Sharif Digital Repository

In order to study the Hall effect in pure and CNT-doped Y-123 polycrystalline samples, we have measured the longitudinal and transverse voltages at different magnetic field (0 - 9 T) in the normal and vortex states. In the normal state, the Hall coefficient is positive and decreases with increasing temperature, and can be approximately fitted to RH = a + bT-1. We have found a sign reversal in the pure sample for the magnetic field of about 3 T, and double sign reversal of the Hall coefficient in the 0.7 wt% CNT-doped sample at about 3 and 5 T. The Hall resistivity in our samples depends on the pinning  

In the current research, a three-dimensional photovoltaic thermal system integrated with phase change material system with nanofluids is investigated. The working fluids involved in this study include nano-magnesium oxide, multiwall carbon nano tube and hybrid (mixture of nano-magnesium oxide and nano-multiwall carbon nano tube) nanofluids dispersed in pure water. After comparing single-phase model and mixture model, the mixture model is used in the study and fluid flow regime in the collector is assumed to be laminar, fully develop, uniform and incompressible, to model the nanofluid in the system. A parametric analysis is conducted to examine the effect of various parameters such as working... 

The preparation and electrochemical performance of the carbon nanotube-paste electrode modified with salophen complexes of cobalt(III) perchlorate, with various substituents on the salophen ligand, as well as their electrocatalytic activity toward the oxidation of N-acetylcysteine (NAC) is investigated. Several Schiff base complexes containing various nucleophilic and electrophilic functional groups were prepared, and their electrochemical characteristics for the electro-oxidation of NAC were evaluated using cyclic and differential pulse voltammetry (CV and DPV). The results revealed, the modified electrodes show an efficient and selective electrocatalytic activity toward the anodic...