Amirkabir University of Technology

About: Amirkabir University of Technology is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Nonlinear system & Finite element method. The organization has 15254 authors who have published 31165 publications receiving 487551 citations. The organization is also known as: Tehran Polytechnic & Tehran Polytechnic University.

Vibration analysis of functionally graded graphene platelet reinforced cylindrical shells with different porosity distributions

Abstract: This paper studies free vibrational behavior of porous nanocomposite shells reinforced with graphene platelets (GPLs). GPLs are uniformly and nonuniformly distributed thorough the thickness directi...

Simple chaotic 3D flows with surfaces of equilibria

Abstract: Using a systematic computer search, twelve simple three-dimensional chaotic flows were found that have surfaces of equilibria. Although there are some four-dimensional systems with surfaces of equilibria, there is no such system in three-dimensional state space reported in the literature. Such systems are not difficult to design, but they can have some practical benefits. Study of chaotic flows with surfaces of equilibria provides a good reference for building systems with attractors that are protected from external influences, which can increase the safety of engineering.

The role of brookite in mechanical activation of anatase-to-rutile transformation of nanocrystalline TiO2: An XRD and Raman spectroscopy investigation

Abstract: The mechanism of phase transformation in nanocrystalline TiO2 powders at ambient temperature during high energy ball milling and the role of brookite phase in anatase-to-rutile phase transformation were investigated by the use of Rietveld analysis of X-ray diffraction patterns and Raman spectroscopy methods. The milling process was performed on a fully anatase phase nanocrystalline TiO2 powder via a high energy planetary ball mill with different ball-to-powder weight ratios followed by annealing of the as-milled samples. Some transformation from anatase-to-brookite was observed in all as-milled powders by high resolution transmission electron microscopy. It was proposed that brookite occurs at the {112} twin surfaces of anatase phase and therefore promotes anatase-to-rutile phase transformation. Based on the XRD and Raman results, it was proposed that brookite appears as an essential intermediate phase in mechanically induced anatase-to-rutile phase transformation which facilitates the phase transformation at ambient temperatures and also at higher temperatures during the post-annealing step.