In this work, we propose the generation of diffraction-resistant beams by using a parabolic reflector and a source of spherical waves positioned at a point slightly displaced from its focus (away from the reflector). In our analysis, considering the reflector dimensions much greater than the wavelength, we describe the main characteristics of the resulting beams, showing their properties of res...

We have been successful in developing light and durable mirrors made of CFRP (Carbon Fiber Reinforced Plastic) laminates for the reflector of the new CANGAROO-II 7 m telescope. The reflector has a parabolic shape (F/1.1) with a 30 m effective area which consists of 60 small spherical mirrors of CFRP laminates. The orientation of each mirror can be remotely adjusted by stepping motors. After the...

We presented the investigation of broadband metamaterial reflector for polarization manipulation based on cross/ring resonators. It is demonstrated that the metamaterial reflector can convert the linearly polarized incident wave to its cross polarized wave or circularly polarized wave. Due to the multiple resonances at neighboring frequencies, the proposed reflector presents broadband property ...

Many students first learn of the law of reflection when they are told about the reflective properties of conics. Typically students are exposed to a curve or surface, and then its reflective properties are derived or verified. In this paper we explore reflection by starting from a desired property of an unknown reflector and proceeding to find a reflector with those properties. This is done in ...

Twist extrusion process is a rather new route to produce highly strained materials. In this process, severe plastic deformation is applied by large shear strains. In current article, required energy for twist extrusion by use of admissible velocity field together with the upper bound technique is predicted. The proposed model is capable of considering the effect of various parameters such as di...

We propose a fast algorithm to estimate the flux collected by conic reflector patches, based on the calculation of intersections between neighboring patches. The algorithm can be employed in conjunction with the supporting ellipsoids algorithm for freeform reflector design and is shown to be orders of magnitude faster and more scalable than the commonly used Monte Carlo ray tracing approach.

The acoustic pressure field of an electrohydraulic extracorporeal shock wave lithotripter is modeled with a nonlinear parabolic wave equation (the KZK equation). The model accounts for diffraction, nonlinearity, and thermoviscous absorption. A numerical algorithm for solving the KZK equation in the time domain is used to model sound propagation from the mouth of the ellipsoidal reflector of the...

In the present work an attempt has been made to study the effect of the twisted tapes as bed internals, on the performance of the gas-solid fluidized beds. Experimental investigation has been carried out in cylindrical column with and without twisted tapes. Twelve numbers of twisted tapes of three different widths with four values of the twist ratios for each width were studied at different...

Background: The aim of the present study was to evaluate how left ventricular twist and torsion are associated with sex between sex groups of the same age.Materials and Methods: In this analytical study, twenty one healthy subjects were scanned in left ventricle basal and apical short axis views to run the block matching algorithm; instantaneous changes in the base and apex rotation angel...