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In the present study, a hollow MgO/SiO2 nanocatalyst with high alkaline properties was prepared. This heterogeneous catalyst was prepared in several steps to create a great active area and decrease the density of the catalyst. The alkaline hollow catalyst framework was applied for the reaction of cyclohexanone, malononitrile and benzaldehyde for synthesis of 1 H-isocromene therough the Michael addition and aldol condensation reaction at room temperature. In this method, all of the done reactions were excellent in the yields of products and reaction times. At the end of the reaction, the nanocatalyst separated by simple filtration and reuse in several runs elsewhere. In the present study, hollow MgO/SiO2 nanocatalyst with great base properties was made. Thisheterogeneous catalyst was a synthesis in several steps to create a great active area and decreasethe density of the catalyst [ABSTRACT FROM AUTHOR]

Inspired by the effects of a switching surface on the stability of passive dynamic walking (Safa and Naraghi in Robotica 33(01):195-207, 2015; Safa et al. in Nonlinear Dyn. 81(4):2127-2140, 2015), this paper suggests a new control strategy for stabilization of dynamic bipedal locomotion. It verifies that the stability improvement of a dynamic walking system is feasible while preserving the speed, step-length, period, natural dynamics, and the energy effectiveness of the gait. The proposed control policy goes behind the three primary principles: (i) The system’s switching surface has to be replaced by a new one if an external disturbance is induced. (ii) The new switching surface has to be reshaped back into its old style, together with the disturbance rejection. (iii) The stabilization procedure has to be performed with as small energy consumption as possible. Because of the reversibility effects of the switching surfaces in the above rules, the terminology of “Reversible Switching Surfaces” (RSS) is employed to address the control scheme; so the control objective would be the implementation of RSS for a bipedal robotic system. In this paper, this aim is achieved by a kinematically controlled foot scheme that is implemented on a simple structured biped. The presented idea is validated by a commercial version of MSC Adams software. [ABSTRACT FROM AUTHOR]

The oxidation of acetaminophen was studied at a glassy carbon electrode modified with multi-walled carbon nanotubes and a graphite paste. Cyclic voltammety, differential pulse voltammetry and square wave voltammetry at various pH values, scan rates, and the effect of the ratio of nanotubes to graphite were investigated in order to optimize the parameters for the determination of acetaminophen. Square wave voltammetry is the most appropriate technique in giving a characteristic peak at 0.52 V at pH 5. The porous nanostructure of the electrode improves the surface area which results in an increase in the peak current. The voltammetric response is linear in the range between 75 and 2000 ng.mL, with standard deviations between 0.25 and 7.8%, and a limit of detection of 25 ng.mL. The method has been successfully applied to the analysis of acetaminophen in tablets and biological fluids. [ABSTRACT FROM AUTHOR]