Sharif Digital Repository

With the popular choice of using underground structures and tunnel in big cities and with significant damage in recent large earthquake; therefore more attention is given to the behavior of the underground structure in seismic area. The purpose of this thesis is to present the Soil-Tunnel-Structure Interaction analysis performed for different dynamic load condition. Therefore we modeled a 3D intersection part of two different tunnels in homogeneous soil by ABAQUS software. The soil and concrete structure of tunnel is modeled by three dimensional solid finite elements and the boundary of soil is modeled by three dimensional infinite elements with 8 nodes. The results demonstrate the geostatic... 

The aim of this study at the outset is synthesis of ligands with the ability to bridge formation between two groups i.e. C60 and Cobalt Schiff base complex (CoSALEN). Hence, four Schiff base ligands with pyridine electron donor moiety in one side, and such electron donor moiety pyridine, phenol and aniline in another side were synthesized and characterized by elemental analysis, 13C¬NMR, 1HNMR and IR Spectroscopy. In next step the interaction of these Schiff base ligands with CoSALEN complex and Fullerene C60, in the mixture of two solvents, i.e. toluene/dimethylsulfoxide and benzene/methanol was explored separately by UV-Visible Spectroscopy and their kinetic studies were also undertaken... 

This research concerns a study of the interaction between tunneling and adjacent structures. Analysis is performed using a full two-dimensional finite element model, which takes into consideration the presence of adjacent structure with regard to distance to tunnel and diameter of tunnel during construction of the tunnel. The soil behavior is assumed to be governed by an elastic perfectly-plastic constitutive relation based on Mohr-Coulomb criterion with a non-associated flow rule. The research is composed of two parts. However, compatibility of each method with beam and solid continuum element models in two dimensional finite element (FE) analysis was investigated. The first part describes... 

Folic acid is a pterin derivative containing a glutamyl moiety and essential for biological reactions. Pterins are a class of heterocyclic compounds with unique structures and biological functions. Tetrahydrobiopterine has been known to be essential for catalytic hydroxylation of aromatic amino acids by metal ions-containing aromatic amino acid hydroxylases. Metal ions at the active site of these enzymes have been inferred to be closely associated with the pterin cofactors in the catalytic reactions.Information on pterin-metal interaction may give clues to the role of metal ions in enzymatic reactions. With these points in mind, studies have been conducted to verify the formation of ternary... 

It is the main idea of present thesis to provide a micromechanical method as a general treatment for several fundamental problems of the piezoelectric inhomogeneities. For initial demonstration of pertinent methodology, a single piezoelectric inhomogeneity of ellipsoidal geometry, under non-uniform far-field loading is considered. Accordingly, it is taken equivalent to elastic and dielectric inclusion problems connected by proper eigenstrain-electric field. This approach is named the electro-mechanical equivalent inclusion method (EMEIM) and requires that the electroelastic fields of the inhomogeneity to be equal to fields of the equivalent inclusions. Afterwards, the complex problem of... 

Integration of transportation demand management (TDM) policies, as a realistic and effective approach, is a challenging issue in urban policy studies. This study examines the role of transportation demand management (TDM) policy packages on commuters' mode choice in the city of Tehran. The analysis is based on the results of stated preferences survey developed by efficient choice design as a specialized type of fractional factorial design approach. Five policies, namely increasing parking cost, increasing fuel cost, cordon pricing, transit time reduction and transit access improvement, are assessed in considering six modes of travel to work place. A multinomial logit model has been developed... 

The role of the lumbar muscles in maintaining posture and balancing externally applied loads has been studied for many years.preliminary studies used electromyograpy (EMG) to establish a relationship between trunk posture and muscle ativity.so developing a better undrestanding of the functional role of those muscles. Determination of lumbar muscle forces, will have an important role in reducing low back pain I future.For this reason,reaserchers have done many studies for understanding the resistence and function on the musulosketal system bye using of various protocls and have utilized of various biomechanical models for determining the effects of applied externally loads on lumbar... 

This work is concerned with new methods for decomposing large scale systems into disjoint neighborhoods with specific size determined a priori by the communication load of the Jacobi based distributed optimization technique. This iterative optimization technique has the following features: it handles hard control input and state constraints; and for convex optimization problem, in the limit, its solution converges to the optimal solution. The proposed decomposition techniques cluster subsystems based on the strength of control inputs interaction. Three techniques are proposed. The first technique is an extended version of REGA. The second is an extended version of Participation... 

In recent years, application of silica nanoparticles for wettability alteration of reservoir rocks as an effective approach in enhancing oil recovery from petroleum reservoirs is introduced. However, in this area, lack of fundamental studies to provide a clear understanding about the interaction between these nanoparticles and carbonate rocks (as the predominant reservoir rocks in the world and Iran), which is of particular importance, is sensed. Therefore, the main purpose of this dissertation is to present a mechanistic investigation about the interaction of silica nanoparticles (the most used nanoparticles) with carbonate rock from theoretical and experimental viewpoints. To better... 

The study of quantum effects for black holes indicates that they can thermally radiate different particles.In this thesis, we investigte the radiation of charged spin zero particles and show that these particles can interact with each other and as a result produce photons.These produced photons make a correction to the emitted photons from the black hole. By caculating this correction, we conclude that interactions have a small effect on the radiation spectrum of the photon  

In this paper, the elastic response of a surface-stiffened transversely isotropic half-space subjected to a surface normal load is addressed. The half-space is reinforced by a Kirchhoff thin plate bonded to its surface. Two different boundary conditions are considered across the plate-half-space interface: (i) the classic approach in which the plate in-plane deformation is neglected by writing the interfacial boundary conditions across the plate mid-plane, and (ii) the refined approach that considers the in-plane deformation of plate due to bending by writing the boundary conditions across the bottom face of plate. By virtue of appropriate displacement potentials, the complete set of elastic... 

In this research with Finite Element Methods in ABAQUS, numerical modeling has done in three-dimensions, which can be used to determine the effect of different factors on the surface settlement. Also, various factors such as geotechnical conditions, tunnel diameter,tunnel depth, the impact of the thickness of the segments and the amount of eccentricity of the structure relative to the longitudinal axis of the tunnel considered in this study. Face Pressure Supports, and Grout Injection Pressures are taken into account, too.Tunnel drilling causes a change in the displacement area and creates a changing zone around the tunnel. In this regard, not only adjacent buildings will be affected by... 

Today, the digital transformation has increasingly confronted software development companies with numerous requests for the production of custom software. Over time, these companies have realized that paying attention only to the technical aspect is not enough for delivering a product that functions correctly; the social dimension must also be considered. Consequently, many agile software development methods have been developed. However, an important point to note is that implementing and maintaining these methods involves many intricacies, with the most significant being the management of interpersonal relationships. With the continuous expansion of technology and the advancement of... 

Organizations increasingly prioritize and utilize their intangible assets in a combined manner to achieve sustainable competitive advantage and success in a volatile market environment. In this research, the most important intangible assets of organizations have been identified. Using the Generalized Method of Moments, a suitable regression method for the statistical analysis of panel data, the impact of intangible assets on organizational profitability—specifically the return on assets—is examined separately and simultaneously across manufacturing and service industries. These assets include innovation, employee engagement, and customer satisfaction. The population of this study consists of...