In this study, the modeling of hydrogen production process in microreactors by methanol-steam reforming reaction is investigated. The catalytic reaction of methanol-steam reforming producing hydrogen is simulated considering a 3D geometry for the microreactor. To calculate diffusion among species, mixture average correlations are compared to Stephan-Maxwell equations. The reactions occurring in...

In this work, two electromagnetic models are used for the characterization of a planar structure including a flat, thick copper conductor. Indeed the first model is consisted by modeling two metal ribbons without bulkiness, placed one above the other at a distance of h2 equal to the thickness of the thick conductor. This approach has been implemented and tested by the iterative method. The resu...

In microstrip patch antenna array, the mutual coupling is very critical due to surface wave excitation. It leads to degradation in radiation pattern and reduction in gain. In this paper, a method to mitigate mutual coupling effect in an antenna array using Slotted Ground Structure (SGS) at 900MHz and dielectric constant 2.2 is simulated and analyzed using Ansoft HFSS 13. Simulated results show ...

BUILDING A NEW MODEL It is possible to incorporate the temperature and bias dependency of power HBTs in a model by using a thermal network to represent the self-heating and thermal coupling. Such an improved multi-finger HBT model was developed and implemented in a nonlinear circuit simulator, Serenade, from Ansoft Corp. When increasing the collector-emitter voltage of a unit finger HBT, an inc...

This paper investigate some methods for converting single band antennas to multiband antennas so that all single band antennas convert in multiband antennas and gives multiband facility without increasing the cost of manufacturing. Simulation is performing on Ansoft HFSS and corresponding result are shown by figures. Impedance bandwidth, VSWR and Return loss are observed for the proposed antenn...

Linear stability of double diffusive convection of Darcy-Maxwell fluid with Soret and Dufour effects is investigated. The effects of the Soret and Dufour numbers, Lewis number, relaxation time and solutal Darcy Rayleigh number on the stationary and oscillatory convection are presented graphically. The Dufour number enhances the stability of Darcy-Maxwell fluid for stationary convection while it...

This paper deals with theoretical investigation on a compact frequency selective surface with multiple resonant frequencies. In this paper the FSS is designed by modifying square patch nearly similar as ‘H’ shaped patch and then cutting hexagon shaped slot within it. 94.93% size reduction is achieved in this design. Three resonant frequencies have been obtained in this design. Theoretical inves...

A modified printed Yagi antenna with a simplified feed mechanism is proposed. In the new design, the driver dipole is fed by a transmission line formed by two parallel strips printed on opposite sides of the dielectric substrate. This simplified feed structure results in the reduction of the transmission line length, and, consequently, the radiation losses. The analysis of the modified Yagi ant...

As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz .In this paper we introduce a new multilayer microstrip antenna for ultra wideband applications. In order to achieve suitable bandwidth, the antenna size is fine for mobile application...