Valter Lori ◽  
Samantha Di Loreto
Keyword(s):  
Experimental Validation ◽  
Sound Pressure ◽  
Plate Theory ◽  
Power Level ◽  
Pressure Level ◽  
Plate Method ◽  
Sound Power Level ◽  
Simplified Method ◽  
The Impact ◽  
Level Reduction

This paper concerns the development and experimental validation of a simplified method to evaluate the performances of materials for floating floors. The method is based on the reception plate theory. The porpouse is to evaluate the impact sound pressure level reduction ΔL by the differences of the sound power level ΔP measured on the reception plate with and without the acoustic material. The results are compared with the values measured in accordance with ISO 10140 standards.

scholarly journals Studies on acoustic comfort in a passive house

2019 ◽  
Vol 111 ◽  
pp. 06080
Author(s):  
Catalin Bailescu ◽  
Tiberiu Catalina ◽  
Vlad Iordache
Keyword(s):  
Sound Pressure Level ◽  
Heat Recovery ◽  
Sound Pressure ◽  
Pressure Level ◽  
Passive House ◽  
Circulation Pump ◽  
Absorbent Material ◽  
Functional Parameters ◽  
Acoustic Comfort ◽  
Specialized Equipment

Acoustic comfort is a requirement of major importance during the design of houses. This study focused on the acoustic comfort parameter called sound pressure level. The value of this parameter is variable during operation of a particular building , depending on the type of absorbent material and them surface. The aim of this study is to determine the influence of the equipment of the technical space for a passive house . In this study was experimentally determined the value of noise for a Passive House in Romania using specialized equipment and software from Bruel & Kjaer . With these equipment and software were simulated different functional parameters of heat recovery and circulation pump, and different ways of placing the house on various types of roads leading sound pressure level simultaneously for five rooms , result compared with rules imposed values for each type of room.

Contributions of Voice and Nonverbal Communication to Perceived Masculinity–Femininity for Cisgender and Transgender Communicators

2020 ◽  
Vol 63 (4) ◽  
pp. 931-947
Author(s):  
Teresa L. D. Hardy ◽  
Carol A. Boliek ◽  
Daniel Aalto ◽  
Justin Lewicke ◽  
Kristopher Wells ◽  
...  
Keyword(s):  
Fundamental Frequency ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Vocal Tract ◽  
Presentation Mode ◽  
Pressure Level ◽  
Presentation Modes ◽  
Audiovisual Stimuli ◽  
Vocal Tract Resonance ◽  
Point Light

Purpose The purpose of this study was twofold: (a) to identify a set of communication-based predictors (including both acoustic and gestural variables) of masculinity–femininity ratings and (b) to explore differences in ratings between audio and audiovisual presentation modes for transgender and cisgender communicators. Method The voices and gestures of a group of cisgender men and women ( n = 10 of each) and transgender women ( n = 20) communicators were recorded while they recounted the story of a cartoon using acoustic and motion capture recording systems. A total of 17 acoustic and gestural variables were measured from these recordings. A group of observers ( n = 20) rated each communicator's masculinity–femininity based on 30- to 45-s samples of the cartoon description presented in three modes: audio, visual, and audio visual. Visual and audiovisual stimuli contained point light displays standardized for size. Ratings were made using a direct magnitude estimation scale without modulus. Communication-based predictors of masculinity–femininity ratings were identified using multiple regression, and analysis of variance was used to determine the effect of presentation mode on perceptual ratings. Results Fundamental frequency, average vowel formant, and sound pressure level were identified as significant predictors of masculinity–femininity ratings for these communicators. Communicators were rated significantly more feminine in the audio than the audiovisual mode and unreliably in the visual-only mode. Conclusions Both study purposes were met. Results support continued emphasis on fundamental frequency and vocal tract resonance in voice and communication modification training with transgender individuals and provide evidence for the potential benefit of modifying sound pressure level, especially when a masculine presentation is desired.

Influence of the Acoustic Reflex on Vowel Recognition

1986 ◽  
Vol 29 (3) ◽  
pp. 420-424 ◽  
Author(s):  
Michael Dorman ◽  
Ingrid Cedar ◽  
Maureen Hannley ◽  
Marjorie Leek ◽  
Julie Mapes Lindholm
Keyword(s):  
Auditory System ◽  
Sound Pressure ◽  
Dynamic Range ◽  
Recognition Accuracy ◽  
Pressure Level ◽  
Acoustic Reflex ◽  
The Poor ◽  
Stapedial Reflex ◽  
Vowel Recognition ◽  
High Sound

Computer synthesized vowels of 50- and 300-ms duration were presented to normal-hearing listeners at a moderate and high sound pressure level (SPL). Presentation at the high SPL resulted in poor recognition accuracy for vowels of a duration (50 ms) shorter than the latency of the acoustic stapedial reflex. Presentation level had no effect on recognition accuracy for vowels of sufficient duration (300 ms) to elicit the reflex. The poor recognition accuracy for the brief, high intensity vowels was significantly improved when the reflex was preactivated. These results demonstrate the importance of the acoustic reflex in extending the dynamic range of the auditory system for speech recognition.

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