Free rotational aerophones such as the bullroarer, which consists of a wooden slat whirled around on the end of a string, and which emits a loud pulsating roar, have been used in many ancient and traditional societies for ceremonial purposes. This article presents an experimental and theoretical investigation of this instrument. The aerodynamics of rotational behavior is elucidated, and relates...

We obtained thirteen spectropolarimetric observations of the strongly magnetic rapidly oscillating Ap star HD154708 over three months with the multi-mode instrument FORS1, installed at the 8-m Kueyen telescope of the VLT. These observations have been used for the determination of the rotation period of P = 5.3666± 0.0007d. Using stellar fundamental parameters and the longitudinal magnetic field...

Consider that the sound dipole source in flow field is composed of multiple micro-spherical oscillating sources. An aerodynamic identification method established by relationship among source, radiated pressure, and pressure gradient near-wall field, formula for calculating power unsteady derived. It shows sources proportional to square force or gradient. The combination CFD further applied arou...

1 Raman Scattering Theory David W. Hahn Department of Mechanical and Aerospace Engineering University of Florida ([email protected]) Introduction The scattering of light may be thought of as the redirection of light that takes place when an electromagnetic (EM) wave (i.e. an incident light ray) encounters an obstacle or nonhomogeneity, in our case the scattering material (solid, liquid or gas). As...

this paper presents simplified hydrodynamics model for a biomimetic robot fish based on quantitative morphological and kinematic parameters of crangiform fish. the motion of four pangasius sanitwongsei with different length and swimming speed were recorded by the digital particle image velocimetry (dpiv) and image processing methods and optimal coefficients of the motion equations and appropria...

A hypothetical pseudoscalar particle axion, which is an immediate result of the Peccei-Quinn solution to strong $CP$ problem, may couple gluons and lead oscillating electric dipole moment (EDM) fundamental particles. This paper proposes a novel method probing axion-induced EDM in storage rings, using radio frequency (rf) Wien filter. The filter at sidebands axion $g\ensuremath{-}2$ frequency, $...

It has been shown that thin metal-based films can at certain frequencies act as planar near-field lenses for certain polarization components. A desirable property of such "lenses" is that they can also enhance and focus some large transverse spatial frequency components which contain sub-diffraction limit details. Over the last decade there has been much work in optimizing designs to reduce eff...

the need for clean groundwater resources to have sustainable development in a country is undoubted. due to the importance and high quality of karstic waters in supplying water in iran especially in shahrood city, it is attempted in this research work to recognize and explore karstic waters in southwest of tepal area, shahrood. for this purpose, integration of the results obtained from the metho...