In consideration of physical and chemical properties of pure substances, speed of sound is one of important quantity which can used to calculate many of other thermo-physical properties such as isothermal compressibility, Joule-Thomson coefficient, isobaric heat capacity and etc. These thermo-physical properties are the main parameters in industrial and chemical processes. Development of accura...

We study Dirac-Born-Infeld inflation models with multiple scalar fields. We show that the adiabatic and entropy modes propagate with a common effective sound speed and are thus amplified at the sound horizon crossing. In the small sound speed limit, we find that the amplitude of the entropy modes is much higher than that of the adiabatic modes. We show that this could strongly affect the observ...

thermophysical properties of fluorine are interesting because of its applications in different areas of technologyand industry. the computations of thermodynamic properties were performed with the gma equation of stateunder critical conditions. the present work reports calculations of density, volumetric, and thermodynamicproperties of liquid fluorine on extended ranges of pressure and temperat...

Granular materials are inherently heterogeneous, leading to challenges in formulating accurate models of sound propagation. In order to quantify acoustic responses in space and time, we perform experiments in a photoelastic granular material in which the internal stress pattern (in the form of force chains) is visible. We utilize two complementary methods, highspeed imaging and piezoelectric tr...

A sound wave traveling in air causes oscillations in pressure above or below the ambient atmospheric pressure. In acoustic theory, a sound source is mainly characterized by its amplitude and frequency (f). The acoustic incident pressure field (p̃) at an observation point, x, due to a point source located at xs is given by Equation 1 where, ω = 2πf , c0 is the speed of sound and S̃ represents the ...

background: one of the most widely used equipments in harvesting hay and grains are four wheel mowers. the aim of the present study was to determine the levels of noise exposure in drivers and bystanders in different states, speeds and gear of four wheel mowers (bcs model 622).   methods: the iso 5131 and iso 6814 standards were used to assess noise exposure in drivers and bystanders, respectiv...

Wind turbine (WT) sound annoys some people even though the sound levels are relatively low. This could be because of the amplitude modulated "swishing" characteristic of the turbine sound, which is not taken into account by standard procedures for measuring average sound levels. Studies of sound immission from WTs were conducted continually between 19 August 2011 and 19 August 2012 at two sites...

abstract- noise is considered as one of the most debilitating conditions in farming operations. in this study, a number of factors affecting the noise generated by sampo 3065 combine harvesters were evaluated. factors were engine speed and gear ratio for combines with and without original cabins. a factorial experiment arranged as a completely randomized design with four replicates was used. re...

Abstract Background: Opium-dependence having different effects on the nervous system is a common problem, especially in the Middle East and Iran. The aim of this study is evaluating the effects of opium-dependence on visual evoked potential (VEP) in men. Methods: Thirty subjects with both chronic cigarette smoking and opium-dependence (group 1) and 30 subjects with only chronic ciga...