The standard definition of cylindrical symmetry in General Relativity is reviewed. Taking the view that axial symmetry is an essential pre-requisite for cylindrical symmetry, it is argued that the requirement of orthogonal transitivity of the isometry group should be dropped, this leading to a new, more general definition of cylindrical symmetry. Stationarity and staticity in cylindrically symm...

In this paper, we implement finite volume Weighted Essentially Non-Oscillatory (WENO) schemes in both cylindrical and spherical coordinate systems for the Euler equations with cylindrical or spherical symmetry. We analyze three different spatial discretizations: one that is shown to be high-order accurate but not conservative, one conservative but not high-order accurate, and one both high-orde...

Introduction: There has been a curiosity about the spheroid geometry for PET scanners developments since several years ago, therefore in this study, we are aiming to evaluate the performance of this geometry and compare its performance with cylindrical geometry using Monte Carlo simulation. Methods: We simulated a spheroid geometry with a radius of 199 mm...

A line-focus ultrasonic SH-wave probe is developed for possible application to TOFD method. The probe is composed of a quarteror half-cylindrical wedge and a piezoelectric transducer adhered to the cylindrical surface of the wedge. An SH-wave pulse with cylindrical wave front is generated by the transducer, transmitted to the wedge, and focused on a line at the bottom surface of the wedge. Henc...

Cylindrical Wiener processes in real separable Banach spaces are defined, and an approximation theorem involving scalar Wiener processes is given for such processes. A weak stochastic integral for Banach spaces involving a cylindrical Wiener process as integrator and an operator-valued stochastic process as integrand is defined. Basic properties of this integral are stated and proved. A class o...

A compact dual-band antenna made of high dielectric constant substrate is studied. Embedding a higher dielectric cylindrical inside the substrate host cylindrical enhances the dual-band behaviour. The first part displays the characteristics of single CRDA as return loss, bandwidth and radiation pattern, then, the second part describes the aim of using an antenna, composed by the arrangement of ...

Lateral tape motion (LTM) is a function of tape path and tape properties, design parameters such as speed, tension, and friction between tape and tape path components. This investigation deals with the LTM of a tape moving over the surface of a cylindrical guide. Starting from the equation of motion for a moving tape on a cylindrical guide surface, the effects of friction, tape properties and d...

Abstract—The patch shape influence on the radar cross section (RCS) of a cylindrical microstrip antenna (CMA) is discussed. The RCS of the CMA is evaluated from a plane wave scattering problem solution to a cylindrical microstrip antenna. The method of moments is employed in the spectral domain using sub-domain basis functions. It is shown that the patch shape has a pronounced effect such that ...

The vibro-acoustic characteristics of cylindrical shell are widely studied because of its strong engineering application background, especially when the shell is immersed in infinite fluid field or partially immersed. In the present paper, the method for analyzing sound radiation of semi-submerged finite cylindrical shell with antisymmetric velocity distribution is first proposed. The orthogona...

In the reconstruction of cylindrical phase-only hologram (POH), speckle noise caused by addition random phase is rarely discussed. Although some suppression algorithms have been proposed for planar POH, it does not work well if they are directly applied to POH. To solve this issue, self-diffraction iteration (CSDI) algorithm proposed. This an based on model which a special case backward-propaga...