نتایج جستجو برای: other acoustic parameters such as sound velocity
تعداد نتایج: 6919982 فیلتر نتایج به سال:
To explore the acoustic characterization of composite solid propellant materials, wave equation viscoelastic body was derived based on linear constitutive model, and theoretical relationship between ultrasonic sound velocity attenuation coefficient, which are closely related to mechanical properties, such as elastic modulus, viscosity complex obtained. Ultrasonic air-coupled testing experiments...
Brillouin scattering experiments are carried out to study the surface acoustic waves in Nd0.5Sr0.5MnO3 as a function of temperature in the range of 40–300 K covering the metal-insulator and charge-ordering phase transitions. The surface modes include surface Rayleigh wave, pseudo-surface acoustic wave (PSAW) and high velocity PSAW. The observed softening of the sound velocities for the surface ...
The purpose of this article is to provide an analytical model of the vibroacoustic for an elastic beam submerged in low subsonic flows with mean velocities. In general, vibroacoustic modeling refers to the combined effects of sound propagation and mechanical vibration of the structure. Sound radiations from submerged structures are coupled with physical phenomena because the sound pressures act...
Introduction: In Iran country, there is a lack of reliable data on acoustic characteristics of building materials applied in the offices and industrial rooms. This study aimed to investigate noise absorption characteristics for current building and acoustics materials and provided the acoustic database. Method: In this cross sectional study, the minimum of 60 building and acoustic mate...
determination of uranium in natural water and complex solutions using ion exchange chromatography: a combined procedure using ion exchange chromatography and uv-vis spectrophotometry techniques has been developed to measure uranum in natural water and complex solutions. after conditicing , one hundred milli liters of sample solutions have been passed through an ion exchange column,pachked with ...
Background & Aims: Today, different imaging techniques have been studied in the reading of radiationsensitive polymer gels dosage. Due to limitations of imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT), ultrasound techniques are proposed for dose-dependent parameter extraction. In this study, using MAGIC-f (methacrylic and ascorbic acid in gelatin initiat...
This paper investigates acoustic wave propagation in gas-saturated permeable lossy metamaterials, which have different types of resonators, namely, and elastic as building-block elements. By using the two-scale asymptotic homogenization method, macroscopic equations that govern sound such metamaterials are established. These show can be modeled equivalent fluids with unconventional effective de...
ii abstract the legend of human being’s refulgence was distorted completely in the age of modernity. this new age, had some drastic negative effects, besides its positive qualities. one significant negative effect of it was the emergence of neurosis in human beings. aldous huxley’s brave new world was one of the novels of the 02 th century that contained the prophecy of criticizing ...
Sound sources can be localized and analysed using phased microphone arrays.Beamforming is a method for processing microphone array data to produce images that represent the distribution of the acoustic source strength.It is an imaging technique that applies to continuous or discrete source distribution.A microphone array can be designed to be more sensitive to the sound coming from one or more ...
The acoustic ducting effect by curved nonlinear gravity waves in shallow water is studied through idealized models in this paper. The internal wave ducts are three-dimensional, bounded vertically by the sea surface and bottom, and horizontally by aligned wavefronts. Both normal mode and parabolic equation methods are taken to analyze the ducted sound field. Two types of horizontal acoustic mode...
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