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.... 

With the progress of engineering science, the development of underground spaces and buried tunnels has witnessed remarkable expansion. Considering the frequency of hazardous events such as earthquakes and unforeseen consequences arising from underground activities and geology in underground engineering, the determination of the Dynamic Stress Concentration Factor (DSCF) has been widely recognized as a crucial factor in the study and design of tunnels and underground structures. It is also extensively considered in evaluating their damage. The investigation of wave dispersion and determination of the stress concentration factor was first proposed by Sezawa (1927). In this study, the... 

The purpose of this work is to introduce an inverse finite element tool for prediction of the blank geometry and forming severity in stamping of 3D sheet metal parts. To achieve this goal total deformation theory of plasticity has been employed. In this method the final 3D part is unfolded on the flat surface in one step and on predefined surface in multistage analysis. The problem for one step analysis is reduced to two dimensional computations. The effect of curvature of initial blank and the number of stages in forming process are also considered. To investigate the capability of this work, predictions of the blank shape and strain distribution and forming severity have been performed on... 

The  usual  continuum  theories  are  inadequate  in  predicting  the  mechanical  behavior of solids in presence of small defects and stress concentrators; it is well known that such continuum methods are unable to detect the change of the size of  the  inhomogeneities  and  defects.   For  these  reasons  various  augmented  continuum theories and strain gradient theories have been proposed in the literature. The major difficulty in implication of these theories lies in the lack of information  about  the  additional  material  constants.  For  fcc  metals,  for  calculation of the associated characteristic lengths which arise in first strain gradient  theory,  an ... 

Salicylaldehyde-amino acid Schiff base complexes are used as non-enzymatic models for the metal-pyridoxal (Vitamin B6) amino acid Schiff base systems which are key intermediates in many metabolic reactions of amino acids catalyzed by enzymes which require pyridoxal as a cofactor (transamination, decarboxylation, α and β elimination, racemization, etc.). In addition, complexes of amino acid Schiff bases are considered to constitute new kinds of potential anticancer, antitumor, antiradical and antibacterial reagents. On the other hand nuclear magnetic resonance imaging (MRI), has become a powerful tool for clinical diagnostics thanks to the development of a new class of pharmaceuticals... 

This study involved the synthesis, structural characterization and studies of gadolinium (III) hexaaza macrocyclic Schiff base complexes containing pyridine head and their decomposition in aqueous solution.There are many applications of lanthanide(III) macrocyclic complexes as medicine and in the biological systems, as magnetic resonance imaging (MRI) agents, and etc.These applications require that the Gd(III) complexes be resistant to gadolinium ion release under physiological conditions.
We considered planer macrocyclic ligands as a means to obtain highly stable complexes of Gd(III). Symmetric [2+2] Schiff base macrocyclic derived from 2,6-diacetylpyridine with amines would exhibit... 

The problem of launching a satellite to low earth orbit has been considered. Preliminary concepts such as satellite orbits, launcher missiles and their equations of motion, and traditional methods for guidance of launchers are reviewed first. Then a new method for optimizing the launch trajectory under non-ideal conditions is introduced in which the solution of a known ideal trajectory optimization problem is used as an initial guess for the actual optimization problem. Several methods for guiding a launcher to place a satellite in Earth orbit are presented next; they have been titled as (1) launch path re-computation outside the atmosphere, (2) prediction error minimization, and (3) output... 

It is well known that the classical continuum theory does not consider size effect in predicting material’s behavior, however at the micro and nano scales, this effect is not negligible and the classical theory has deficiencies at these scales. To take into account the size effect, higher order continuum theories introduce new material constants into the formulation. One famous version of these theories is couple stress which is applied in this research. This theory considers size effect of inhomogeneity by employing Characteristic length of materials. Quasi-static couple stress and classical dynamic approaches do not include explicitly the size of the material unit cell in the formulation... 

The aim of this study is to mimic water oxidizing complex to find new materials and also to understand their rules in this matter. To achieve this, manganese complexes containing 2,4,6-tris (2-pyridyl)-1,3,5-Triazine, 1,10-phenanthroline, 1,10-bipyridine, Schiff base, amino acids, 2,6-pyridinedicarboxylic acid, 2-pyridinecarboxylic acid have been synthesized and characterized by elemental analysis, IR, EPR, ESI-MS, electronic absorption spectroscopy, electrochemistry, X-ray diffraction and oxygen evolution in presence of oxone and Ce(IV). It is shown that the reaction between Mn(II) complexes containing 2,4,6-tris¬(2-pyridyl)-1,3,5-Triazine, 1,10-phenanthroline, 1,10-bipyridine,... 

The complexation between folic acid and the complexes of Cu(L)2 (L = Glycine, Alanine, Valine) were investigated using UV.Vis spectroscopy. The values of the equilibrium constant K and molar absorption coefficient Ɛ of the complexes were estimated in the aquation environment at various temperatures. The temperature dependence of the K can be used for the determination of the thermodynamic reaction quantities (∆G, ∆H, ∆S) for linear regression fits to the Van’t Hoff equation. The kinetic studies reveals that the stoichiometry of reaction were 1:1 for these systems. All reaction were endothermic and the values of the ∆H are positive. In all cases entropy increased and the values of the ∆S... 

