Showing 3 results for Ansar
M. Ashuri, F. Moztarzadeh, N. Nezafati, A. Ansari Hamedani, M. R. Tahriri,
Volume 31, Issue 1 (Jun 2012)
Abstract
In the present study, a bioceramic-based composite with remarkable mechanical properties and in vitro apatite forming ability was synthesized by sintering compacts made up of mixtures of hydroxyapatite (HA) and sol-gel derived bioactive glass (64SiO2-26CaO-5MgO-5ZnO) (based on mole %). HA was synthesized through co-precipitation method. The stabilization temperature of the bioactive glass was set to be 700 ºC according to simultaneous thermal analysis (STA). Laser Particle Size Analysis (LPSA) was used to compare the particle size distributions of the synthetic powders. HA matrix was mixed with different weight percentages of bioactive glass (5, 10, 15, 20, 25 and 30 wt. %) and compressed by 80 MPa pressure. After sintering the uniaxial compression test of the samples was done and the specimen with the highest compressive strength (20 wt. % bioactive glass) was selected to be immersed in the Simulated Body Fluid (SBF) for 3, 7 and 14 days. The results showed that the compressive strength of the sample decreased after keeping it in the SBF. Also, inductively coupled plasma analysis (ICP) was used to study the ion release behavior of the sample in the SBF. Finally, phase composition, microstructure and functional groups in the composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infra-red spectroscopy (FTIR) techniques, respectively.
Z. Ansari, M. Alizadeh, A. Sadeghzadeh Attar,
Volume 33, Issue 2 (Journal of Advanced Materials-fall 2015)
Abstract
In this study, mixed metal oxides Al2O3/MgO/TiO2 coatings with Al/Mg/Ti ratios of 5:1:3 and 2.5:3:4 were coated on AA1100 aluminum by sol-gel method. The surface morphology, phase analysis and the corrosion behavior of the Al2O3/MgO/TiO2 coatings were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and electrochemical impedance spectroscopy measurements (EIS) in 3.5 wt.% NaCl solution. The thermal behaviors, the bonds configuration, and functional groups of the coated samples were studied by thermo-gravimetric and differential thermal analysis (TG-DTA) and Fourier transform infrared spectroscopy (FTIR), respectively. The results demonstrated that heat treatment at
450 °C caused an increase in porosity and coating cracking, finally leading to the decrease of corrosion resistance. The best corrosion resistance was achieved for the sample with Al/Mg/Ti molar ratio of 5:1:3 without any heat treatment. The structure of this sample was amorphous, and heat treatment resulted in crystallization and decrease of the corrosion resistance.
M. Sohrabi, M. Abbasi, M. M Ansar,
Volume 38, Issue 1 (Journal of Advanced Materials-Spring 2019)
Abstract
In this study, using biodegradable polymers, nanofiberouse scaffolds were fabricated from the layer-by-layer electrospinning method, including two layer that poly (ε-caprolactone), polyvinylpyrrolidone deposited at first layer and poly (ε-caprolactone), polyvinyl alcohol , β-tricalcium phosphate at latter. After prepration of scaffolds, scanning electron microscopy (SEM), swelling, porosity, mechanical properties and biodegradability behavior in buffered saline phosphate solution were studied. The results confirmed the bioactivity and suitable mechanical properties of the layer-by-layer scaffold. The swelling increase with the addition of hydrophilic polymers and reache 811 ± 214 % in the layer-by-layer scaffold, which reveald a significant difference compared to pure PCL. The MTT test on the layer-by-layer scaffold, after 3, 5 and 7 days of rats bone marrow stem cells (rMSC) culture, showed the cell viability of above 80% moreover, cells morphology on the scafold indicated the optimal compatibility of cells on the scaffold.
