Vikas S. Hakke¹, Uday D. Bagale¹, Sami Boufi², G. Uday Bhaskar Babu¹, Shirish H. Sonawane^1,*

Journal of Renewable Materials, Vol.8, No.3, pp. 239-250, 2020, DOI:10.32604/jrm.2020.08449

Abstract Starch nanocrystals (SNC) were prepared from maize starch using ultrasound assisted acid hydrolysis. The process takes less time for the generation of SNC, which is advantageous over conventional acid hydrolysis. The synthesized SNC were characterized using X-ray diffraction, dynamic light scattering, zeta potential and transmission electron microscopy (TEM). Particle size and TEM data show that the particles were near to 150 nm, with oval morphology. The SNC with higher surface charge are obtained with this innovative approach as compared to conventional acid hydrolysis. Because of high surface charge and oval like morphology, the SNC performed well in reinforcing a polyurethane… More >

T. Jayasree^1,*, R. Prem Ananth²

Sound & Vibration, Vol.54, No.1, pp. 57-74, 2020, DOI:10.32604/sv.2020.08573

Abstract Vehicles generate dissimilar sound patterns under different working environments. These generated sound patterns signify the condition of the engines, which in turn is used for diagnosing various faults. In this paper, the sound signals produced by motorcycles are analyzed to locate various faults. The important attributes are extracted from the generated sound signals based on time, frequency and wavelet domains which clearly describe the statistical behavior of the signals. Further, various types of faults are classified using the Extreme Learning Machine (ELM) classifier from the extracted features. Moreover, the improved classification performance is obtained by the combination of feature sets… More >

Parvin Nassiri¹, Sajad Zare^2,*, Mohammad Reza Monazzam¹, Akram Pourbakht³, Rasoul Hemmatjo⁴, Hossein ElahiShirvan²

Sound & Vibration, Vol.54, No.1, pp. 17-25, 2020, DOI:10.32604/sv.2020.08395

Abstract Exposure to noise can lead to anatomical, nonauditory, and auditory impacts. The auditory influence of noise exposure is manifested in the form of Noise-induced hearing loss (NIHL). The current study aimed at present a signal to noise ratio model of otoacoustic emission of rats’ ears in the light of the combined effect of sound pressure level, sound frequency, exposure time, and potassium concentration of the used water. In total, 36 adult male rates, whose age varied from 3 to 4 months and had a weight of 200 ± 50 g, were randomly divided into 12 groups, with each group consisting… More >

Narsimha Pandi¹, Shirish H. Sonawane^1,*, Sarang P. Gumfekar², Anand Kishore Kola¹, Pramod H. Borse³, Swapnil B. Ambade⁴, Sripadh Guptha¹, Muthupandian Ashokkumar⁵

Journal of Renewable Materials, Vol.7, No.12, pp. 1279-1293, 2019, DOI:10.32604/jrm.2019.07609

Abstract The present study deals with the intensified synthesis of starchpolyaniline (starch-PANI) nanocomposite using an ultrasound-assisted method. Starch is a key component in this nanocomposite, which acts as a backbone of the nucleation of PANI. The Electrochemical property of the nanocomposite arises due to the addition of PANI. This is one of green approach for the synthesis of bio nanocomposite using ultrasound. The crystallinity of the composite is evaluated using the Scherrer Formula. The starch-PANI nanocomposite was characterized by XRD, FT-IR, Raman, XPS and TEM. The composite nanoparticles show spherical morphology. The elemental composition of starch-PANI showed O 1s peak at… More >

Roohalah Hajizadeh¹, Ali Khavanin^2,*, Mohammad Barmar³, Ahmad Jonidi Jafari⁴, Somayeh Farhang Dehghan⁵

Sound & Vibration, Vol.53, No.5, pp. 207-222, 2019, DOI:10.32604/sv.2019.06523

Abstract Polyurethane foam as the most well-known absorbent materials has a suitable absorption coefficient only within a limited frequency range. The aim of this study was to improve the sound absorption coefficient of flexible polyurethane (PU) foam within the range of various frequencies using clay nanoparticles, polyacrylonitrile nanofibers, and polyvinylidene fluoride nanofibers. The response surface method was used to determine the effect of addition of nanofi- bers of PAN and PVDF, addition of clay nanoparticles, absorbent thickness, and air gap on the sound absorption coefficient of flexible polyurethane foam (PU) across different frequency ranges. The absorption coefficient of the samples was… More >