The axisymmetric contact problem of a rigid inclusion embedded in the piezoelectric biomaterial frictionless interface subjected to simultaneous far-field compression and electric displacement is addressed. With the aid of a robust technique, the coupled governing integral equations of this mixed boundary-value problem are reduced to decoupled Fredholm integral equations with a constraint equation. A useful limiting case for the contact problem of transversely isotropic bimaterials is addressed. The present solution is analytically in agreement with the existing solution for an isotropic bimaterial. Selected numerical results of interest to engineering applications including the radius of... 

AdS/CFT Correspondence since it origination has found numerous applications in various aspects of Physics such as ion collision in Accelerators, Condensed matter Physics and etc. this orrespondence is a consequence of String Theory. In this project we have tried to analyze some of its applications in Condensed matter Physics and in the controversial phenomenon of superconductivity without resorting to the complexities of String Theory. Having applied this approach we have found a dual for it in Gravity and having calculated some common physical quantities and equations in these two sets such as Energy gap, Conductivity, London Equations and etc, we have tried to show the correspondence,... 

Human tracking is one of the most important research topics in computer vision with application in surveillance, crowd analysis, human motion and behavior analysis, and human-computer interaction. Availability of a large number of cameras has caused the need of designing automatic tracking methods. One of the most important challenges in automatic tracking is the occlusion of objects. Several methods have been proposed in the literature to solve this problem. One of the most popular and powerful methods is based on the usage of multiple views of the same scene in a cooperative manner between cameras. The most important challenge in using multiple cameras is the complexity of the tracker in... 

Artificial immune systems (AIS) constitute a novel area of bio-inspired computing. Biological models of the natural immune system, in particular the theories of clonal selection, immune networks and negative selection, have provided the inspiration for AIS algorithms. Moreover, such algorithms have been successfully employed in a wide variety of different areas, but have not been applied for chemical processes yet. One important part of the immune systems is lymphatic system. Clonal selection is one of the few algorithms that belong to the family of AIS techniques. Clonal selection algorithm is the computational implementation of the clonal selection principle. In this project, we have... 

During recent years, many researches on meshfree methods to solve differential equations and crack problem have been accomplished, and acceptable results have been obtained. One of these methods which is widely used in fracture mechanics specially in problems including crack is RKPM (reproducing kernel particle method). RKPM is one of the modern numerical methods in solving differential equations that has been lately introduced and developed. In this method, the genuine response of the system is replaced with a good approximation of the real response called ‘Reproduced Function’. The formulation of this method obviates the need for discretizing the domain by meshing with elements. In this... 

In this thesis, a new location-pricing model considering inventory costs has been developed. We should locate a certain number of distribution centers over the market area as a network and also determine the price and inventory of product in each distribution center for reach the maximum profit. A mathematical model was developed to maximize the earned profit. A hybrid algorithm is developed as a solution method including a tabu search algorithm for determining distribution centers location and an exact solution for determining pricing and inventory in each distribution center. Algorithm performance is compared against GAMS optimization solver and exact method.

 

Since the classical continuum theory fails to deal with the problems associated with defects, stress concentrators, and relevant deformation phenomena in solids, alternative approaches that can detect the atomistic nature of materials' fracture are required. The deficiency of the capture the size effect which yields delusively high values for some components of the stress field right on the edge of the stress concentrators, and its weakness in describing the complex interaction between small inhomogeneities, cracks and the like when they are only a few nanometers apart, are among some of the disadvantages of the classical approach. In recent years, however, atomistic methods are emerging to... 

The unsteady phenomena occur in rotors of helicopters, wind turbines and compressors. Investigation of the unsteady flow is a very important test, since it can affect and restrict the performance of rotors of helicopters and wind turbine's blades when operating at high angles of attack. Dynamic tests, such as pitching and plunging oscillations are one of the best methods for studying these phenomena due to the complexity of the unsteady flows. In analyzing the results of dynamic tests one must consider the interference effects of wind tunnel walls. Different investigations show that in dynamic tests, the interference effects of flow field around the model, wind tunnel walls and support of... 

Anomalous top quark interactions with gluon (tug , tcg) allow the production of single top quarks at the LHC. Two main sources of backgrounds which we took into account are W +1j and standard model single top production. In order to do it, we examine the reconstructed angular distribution of the charged lepton in the rest frame of W boson from the top quark. It is defined in terms of the angle θ_l , between the charged lepton momentum in the rest frame of the W boson and the momentum of the W boson in the rest frame of the top quark. Using this angular distribution of the charged lepton from the W boson in the top decay، we show that with the data of 10fb^(-1) of integrated luminosity and... 

Conventional two-dimensional photos are images of a three-dimensional scene. In fact, since the recording medium record only the intensity of the incoming light, information about the phase of the light couldn't be recorded and this results in making 2D photos from a real 3D scene.
In this research a mechanism for getting three-dimensional images in endoscopy and laparoscopy by Digital Holography has been designed based on the criteria standards in this field.