Bis (dibenzylidene acetone) palladium (0) catalyst for glycerol oxidation in half cell and in alkaline direct glycerol fuel cell

In this study, catalytic activity and performance of bis (dibenzylidene acetone) palladium (0) catalyst, Pd (DBA)₂, was evaluated toward glycerol oxidation reaction (GOR) in alkaline half cell and alkaline direct glycerol fuel cell (DGFC). The electrooxidation of glycerol on Pd (DBA)₂ was characterized in half cell by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) techniques. Obtained results have highlighted the excellent electrocatalyst activity of Pd (DBA)₂ in terms of specific peak current density and onset potential compared to the results obtained by conventional Pd base catalysts. CVs results also demonstrate that Pd (DBA)₂ is still active even after 200 cycles.     

Detection of broken rotor bars in induction motors using nonlinear Kalman filters

This paper presents a model-based fault detection approach for induction motors. A new filtering technique using Unscented Kalman Filter (UKF) and Extended Kalman Filter (EKF) is utilized as a state estimation tool for on-line detection of broken bars in induction motors based on rotor parameter value estimation from stator current and voltage processing. The hypothesis on which the detection is based is that the failure events are detected by jumps in the estimated parameter values of the model. Both UKF and EKF are used to estimate the value of rotor resistance. Upon breaking a bar the estimated rotor resistance is increased instantly, thus providing two values of resistance after and before bar breakage. In order to compare the estimation performance of the EKF and UKF, both observers are designed for the same motor model and run with the same covariance matrices under the same conditions. Computer simulations are carried out for a squirrel cage induction motor. The results show the superiority of UKF over EKF in nonlinear system (such as induction motors) as it provides better estimates for rotor fault detection.     

A new model for investigating the flexural vibration of an atomic force microscope cantilever

A new model for the flexural vibration of an atomic force microscope cantilever is proposed, and a closed-form expression is derived. The effects of angle, damping and tip moment of inertia on the resonant frequency were analysed. Because the tip is not exactly located at one end of the cantilever, the cantilever is modelled as two beams. The results show that the frequency first increases with increase in angle and then decreases to a constant value for high values of the angle. Moreover, the damping is increased at lower contact positions. The tip moment of inertia is also sensitive to the resonant frequency at small values for the odd modes and large values for the even modes.     

The optimization of thermal performance of an air cooler equipped with butterfly inserts by the use of imperialist competitive algorithm

The aim of this paper is to apply a novel optimization algorithm based on the imperialist competitive algorithm (ICA) to optimize the thermal performance of an air‐cooled heat exchanger equipped with butterfly inserts. Experiments included inserts inclined at angles ranging from 45 to 135°. Also, the Reynolds number varied from 4021 to 16118. After data reduction, the regression equation of thermal performance was obtained as a function of the Reynolds number and the inclined angle. Then the cost function was optimized by the use of ICA. One can be sure that the thermal performance will be optimized due to the optimization of the cost function. Computational results indicate that the proposed optimization‐algorithm is quite effective and powerful in optimizing the cost function. According to the results, in order to obtain maximum performance, the inclined angle must be about 95°. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.20412     

Green Synthesis of Novel Class of Azo Dyes Based on Naphthols,Coumarins, and Phenols with Molybdate Sulfuric Acid

A new series of polycyclic aromatic azo dyes based on naphthols, coumarins, and phenols were efficiently synthesized by the diazotization of 7-amino coumarins in the presence of catalytic amounts of molybdate sulfuric acid (MSA) followed by coupling reactions. The diazotization and subsequent azo-coupling generated the related azo dyes at 0–5°C in short reaction times with a simple experimental procedure.     

Sizing of rock fragmentation modeling due to bench blasting using adaptive neuro-fuzzy inference system and radial basis function

One of the most important characters of blasting, a basic step of surface mining, is rock fragmentation. It directly effects on the costs of drilling and economics of the subsequent operations of loading, hauling and crushing in mines. Adaptive neuro-fuzzy inference system (ANFIS) and radial basis function (RBF) show potentials for modeling the behavior of complex nonlinear processes such as those involved in fragmentation due to blasting of rocks. In this paper we developed ANFIS and RBF methods for modeling of sizing of rock fragmentation due to bench blasting by estimation of 80% passing size (K₈₀) of Golgohar iron ore mine of Sirjan, Iran. Comparing the results of ANFIS and RBF models shows that although the statistical parameters RBF model is acceptable but the ANFIS proposed model is superior and also simpler because the ANFIS model is constructed using only two input parameters while seven input parameters used for construction of the RBF model.     

Analytical modeling of low velocity impact on carbon nanotube-reinforced composite (CNTRC) plates

In this paper, a new analytical model for behavior of carbon nanotubes reinforced composite plates under low velocity impact has been presented. Nanotubes aligned, straight and randomly oriented are distributed on rectangular simply supported composite plate. The Mori–Tanaka model is used to obtain effective mechanical properties of composites reinforced with nanotubes consisting of aligned, straight and randomly oriented carbon nanotubes embedded in a polymer matrix. The analytical model based on the first-order shear deformation theory and spring-mass model. The results of analytical model are compared with the results of low velocity impact on fiber-reinforced polymer composites. The results show that the deflection and energy absorption of plate in a randomly oriented distribution is more than aligned straight of carbon nanotubes in the composite layers.