S.Mohanty¹, A. Chattopadhyay², J. Wei³, P. Peralta⁴

Structural Durability & Health Monitoring, Vol.5, No.3, pp. 227-250, 2009, DOI:10.3970/sdhm.2009.005.227

Abstract This paper proposes unsupervised system identification based methods to estimate time-series fatigue damage states in real-time. Ultrasound broadband input is used for active damage interrogation. Novel damage index estimation techniques based on dual sensor signals are proposed. The dual sensor configuration is used to remove electrical noise, as well as to improve spatial resolution in damage state estimation. The scalar damage index at any particular damage condition is evaluated using nonparametric system identification techniques, which includes an empirical transfer function estimation approach and a correlation analysis approach. In addition, the effectiveness of two sensor configurations (configuration 1: sensors placed near… More >

Aleš Belšak¹, Jurij Prezelj²

Structural Durability & Health Monitoring, Vol.3, No.4, pp. 239-246, 2007, DOI:10.3970/sdhm.2007.003.239

Abstract Noise source vizualization represents an important tool in the field of technical acoustics. There are many different techniques of noise source visualization. Most of them, however, are intended for a specific noise source in a specific type of acoustic environment. Consequently, a certain visualization method can be used only for certain types of noise sources in a specific acoustic environment and in a restricted frequency area. This paper presents a new visualization method of complex noise sources on the basis of the use of an acoustic camera. A new algorithm has been used, which makes it possible to visualize all… More >

Lamia Bouafif¹, Noureddine Ellouze²

Sound & Vibration, Vol.52, No.6, pp. 2-10, 2018, DOI:10.32604/sv.2018.02410

Abstract Sound indexing and segmentation of digital documents especially in the internet and digital libraries are very useful to simplify and to accelerate the multimedia document retrieval. We can imagine that we can extract multimedia files not only by keywords but also by speech semantic contents. The main difficulty of this operation is the parameterization and modelling of the sound track and the discrimination of the speech, music and noise segments. In this paper, we will present a Speech/Music/Noise indexing interface designed for audio discrimination in multimedia documents. The program uses a statistical method based on ANN and HMM classifiers. After… More >

Qian Kong¹, Genshan Jiang^{1, 2, *}, Yuechao Liu¹

Sound & Vibration, Vol.52, No.4, pp. 9-20, 2018, DOI:10.32604/sv.2018.03749

Abstract The temperature field distribution directly reflects the combustion condition in a furnace．In this paper, acoustic thermometry to reconstruct temperature distribution is investigated. A method based on radial basis function approximation with polynomial reproduction (RBF-PR) is proposed in order to improve the accuracy and stability of the method based on RBF approximation. In addition, the refraction effect of sound wave paths is considered in the process of reconstruction. The curved lines with refraction effect are numerically calculated by solving differential equations, which show that sonic waves curve towards the zones of higher temperature. The reconstructed performance is validated via numerical simulation… More >

Guangzheng Yu^1,*, Yu Liu^1,2, Bosun Xie¹, Huali Zhou¹

Sound & Vibration, Vol.53, No.4, pp. 151-159, 2019, DOI:10.32604/sv.2019.04644

Abstract To accelerate head-related transfer functions (HRTFs) measurement, two or more independent sound sources are usually employed in the measurement system. However, the multiple scattering between adjacent sound sources may influence the accuracy of measurement. On the other hand, the directivity of sound source could induce measurement error. Therefore, a model consisting of two spherical sound sources with approximate omni-directivity and a rigid-spherical head is proposed to evaluate the errors in HRTF measurement caused by multiple scattering between sources. An example of analysis using multipole re-expansion indicates that the error of ipsilateral HRTFs are within the bound of ± 1.0 dB… More >