We show that an electromagnetic (EM) wave undergoes negative refraction at the interface between a positive and negative refractive index material, the latter being a properly chosen photonic crystal. Finite-difference time-domain (FDTD) simulations are used to study the time evolution of an EM wave as it hits the interface. The wave is trapped temporarily at the interface, reorganizes, and, af...

This paper describes the design of a direct-drive permanent-magnet generator for use in a novel sea-wave electrical generator. The basic system is briefly described and the target specification derived from the device and the wave tank performance. The design for the brushless permanent-magnet generators is then developed using SPEED PC-BDC and verified using finite element analysis (PC-FEA). A...

This paper describes a new subgridding approach with a view to improving the efficiency of full-wave simulation of electronic circuits. The proposed subgridding method has been incorporated into a full-wave variable-mesh finite-difference transmission line matrix (FD-TLM) simulator. By incorporating the proposed subgridding method, a speed-up of about 2 has been attained. The computational acce...

This paper investigates some fourth-order accurate explicit finite difference schemes for the 2-D wave equation obtained using 13-, 17-, 21-, and 25-point discrete Laplacians. Optimisation is conducted in order to minimise numerical dispersion and computational costs. New schemes are presented that are more computationally efficient than nine-point explicit schemes at maintaining less than one ...

With the rapid growth of indoor wireless communication systems, the need to accurately model radio wave propagation inside the building environments has increased. Many site-specific methods have been proposed for modeling indoor radio channels. Among these methods, the ray tracing algorithm and the finite-difference time domain (FDTD) method are the most popular ones. The ray tracing approach ...

For an abstract self-adjoint operator L and a local operator A we study the boundedness of the Riesz transform AL on L for some α > 0. A very simple proof of the obtained result is based on the finite speed propagation property for the solution of the corresponding wave equation. We also discuss the relation between the Gaussian bounds and the finite speed propagation property. Using the wave e...

The objective is to develop a hybrid one-dimensional finite element (FE)/analytical method to analyze the Lamb Wave propagation characteristics in a composite panel for the purpose of detecting the specific structural defects in the composite panel. Here, it is proposed to use a composite panel using a finite element approximation in the thickness direction while wave solutions are assumed in t...

This paper was aimed to report the 3D finite element analysis simulation of laser welding process of Ti6Al4V 1.7 mm sheets in butt joint in order to predict the temperature distribution, hardness, and weld geometry. The butt-joint welds were made using CO2 laser with the maximum power of 2.2 kW in the continuous wave mode. A part of the experimental work was carried out to verify the weld geome...

The present article investigates the thermoelastic interaction in a three-dimensional homogeneous and isotropic sandwich structure using the dual-phase-lag (DPL) model of generalized thermoelasticity. The incorporated resulting non-dimensional coupled equations are applied to a specific problem in which a sandwich layer of unidentical homogeneous and isotropic substances is subjected to time-de...