An Atomistic Study of the Interacting Crack and Coated Inhomogeneity

, M.Sc. Thesis Sharif University of Technology Ghassemi, Mohsen (Author) ; Mohammadi Shoja, Hossein (Supervisor)

Abstract

Classical continuum mechanics fails to give an accurate solution near the crack tip, moreover, it implies that a solid is able to sustain an infinite stress at the Griffith-Inglis crack tips. Among other critical issues is the inability of classical approach to sense the size effect. For these reasons, for more in-depth understanding and accurate behavioral predictions, it is essential to develop some atomistic methods which properly accounts, not only for the structure but also the long and short range atomic interactions effectively. In this work the interaction of coated inhomogeneity and crack under polynomial loading is simulated by using the many body Rafii-Tabar and Sutton potential...

Study Quantum Phases of Superconducting Kondo Lattice Model In s and p wave symmetry of Gap Function

, M.Sc. Thesis Sharif University of Technology Moghtader, Mohammad Reza (Author) ; Kargarian, Mehdi (Supervisor)

Abstract

In this thesis, first we study superconductivity and its mechanisms then classify different types of that based on symmetry of gap function. After that, we shall discuss metallic systems that have impurities in them and propose two successful model describing this phenomenon, Anderson’s model and Kondo’s model. In the next step, by introducing Kondo lattice model which is an ordered array of impurities in system, try to solve it by mean-field approximation and will be seen a phase transition in a characteristic temperature known as Kondo’s temperature. Then generalize these models to situation when background system is a superconductor and study it’s behavior and quantum phases. Although...

Leaching of Titanium-bearing Concentrate of Solid-state Reduction of Titanomagnetite Ores

, M.Sc. Thesis Sharif University of Technology Babanejad, Safoura (Author) ; Askari, Masoud (Supervisor)

Abstract

Some of the low-grade titanium resources which are located in the country are titanomagnetite placer deposits. In current study, beneficiation of titanium-bearing concentrate of a placer deposit containing 6.13wt.% TiO2 was investigated by acidic leaching in order to remove impurities. To beneficiate the concentrate, based on the optimum conditions obtained in previous studies, solid-state reduction, magnetic separation, and calcination of non-magnetic product were performed. Afterwards, by studying temperature, time, acid concentration and L:S ratio, the final product was leached under optimal conditions were as follows: H2SO4 concentration of 15wt.%, L:S ratio of 20:1 (mL:g), reaction...