Sharif Digital Repository

This work examines the problem of the fully coupled magneto-electro-elastic (MEE) scattering of SH-waves incident upon a heterogeneous MEE scatterer which is embedded in an unbounded medium. The scatterer consists of a circular core and a circular encapsulator with eccentricity. All three regions: the core, encapsulator, and the surrounding matrix have distinct MEE properties and fully coupled constitutive relations. The generated coupled MEE fields coexist simultaneously in all these regions without resort to any simplifying assumptions. The precise description of the multifunctionality involves the solution of three fully coupled partial differential equations in three different regions.... 

In the present study, the simulation of incompressible Electro-Magneto-hydrodynamic flows is performed using a finite volume lattice Boltzmann method (FVLBM). The Boltzmann transport equation is solved using a cell-centered finite volume method on structured meshes. A central difference scheme is used to discretize the spatial derivatives and the fourth-order numerical dissipation term is added to stabilize the solution. To discretize the temporal derivative, the fourth-order Runge-Kutta time stepping scheme is applied. The standard collision-streaming lattice Boltzmann method has been used to simulate EMHD flows in the literature, however, it has several deficiencies such as the... 

Non-deterministic finite automata (NFA) are an elementary type of Turing machines with very high processing power. NFA processors provide parallelism at the data and task level because they can be in several different output states in one clock cycle. Implementing such machines with memory is a good strategy because if we consider each of the memory columns as a state, by selecting a row of the memory, we can activate several states at the same time, which is an implementation of NFA. NFA-based automata processors were first introduced by Micron and were very powerful for issues such as pattern matching, DNA sequencing, or regular expressions and, in general, for machine learning topics.... 

In the current work, the two- and three-dimensional electro-elastic fields of periodically as well as arbitrarily distributed interacting quantum wires (QWRs) and interacting quantum dots (QDs) of arbitrary shapes within a piezoelectric matrix are studied analytically. The lattice mismatch between the QWR/QD and the barrier is accounted through prescribing an initial misfit strain field within the QWR/QD. The distinction between the electro-mechanical properties of the QWR/QD and those of the barrier is treated by introducing a novel electro-mechanical equivalent inclusion method in Fourier space (FEMEIM). Moreover, the theory can readily treat cases where the QWRs/QDs are multi-phase or... 

Micropumps are regarded as one of the devices used in microsystems, which are responsible for pumping working fluid. The Mercury Magneto Reciprocating (MMR) micropump, which has been introduced for less than a decade, is an innovative kind of micropumps which the pumping agent includes three liquid metal droplets (LMD) placed inside lateral chambers and reciprocated by the electromagnetic force inside the chambers. The working fluid located inside the main channel is pumped through due to the movement of these three LMDs. The equations governing this micropump are complex and their numerical solution is a time-consuming process, due to electromagnetic, hydrodynamic, and unsteady effects. The... 

Magnetic shape memory alloys (MSMAs) are a new class of smart materials which exhibit properties such as large reversible strains and high performance frequencies. These unique properties, offer magnetic shape memory alloys as an option in applications such as actuators, sensors and energy harvesters. In this thesis, the equations of magnetic shape memory alloys by considering nonlinear terms of Von karaman in strain-displacement relations, is expanded by using the theory of thin plates in two dimensions which can be used for plate equations with any boundary conditions by applying elastic boundary. In order to verify the obtained model, the equations of motions of magnetic shape memory... 

Magnetic shape memory alloys (MSMAs) are a new class of smart materials that exhibit characteristics of large recoverable strains and high frequency. These unique characteristics, make MSMAs interesting materials for applications such as actuators, sensors, and energy harvesters. This thesis presents a three-dimensional phenomenological constitutive model for MSMAs, developed within the framework of irreversible continuum thermodynamics. To this end, a proper set of internal variables is introduced to reflect the microstructural consequences on the material macroscopic behavior. Moreover, a stress-dependent thermodynamic force threshold needed for variant reorientation is introduced which... 

In this thesis, light transmission in dielectric slit arrays on metallic and magneto-optical material has been analyzed by mode matching method together with numerical simulations on commercial softwares such as Comsol Multiphysics and CST microwave studio. It has been shown that light transmission can be attributed to either the Fabry-Perot resonances or a collective resonance phenomenon across the array. In the first case, the transmission resonance is related to the slit depth and is confined to a single slit. In the second case; however, the resonant mechanism affects several neighboring slits. Surprisingly the former is converted to the latter by increasing the slit depth. Furthermore... 

In this thesis we study the possibility of unidirectional transmission of light using reciprocal and nonreciprocal elements. Unidirectional transmission will allow us to separate the coupling of light into and out of resonators and design unidirectional waveguides. We start by studying the effects of one-sided modulations of dielectric constant of reciprocal structures. One-sided modulation will satisfy the phase matching condition for the coupling of two waves only in one direction. Using coupled mode theory, we study one sided modulation in layered media. Next, we find the exact solution to such strucures using transfer matrix method and analyze one-sided modulation in waveguide...