A. R. Mohanty^1,*, S. Fatima²

Sound & Vibration, Vol.54, No.4, pp. 247-256, 2020, DOI:10.32604/sv.2020.011011

Abstract This paper studies the acoustics of a frost free three door domestic refrigerator. Then, as a case study, the radiated noise reduction in the refrigerator using a natural material base composite is presented. Composites manufactured out of Jute, which is a plant fiber abundantly and cheaply available in India and Bangladesh are used in the noise reduction in the refrigerator. Mostly in this work, composites made out of felts of jute were used as barriers for noise control of the refrigerator. Measured acoustical, thermal and physical properties of various jute composites are reported. Noise sources in the refrigerator were characterized… More >

Mohammad Reza Ghotbi-Ravandi¹, Davoud Hassanvand², Sajad Zare^3,*, Milad Beytollahi⁴

Sound & Vibration, Vol.54, No.3, pp. 201-213, 2020, DOI:10.32604/sv.2020.08651

Abstract Undoubtedly, noise has become a major hazardous issue in today’s industrial world, with a lot of people suffering from exposure to excessive noise in their work environments. This study was conducted to weigh and prioritize noise control methods in an Iranian tire manufacturing complex in Iran. The Delphi method and the Technique for Order Preference by Similarity and an Ideal Solution (TOPSIS) were utilized for this purpose. This cross-sectional, descriptive study was conducted in the baking hall of an Iranian tire manufacturing factory in 2016. To weigh and prioritize noise control methods, Analytic Hierarchy Process (AHP) and TOPSIS were applied.… More >

Priyaranjan Pal^*

Sound & Vibration, Vol.54, No.3, pp. 179-200, 2020, DOI:10.32604/sv.2020.010679

Abstract This study determines the natural frequencies of the lock gate structure, considering the coupled effect of reservoir fluid on one side using the finite element method (FEM). The gate is assumed to be a uniformly thick plate, and its material is isotropic, homogeneous, and elastic. The reservoir fluid is assumed to be inviscid and incompressible in an irrotational flow field. The length of the reservoir domain is truncated using the far boundary condition by adopting the Fourier series expansion theory. Two different assumptions on the free surface, i.e., undisturbed and linearized, are considered in the fluid domain analysis. The computer… More >

Parvane Mahdi¹, Akram Pourbakht^1,*, Vahid Pirhajati Mahabadi², Alireza Karimi Yazdi³, Mahtab Rabbani Anari³, Mohammad Kamali⁴

Sound & Vibration, Vol.54, No.3, pp. 163-177, 2020, DOI:10.32604/sv.2020.09880

Abstract Exposure to high level of noise, may cause the permanent cochlear synaptic degeneration. In present study, a model of noise induced cochlear synaptopathy was established and the electrophysiological and histological metrics for its assessment was designed. 6 guinea pigs were subjected to a synaptopathic noise (octave band of 4 kHz at 104 dB SPL, for 2-h). The amplitude growth curve of Auditory Brainstem Response (ABR) wave-I and wave-III latency shift in presence of noise were calculated. These indexes were considered in pre-exposure, 1 day post exposure (1DPE), 1 week post exposure (1WPE) and 1 month post exposure (1MPE) to noise.… More >

Y. A. Amer¹, A. T. El-Sayed², M. N. Abd El-Salam^3,*

Sound & Vibration, Vol.54, No.3, pp. 149-161, 2020, DOI:10.32604/sv.2020.08469

Abstract In this paper, we used time delay feedback to minimize the vibrations of a hybrid Rayleigh–van der Pol–Duffing oscillator. This system is a one-degree-offreedom containing the cubic and fifth nonlinear terms and an external force. We applied the multiple scales method to get the solution from first approximation. Graphically and numerically, we studied the system before and after adding time delay feedback at the primary resonance case (Ω ≌ ω). We used MATLAB program to simulate the efficacy of different parameters and the time delay on the main system. More >

