A glassy carbon immunoelectrode modified with vanadium oxide nanobelts for ultrasensitive voltammetric determination of the core antigen of hepatitis C virus

Microchimica Acta - The authors describe a voltammetric immunoassay for the hepatitis C virus core antigen. It is based on the use of vanadium oxide nanobelts that were used to modify a glassy...     

An iterative approach to solve multiobjective linear fractional programming problems

This paper suggests an iterative parametric approach for solving multiobjective linear fractional programming (MOLFP) problems which only uses linear programming to obtain efficient solutions and always converges to an efficient solution. A numerical example shows that this approach performs better than some existing algorithms. Randomly generated MOLFP problems are also solved to demonstrate the performance of new introduced algorithm.     

Heat transfer intensification in microchannel by induced-charge electrokinetic phenomenon: a numerical study

Journal of Thermal Analysis and Calorimetry - In this numerical investigation, the induced-charge electrokinetic phenomenon is used to intensify the convective heat transfer rate in the...     

Efficient Oxidation of Hantzsch 1,4-Dihydropyridines with Tetrabutylammonium Peroxomonosulfate Catalyzed by Manganese(III) Schiff Base Complexes: The Effect of Schiff Base Complex on the Product Selectivity

Efficient and rapid oxidation of Hantzsch 1,4-dihydropyridine with tetrabutylammonium peroxomonosulfate (TBAO) is reported. The Mn(salophen)/monopersulfate catalytic system efficiently converts 1,4-dihydropyridines (DHPs) to their corresponding pyridine derivatives under mechanical stirring and microwave irradiation in CH₂Cl₂. The ability of various Schiff base complexes to oxidize DHPs was also investigated. The results showed that in the presence of manganese Schiff complex, no by-product was obtained.     

Rapid and efficient aromatization of Hantzsch 1,4-dihydropyridines with Potassium peroxomonosulfate catalyzed by manganese(III) Schiff base complexes

Rapid and efficient oxidation of Hantzsch 1,4-dihydropyridine with Potassium peroxomonosulfate is reported. The Mn(III)-salophen/monopersulfate catalytic system converts 1,4-dihydropyridines to their corresponding pyridine derivatives at room temperature in a 1:1, CH₃CN/H₂O mixture. The ability of various Schiff base complexes in the oxidation of 1,4-dihydropyridine was also investigated.     

Ultrasonic Measurements of Residual Stresses Caused by Severe Thermomechanical Deformation during FSW

In engineering processes, residual stresses can be intense once high plastic deformation and temperature gradient are involved. This is exactly the case for friction stir welding (FSW) in which both rotational and translational movements of the tool induce extreme temperature gradient and plastic deformation. In this research, the extents of longitudinal and transverse residual stresses are measured within the AA7075-T6 plates welded through FSW process using ultrasonic method. According to the obtained results, it can be found that the residual stress is of the tensile type adjacent to the welding line whereas it is of the compressive type far from the welding line. Another observation is that the longitudinal residual stresses are considerably greater than the transverse residual stresses. Furthermore, with the aim of investigating the effects of rotation and traverse velocities of the tool on residual stress, experiments are carried out at three different rotation and traverse velocities. Based on the acquired results, it is observed that upon increasing the rotation and traverse velocities, the longitudinal and transverse residual stresses decrease and increase, respectively.     

Perturbation Analysis of the Local Thermal Non-equilibrium Condition in a Fluid-Saturated Porous Medium Bounded by an Iso-thermal Channel

This study focuses analytically on the local thermal non-equilibrium (LTNE) effects in the developed region of forced convection in a saturated porous medium bounded by isothermal parallel-plates. The flow in the channel is described by the Brinkman–Forchheimer-extended Darcy equation and the LTNE effects are accounted by utilizing the two-equation model. Profiles describing the velocity field obtained by perturbation techniques are used to find the temperature distributions by the successive approximation method. A fundamental relation for the temperature difference between the fluid and solid phases (the LTNE intensity) is established based on a perturbation analysis. It is found that the LTNE intensity ( $\Delta \textit{NE}$ ) is proportional to the product of the normalized velocity and the dimensionless temperature at LTE condition. Also, it depends on the conductivity ratio, Da number, and the porosity of the medium. The intensity of LTNE condition ( $\Delta \textit{NE}$ ) is maximum at the middle of the channel and decreases smoothly to zero by moving to the wall. Finally, the established relation for the intensity of LTNE condition is simple and fundamental for estimating the importance of LTNE condition and validation of numerical simulation results.     

Numerical Simulation of Forced Convective Heat Transfer Past a Square Diamond-Shaped Porous Cylinder

Fluid flow and heat transfer around and through a porous cylinder is an important issue in engineering applications. In this paper a numerical study is carried out for simulating the fluid flow and forced convection heat transfer around and through a square diamond-shaped porous cylinder. The flow is two-dimensional, steady, and laminar. Conservation laws of mass, momentum, and heat transport equations are applied in the clear region and Darcy–Brinkman–Forchheimer model for simulating the flow in the porous medium has been used. Equations with the relevant boundary conditions are numerically solved using a finite volume approach. In this study, Reynolds and Darcy numbers are varied within the ranges of $1<Re<45$ and $10^{-6}<Da<10^{- 2}$ , respectively. The porosity $(\varepsilon )$ is 0.5. This paper presents the effect of Reynolds and Darcy numbers on the flow structure and heat transfer characteristics. Finally, these parameters are compared among solid and porous cylinder. It was found that the drag coefficient decreases and flow separation from the cylinder is delayed with increasing Darcy number. Also the size of the thermal plume decreases by decreasing Darcy number.