The purpose of this paper is to study the characteristics of the combined convection heat transfer and a micropolar nanofluid flow passing through an impermeable stretching sheet in a porous medium.The nanofluid flow field is affected by a magnetic field perpendicular to the sheet.The dynamic viscosity of the micropolar nanofluid changes under the influence of the magnetic field.The continuity,linear momentum,angular momentum,and energy equations are first simplified using the order of magnitude technique that,along with the applied boundary conditions and the definition of the appropriate parameters,are transferred to the similarity space using the similarity analysis.Then the resulting equations are solved using the Runge–Kutta method.The distinction of the macroscale and microscale flow fields and temperature fields resulting from different nanoparticle shapes was clarified.Increasing the Hartmann number,the vortex viscosity parameter,the magnetic parameter,the nanoparticle volume fraction,and the permeability parameter of the porous media increased the surface friction on the sheet.Increasing the vortex viscosity parameter,the magnetic parameter,and the volume fraction of the nanoparticles increases the Nusselt number.
Ce_(2)(MoO_(4))_(3)was synthesized by a simple reflux method using cerium nitrate hexahydrate and ammonium molybdate as reactants.The as-prepared Ce_(2)(MoO_(4))_(3)was characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),Scanning electron microscope(SEM),and X-ray photoelectron spectroscopy(XPS).The removal of dibenzothiophene(DBT)in model oil was studied using Ce_(2)(MoO_(4))_(3)as catalyst and oxygen as oxidant.The reaction factors such as reaction temperature,amount of catalyst,and sulfide type on sulfur removal were researched.The results prove that both Ce3+and MoO42-play significant role in the conversion from DBT to DBTO2.The Ce_(2)(MoO_(4))_(3)catalyst has an excellent performance for the sulfur removal of DBT.Under the optimum reaction conditions,sulfur removal of 99.6%was obtained.After recycling five times,no significant loss in catalyst activity of Ce_(2)(MoO_(4))_(3).Mechanism of aerobic oxidative desulfurization was proposed based on the experiment of free radical capture and infrared characterization.
