Showing 4 results for mansouri
S. H. Mansouri, S. M. Hosseini Sarvari, A. Keshavarz and M. Rahnama,
Volume 16, Issue 1 (7-1997)
Abstract
In this paper, a Schwarz-Christoffel method for generating two-dimensional grids for a variety of complex internal and external flow configurations based on the numerical integration procedure of the Schwarz-Christoffel transformation has been developed by using Mathematica, which is a general purpose symbolic-numerical-graphical mathematics software. This method is highly accurate (fifth order) with mesh size, and is highly flexible for treatment of complex internal flow geometries, for a high degree of control of mesh spacing, and for generation of either orthogonal or non-orthogonal grids. In addition, this method directly generates two-dimensional incompressible potential flow solutions for internal flow, and simply or symmetrical multiply connected external flows: it generates a C type grid for a general multiply connected two-dimensional external flow. The capabilities of this method has been shown by sample cases including external flow over symmetric and antisymmetric airfoils, a car profile, and internal flows with arbitrary shapes. To facilitate further applications, a computer program using Mathematica software has been developed.
F. Mansouri, M. Mehran,
Volume 39, Issue 1 (Journal of Advanced Materials-Spring 2020)
Abstract
In this paper, synthesis of inverted nano-pyramids on a single crystal silicon surface through a simple and cost-effective wet chemical method is surveyed. These structures were synthesized by MACE process using Cu as the assisted metal in the solution of copper nitrate, hydrogen peroxide and hydrofluoric acid for different etching times. FE-SEM images of the samples show that time is an important factor in the formation of silicon inverted nano-pyramids and by extending synthesis time the structures gradually fade. After synthesis, some samples were etched in KOH 2% and IPA 6% for one minute which resulted in formation of nano-pyramids besides inverted nano-pyramids on the silicon surface. Formation of these combinational structures affected the self-cleaning behavior of the silicon surface. X-ray diffraction (XRD) was utilized for studying the crystalline characteristics of the synthesized structures. Moreover, the self-cleaning behavior of them was studied using the contact angle goniometer. The results showed that the inverted nano-pyramids improve the hydrophilic behavior of the silicon surface while post-synthesized etching improves the hydrophobic behavior of the surface. These textures improve the performance of solar cells due to their self-cleaning and light adsorption properties
H. R. Karimi, H. Mansouri, M. R. Loghman Estarki, M. Tavoosi , H. Jamali,
Volume 40, Issue 1 (Journal of Advanced Materials-Spring 2021)
Abstract
This study aimed to compare the phase changes and morphology of yttria-stabilized zirconium oxide powders (YSZ) synthesized by co-precipitation and molten salt methods. Ammonia precipitating agent was used for the synthesis of YSZ powder by co-precipitation method and a mixture of sodium carbonate and potassium carbonate salts was used as a molten salt in the molten salt method. Samples were characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC) analysis. The results showed that only the sample prepared with zirconium oxychloride and yttrium nitrate by co-precipitation method had a single phase of yttria-stabilized zirconium oxide with tetragonal crystal lattice and particle size distribution in the range of 30 to 55 nm. The powder synthesized by the molten salt method contained a mixture of zirconia with monoclinic crystal lattice and yttria stabilized zirconia with tetragonal crystal lattice and particle size of 200 nm.
M. Khosravi , M. Mansouri, A. Gholami, Y. Yaghoubinezhad,
Volume 40, Issue 1 (Journal of Advanced Materials-Spring 2021)
Abstract
In this research, the effect of graphene oxide (GO) and reduced graphene oxide (RGO) nanosheets on the mechanical and microstructural properties of AISI 304 stainless steel welded joints produced by the flux-cored arc welding (FCAW) method was investigated. Light microscope, field emission scanning electron microscope (FE-SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction analysis (XRD), Raman spectroscopy, and tensile strength test were used to characterize the samples. GO was synthesized by modified Hummers’ method and reduced by hydrazine. Accordingly, the pastes of GO and RGO in different concentrations of 1, 3, and 10 mg/ml were applied in the groove. The results demonstrated that increasing the RGO concentration up to 10 mg/ml improves the tensile strength and hardness values of welded joints up to 23% and 43%, respectively. It seems that RGO nanosheets have a significant effect on the mechanical properties of the welded joints by pinning of dislocations.
