Showing 7 results for Shirani
E. Shirani,
Volume 5, Issue 1 (10-1987)
Abstract
E. Shirani, M.r. Khosrawi- Rad,
Volume 7, Issue 1 (7-1989)
Abstract
E. Shirani, A. Esmaeeli,
Volume 11, Issue 1 (10-1992)
Abstract
E. Shirani, and H. Ahmadikia,
Volume 19, Issue 2 (1-2001)
Abstract
2-D and axisymmetric Navier-Stokes equations are solved using Reiman-Roe solver with different limiters for second-order accurate schemes. The results were obtained for supersonic viscous flows over semi-infinite axisymmetric and 2-D bodies. The free stream Mach numbers were 7.78 and 16.34. The stability of Roe method with different limiters and entropy conditions were considered. The results show that the limiters greatly affect the stability and accuracy of the numerical solution while the entropy conditions do not.
M. Talebi, E. Shirani, and M. Ashrafizadeh,
Volume 25, Issue 2 (1-2007)
Abstract
In this study, turbulent flow around a tube bundle in non-orthogonal grid is simulated using the Large Eddy Simulation (LES) technique and parallelization of fully coupled Navier – Stokes (NS) equations. To model the small eddies, the Smagorinsky and a mixed model was used. This model represents the effect of dissipation and the grid-scale and subgrid-scale interactions. The fully coupled NS equations with the multiblock method was parallelized. Parallelization of the computer code was accomplished by splitting the calculation domain into several subdomains and using different processors in such a way that the computational work was equally distributed among processors. The discretized governing equations are second order in time and in space and the pressure is calculated by Momentum Interpolation Method (MIM) to prevent the checkerboard problem. The results are obtained for the turbulent flow over five parallel tube rows. The computational efficiency, flow patterns, and flow properties are also determined. The results showed high parallelization efficiency and high speed up for the computer code. The flow characteristics were determined and compared with experimental results which showed good agreement. Also, the results showed that the mixed model is better than the Smagorinsky model for evaluation of flow characteristics and lift and drag forces on tubes.
F.s. Sayyedan, M.h. Fathi, H. Edris, A. Doostmohamadi, V.s., Mortazavi, F. Shirani,
Volume 33, Issue 3 (Journal of Advanced Materials- winter 2015)
Abstract
The objective of this study was to synthesize glass ionomer–forsterite nanocomposite and study the effect of
incorporating forsterite nanoparticles to the ceramic part of glass ionomer cement in order to improve mechanical properties and
bioactivity. So, Forsterite nanoparticles were made by the sol-gel process using different weight percentages added to the ceramic
part of commercial GIC (Fuji II GC). X-ray diffraction (XRD) was used in order to characterize and determine grain size of the
produced forsterite nanopowder. In order to study the mechanical properties of the produced glass ionomer cement-forsterite
nanocomposite, the compressive strength (CS), three-point flexural strength (FS) and diametral tensile strength (DTS) of
specimens were measured. Statistical analysis was done by one Way ANOVA and differences were considered significant if
P‹0.05. The morphology of fracture surface of specimens was studied using scanning electron microscopy (SEM) technique.
Bioactivity of specimens was investigated by Fourier transitioned-infrared spectroscopy (FTIR), scanning electron microscopy
(SEM), and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The results of XRD analysis confirmed the
nanocrystalline and pure forsterite synthesis. According to the mechanical properties measurements, the optimum weight
percentages of forsterite nanoparticles for enhancement of CS, FS, and DTS were obtained equal to 3, 1 and 1 wt.%, respectively.
Statistical analysis showed that the differences between all the groups were significant (P<0.05). SEM images and results of the
ICP-OES and FTIR tests confirmed the bioactivity of the nanocomposite. Glass ionomer-forsterite nanocomposite containing 1 to
3 wt.%-forsterite nanoparticles can be a suitable candidate for dentistry and orthopedic applications due to the improvement of
mechanical properties and bioactivity.
E. Shirani, A. Razmjou,
Volume 36, Issue 4 (Journal of Advanced Materials-Winter 2018)
Abstract
The significance of producing superhydrophobic surfaces through modification of surface chemistry and structure is in preventing or delaying biofilm formation. This is done to improve biocompatibility and chemical and biological properties of the surface by creating micro-nano multilevel rough structure; and to decrease surface free energy by Fault Tolerant Control Strategy (FTCS) . Here, we produced a superhydrophobic surface through TiO2 coating and flurosilanization methods. Then, in order to evaluate the physicochemical properties of the modified surfaces, they were characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Contact Angle (CA), cell viability assay (using Hela and MCF-7 cancer cell lines as well as non-cancerous human fibroblast cells) by MTT, Bovine Serum Abumin (BSA) protein adsorption using Bradford and bacterial adhesion assay (Staphylococcus aureus and Staphylococcus epidermidis) using microtiter. Results showed that contact angle and surface energey of superhydrophobic modified surface increased to 150° and decreased to 5.51 mj/m2, respectively due to physicochemical modifications of the surface. In addition, the results showed a substantial reduction in protein adsorption and bacterial cell adhesion in superhydrophobic surface.
