Some acoustical properties of ships with respect to noise control

1962 ◽  
Vol 9 (97) ◽  
pp. 369-390
Author(s):  
J.H. Janssen
Keyword(s):  
Noise Control ◽  
Acoustical Properties

A hybrid method of predicting the acoustical properties of multi-layered materials

2021 ◽  
pp. 107754632110381
Author(s):  
Zechao Li ◽  
Lin Yang ◽  
Hongbin Ren ◽  
Sizhong Chen ◽  
Zheng Liu ◽  
...  
Keyword(s):  
Noise Control ◽  
Transmission Loss ◽  
Hybrid Approach ◽  
Sound Transmission ◽  
Normal Incidence ◽  
Layered Materials ◽  
Acoustical Properties ◽  
Transmission And Reflection Coefficients ◽  
Standing Wave Tube ◽  
Laminated Materials

Many numerical and measuring approaches are widely used in predicting and analysing the acoustic performances of laminated materials for noise control applications. However, numerical methods generally require a set of non-acoustic parameters, and the measuring methods are not available for exceedingly thick materials. The main aim of this article is to address a hybrid approach of evaluating the normal incidence sound transmission loss and absorption coefficients of multi-layered materials. This method is performed with some special parameters that contain the sound transmission and reflection coefficients of each sub-layer of a multi-layer specimen and can be measured by a standing wave tube system. The accuracy and feasibility of the present method are validated by the experimental and numerical comparisons between different methods and samples. Moreover, this present approach can be applied as a numerical tool of estimating the acoustical behaviours of multi-layered structures in noise control treatments, such as automotive, building and aerospace industries.

Noise control

1975 ◽  
Vol 54 (9) ◽  
pp. 458
Keyword(s):  
Noise Control

Acoustical Properties of Speech as Indicators of Depression and Suicidal Risk

2008 ◽  
Vol 4 ◽  
Author(s):  
Michael Joshua Landau
Keyword(s):  
Multiple Regression ◽  
Energy Band ◽  
Mental States ◽  
Cross Product ◽  
Female Group ◽  
Suicidal Risk ◽  
Energy Bands ◽  
Band Ratio ◽  
Acoustical Properties ◽  
Male Group

Acoustical properties of speech have been shown to be related to mental states such as remission and depression. The objective of this project was to relate the energy in frequency bands with the severity of the mental state using the Beck Depression Inventory (BDI). Recorded speech was obtained from male and female subjects with mental states of remission, depression, and suicidal risk. These subjects had recorded automated and spontaneous speech samples. Multiple regression analysis was used to relate the independent energy band ratio variables with the dependent BDI scores, and thus allow the determination of equitable BDI scores for future patients. For the male group, the square of the 3rd energy band and the cross-product of the 2nd and 3rd energy band were prominent in both the reading and interviewed groups. Therefore the equation with the 2nd lowest Akaike Information Criterion (AIC) score was chosen for the reading male group, and the 1st lowest AIC score was chosen for the interviewed male group. For the female group, the square and cross-product of the 1st and 2nd energy bands were prominent in both the reading and interviewed groups. Therefore the 2nd lowest AIC score was chosen for the reading female group, and the 1st lowest AIC score was chosen for the interviewed female group. The clinician could thus determine the patient’s mood or state of mind by comparing the estimated BDI score with the ranges of total BDI scores: remitted 0 – 20, depressed 15 – 38, suicidal 38 – 46. Keywords: speech, mental states, power spectra, multiple regression, information theoretic criterion

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