فهرست مطالب mehdi arjomand

In the present work, BaCe0.85Yb0.15O3-δ mixed metal oxide nanoparticles supplying strong acid sites and good hydrophilic nature were used for the first time to build organic-inorganic proton exchange membranes. Poly(vinyl alcohol) - BaCe0.85Yb0.15O3-δ (PVAYb) nanocomposite membranes were fabricated. Different analyses such as Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) spectroscopy, Fourier Transform Infra-Red (FT-IR) spectroscopy, and ThermoGravimetry Analysis (TGA) were used to characterize and study the structural properties of the obtained membranes. SEM and EDX analyses exhibited a homogenous dispersion of the nanoparticles in the nanocomposite membrane.  It was found that PVAYb1.5 had a better elemental distribution compared to PVAYb2.5 composite membrane. PVAYb nanocomposite membrane containing 1.5 wt.% of BaCe0.85Yb0.15O3-δ nanoparticles displayed a high proton conductivity value (64 mS/cm) at 70 °C operation temperature. The peak power density of 29 mW/cm2 was obtained with a peak current density of 210 mA / cm2 for as-prepared Proton Exchange Membrane Fuel Cell (PEMFC) equipped with PPYb1.5 nanocomposite membrane at 70 °C.

The purpose of this paper is to find the optimal geometry of Venturi for the production of biodiesel by hydrodynamic cavitation. Intensive methods such as hydrodynamic cavitation eliminate the limitation of mass transfer in the transesterification reaction. In this paper, a venturi design was developed to create cavitation in biodiesel production. The most important property of venturi in creating cavitation and retrieving the pressure is the convergence and divergence angles. The four convergence angles of 22°, 20°, 17°, and 15° and four divergence angles of 12°, 10°, 7° and 5° in Gambit 2.4 software were designed and evaluated with Fluent 6.3 software and their CFD was analyzed. The maximum pressure recovery (85% of input pressure) and cavitation generation was for venturi 17-10 (Convergence angle 17° and divergence angle 10°), which was used in the experimental setup of biodiesel production. The biodiesel production efficiency with this venturi was 95.6%. The FTIR spectrum of the biodiesel was taken to confirm its purity.