Advanced Search
Displaying 1-10 on page 1 of 61. Per Page  
  • Analytical Study on the Rate of Sound Transmission Loss in Single Row Honeycomb Sandwich Panel Using a Numerical Method
  • 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
  •   Views:460       Downloads:261        Download PDF
  • The Applications of Order Reduction Methods in Nonlinear Dynamic Systems
  • 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
  •   Views:468       Downloads:240        Download PDF
  • Using Audiometric Data to Weigh and Prioritize Factors that Affect Workers’ Hearing Loss through Support Vector Machine (SVM) Algorithm
  • 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
  •   Views:448       Downloads:231        Download PDF
  • Effect of Input Waveform to Vibration Speaker on Sound Quality of Electric Artificial Voice
  • 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
  •   Views:443       Downloads:251        Download PDF
  • Fixture Modifications for Effective Control of an Electrodynamic 3D-Shaker System
  • Abstract This work aims to improve the setup of an electrodynamic triaxial shaker prototype with respect to its usability for the automotive industry. Triaxial shakers being capable of meeting the corresponding requirements are not available as standard test equipment. Modifications on the fixture have to be conducted in order to ensure an effective control. The first part of the work is the qualitative description of the system behavior. Therefore, the shaker is treated as a black box. The second part is the modification of the test fixture in order to handle the resonances of the shaker, which is elementary for its…
  • More
  •   Views:461       Downloads:257        Download PDF
  • Implementation of a Biometric Interface in Voice Controlled Wheelchairs
  • Abstract In order to assist physically handicapped persons in their movements, we developed an embedded isolated word speech recognition system (ASR) applied to voice control of smart wheelchairs. However, in spite of the existence in the industrial market of several kinds of electric wheelchairs, the problem remains the need to manually control this device by hand via joystick; which limits their use especially by people with severe disabilities. Thus, a significant number of disabled people cannot use a standard electric wheelchair or drive it with difficulty. The proposed solution is to use the voice to control and drive the wheelchair instead…
  • More
  •   Views:632       Downloads:463        Download PDF
  • The Acoustic Performance of 3D Printed Multiple Jet Nozzles with Different Configurations
  • Abstract This work investigated multiple jet nozzles with various geometrical shape, number of exits, and material on reducing noise radiated from jet flows. Nozzles are categorized in two groups with few and many exit numbers, each with various exit shapes, slot and circular, and geometry. Firstly, nozzles are designed and then fabricated by a 3D printer, Form Labs, Form2USA, with polymeric resin. Also, the nozzle with the most noise reduction made of stainless steel. Noise and air thrust were measured at three air pressure gauges, 3, 5, 7 BAR and directions from nozzle apex, 30°, 90°, 135°. Nozzles with slot exit…
  • More
  •   Views:579       Downloads:521        Download PDF
  • Assessment of Traffic Noise Pollution in Burla Town, India; An Inclusive Annoyance Study
  • Abstract Noise pollution is one of the major public health problems in urban areas throughout the world. Noise is unwanted sound which produces undesirable problems in day to day life of human being (e.g., physiological and psychological problems). Rapid increase of the industrialization, urbanization, infrastructure, volume of motor vehicles, and increase in the road networks brought noise pollution to the highest level of disaster in a current situation. In urban areas, road traffic noise plays commanding role among all noise sources and affects the exposed inhabitants. The present work is done to evaluate and assess the traffic noise and its effects…
  • More
  •   Views:564       Downloads:379        Download PDF
  • Sound Signal Based Fault Classification System in Motorcycles Using Hybrid Feature Sets and Extreme Learning Machine Classifiers
  • 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
  •   Views:605       Downloads:344        Download PDF
Displaying 1-10 on page 1 of 61. Per Page