Hossein Molaeifar¹, Farahnaz Khajehnasiri², Kiana Nikeghbal³, Zahra Zamanian^1,*

Sound & Vibration, Vol.54, No.3, pp. 139-148, 2020, DOI:10.32604/sv.2020.08810

Abstract Exposure to sound, heat, and increased physical workload can change physiological parameters. This study was conducted to evaluate the effect of concomitant exposure to sound, heat, and physical workload changes on physiological parameters in controlled laboratory conditions. This experimental crosssectional study was conducted in 35 male university students with a mean age of 25.75 years and a mean BMI of 22.69 kg/m² . Systolic and diastolic blood pressure and heart rate were measured after 15 min rest in the laboratory, 5 and 10 min after starting the experiment, and then after 20 min in controlled laboratory conditions in five combination… More >

Rohollah Fallah Madvari¹, Mohammad Reza Monazzam², Mohsen Niknam Sharak³, Mohsen Mosa Farkhani^4,*

Sound & Vibration, Vol.54, No.2, pp. 127-137, 2020, DOI:10.32604/sv.2020.08158

Abstract Honeycomb structures have recently, replaced with conventional homogeneous materials. Given the fact that sandwich panels containing a honeycomb core are able to adjust geometric parameters, including internal angles, they are suitable for acoustic control applications. The main objective of this study was to obtain a transmission loss curve in a specific honeycomb frequency range along with same overall dimensions and weight. In this study, a finite element model (FEM) in ABAQUS software was used to simulate honeycomb panels, evaluate resonant frequencies, and for acoustic analysis. This model was used to obtain acoustic pressure and then to calculate the sound transmission… More >

Nan Wu^1,#, Kuan Lu^1,2,#,*, Yulin Jin^2,3,*, Haopeng Zhang¹, Yushu Chen²

Sound & Vibration, Vol.54, No.2, pp. 113-125, 2020, DOI:10.32604/sv.2020.09783

Abstract Two different order reduction methods of the deterministic and stochastic systems are discussed in this paper. First, the transient proper orthogonal decomposition (T-POD) method is introduced based on the high-dimensional nonlinear dynamic system. The optimal order reduction conditions of the T-POD method are provided by analyzing the rotor-bearing system with pedestal looseness fault at both ends. The efficiency of the T-POD method is verified via comparing with the results of the original system. Second, the polynomial dimensional decomposition (PDD) method is applied to the 2 DOFs spring system considering the uncertain stiffness to study the amplitude-frequency response. The numerical results… More >

Hossein ElahiShirvan¹, MohammadReza Ghotbi-Ravandi², Sajad Zare^3,*, Mostafa Ghazizadeh Ahsaee⁴

Sound & Vibration, Vol.54, No.2, pp. 99-112, 2020, DOI:10.32604/sv.2020.08839

Abstract Workers’ exposure to excessive noise is a big universal work-related challenges. One of the major consequences of exposure to noise is permanent or transient hearing loss. The current study sought to utilize audiometric data to weigh and prioritize the factors affecting workers’ hearing loss based using the Support Vector Machine (SVM) algorithm. This cross sectional-descriptive study was conducted in 2017 in a mining industry in southeast Iran. The participating workers (n = 150) were divided into three groups of 50 based on the sound pressure level to which they were exposed (two experimental groups and one control group). Audiometric tests… More >

T. Asakura^*, K. Shindo

Sound & Vibration, Vol.54, No.2, pp. 85-98, 2020, DOI:10.32604/sv.2020.08119

Abstract A number of studies have been conducted on the improvement of the sound quality of electrical artificial laryngeal speech, the speech produced has been difficult to hear compared to a natural voice. For this reason, it is necessary to effectively improve the frequency characteristics of the input signal. In the present study, to improve the sound quality of vocalization using an electrical artifi- cial larynx, first, a comparison of the frequency characteristics between the real and artificial voices was conducted, and three filters that can make the frequency characteristics of the artificial voice closer to those of a real voice… More >