An equivalent circuit model for predicting the frequency response of a square ring slot frequency selective surface (SRS-FSS) for normal incidence is described. The proposed FSS consists of an array of square patches centered within a wire grid. The presented circuit model is formed by the impedance of the wire grid that is parallel with the impedance of the patch array, also the mutual couplin...

A modified circular patch antenna design has been proposed in this paper, the bandwidth of this antenna is optimized using the genetic algorithm (GA) based on fuzzy decision-making. This design is simulated with HP HFSS Program that based on finite element method. This method is employed for analysis at the frequency band of 1.4 GHz- 2.6 GHz. It gives good impedance bandwidth of the order o...

This paper is concerned with investigation of vertical impedance function of a surface rigid circular foundation resting on a semi-infinite transversely isotropic alluvium. To this end, the equations of motion in cylindrical coordinate system, which because of axissymmetry are two coupled equations, are converted into one partial differential equation using a method of potential function. The g...

In the present work the effects of plasma nitridization on the passivation behavior of AISI 316L was investigated. To do this; nitriding treatments were carried out at 420°C for 1, 2, 4 and 16 hours. The phase composition and structure of the nitrided layer were studied by Low Angle X-ray diffraction and Scanning Electron Microscopy. The hardness of samples also was evaluated by Vickers microha...

In this study, the Al/Al2O3-SiC hybrid composite was produced by accumulative roll bonding (ARB). In the first and the second cycles, the particles were uniformly poured between the Al strips during each ARB cycle. In the subsequent cycles, ARB was repeated up to six cycles without adding the particles between the layers. After the total eight cycles, the particles were distributed uniformly wi...

The transient response of passivated metallic electrode system under potential step was analyzed based on a linear model, and a technique for calculating the parameters characterizing the growth and dissolution of passive film was proposed. It is believed that the information which is expected to be gained from the impedance measurement can be obtained by this technique and that this technique ...

Researchers and practitioners have long utilized a variety of penetrometers to investigate the snowpack. Identifying definitive relationships between penetrometer-derived microstructural information and stability has been challenging. The purpose of this study is two-fold: 1. We propose a simple field test that can be implemented by the scientific community to establish relationships between lo...

Electrochemical impedance spectroscopy and gravimetric methods were carried out to analyze water uptake of thin polyurethane films separately filled with either hydrophobic or hydrophilic nano-silica. Correspondingly the impedance spectra and gravimetric data were interpreted in terms of movement of water within the coating and/or to the coating/metal interface. Although the obtained results fr...

In this paper, the effect of surface area of reaction layers in gas diffusion electrodes on oxygen reduction reaction was investigated. For this purpose, various amounts (0.1, 0.2, 0.3, 0.4, 0.5, 1, 1.5 and zero %wt of total loading of reaction layer) of single walled carbon nanotube (SWCNT) were inserted in the reaction layer. The performance of gas diffusion electrodes for oxygen reduction re...