Sharif Digital Repository

Earthquake motions are among random excitation loads. For that we used random vibration approach to estimate response of multi-degree of freedom base isolated structures under ground excitation. Some models including linear model ,nonlinear Bouc-Wen and BBW models are studied for modeling the superstructure .Several base isolation models including the laminated rubber bearing, high damping laminated rubber bearing ,resilient-friction base isolator with or without sliding upper plate and the Electricity de France system, are studied . El Centro 1940 and Mexico City 1985 earthquake which preserve the nonstationary evolutions of amplitude and frequency content of ground accelerations... 

In this study, pulse electrodeposition of Ni-Fe composite coating with and without nano-TiO2 particle in sulphate bath was performed and effects of peak current density, frequency, duty cycle and type of current on their properties was investigated. Also effect of pulse parameters on the composition and amount of particles in coatings was determined. Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) analysis was used to study the morphplogy and structure of coatings. The chemical composition of deposits was examined by Energy Dispersive X-ray Spectroscopy (EDS) attached with Scanning Electron Microscopy and Atomic Adsorption... 

In the recent years, emerging vehicular ad hoc networks offer a wide variety of applications, including safety, convenience and entertainment. One of the beneficial applications in these fields is video streaming. However, according to the features like high mobility and loss of links, establishment of video streaming which requires stringent Quality of Service is a daunting task. In this thesis, the goal is introducing approaches in two levels, one for resilient video coding and the other one for network routing. For resilient video coding, the concentration is on the scalable video coding, which supports various applications for users with different requirements. The introduced approach... 

Reduced beam section connection was one of the connections that were introduced and prequalified by SAC project to replace pre-northridge connections. This connection reduces both flanges of the beam at appropriate distances from beam to column connection to make a fuse protecting welds from brittle fracture. The RBS is prequalified in limited span-to-depth ratio, for designing this connection for short and deep beams may effect its performance. Since these limitations are based on limited experiments, forty three numerical models were analysed to recheck them in this study. These models are verified based on two published experiments and are capable of predicting all known yield mechanisms... 

In recent years, due to the development of cities and population growth, the number of underground floors and the depth of excavations have increased. Sustainability of excavation and control of deformation due to excavation process has always been considered as one of the important issues in geotechnical engineering. One of the most commonly used systems for deep excavation, especially in urban areas, is the soldier pile wall with tiebacks. This system consists of anchoring on soldier piles that are performed at horizontal distances around the excavation range. The cables have two parts. Unbond and bond length that, when pretensioned, have the task of transfering load out of the wedge of... 

Periodontitis is a common inflammatory disease that affects the periodontium.Periodontium includes two hard tissues of cementum and alveolar bone and also soft tissue of periodontal ligament. The appropriate function is based on the consistency and accurate interaction of them. The complex structure, the low potential of the body for spontaneous healing, and technical problems such as bacteria accumulation, limited access, and small operating field cause no complete treatment can be achieved until now.In this project, at first collagen type I was extracted from Bovine Achilles tendon. Then, polymer modification was done to 39.95 µg/mg (Tyramine/ Collagen). An In situ gel based on modified... 

Today, communication sciences are advancing very rapidly; one of these advances is mobile location determination, means finding position of a mobile station. there are some method to location determination; one of these methods is Signal Strength (Power of Arrivals); In this research, Mobile Location Determination using Signal strength measurements in a Location grid will be describe; In this method there is a Mobile Location Server (MLS); In MLS, there re comparable records in database which have been collected from Location grid. When a MS needs to be located, its signaling data (fingerprint) is transmitted to MLS; In MLS, the fingerprints are compared to Data which is store in signature... 

The present study was aimed at investigating the use of platinum and platinum nanoparticles stabilized on zeolite as catalyst for the reduction reaction of p-nitrotoluene as one of the dangerous pollutants. The adsorption properties of platinum based on zeolite have been studied for some heavy metals. Monodispersed platinum nanoparticles were synthesized through reduction of H2PtCl6 by ethanol in the presence of polyvinyl pyrrolidone (PVP) as a stabilizer, and then were immobilized on four types of zeolites. The study then focused on elaboration of the catalytic activity of the nano catalysts under different operational conditions. In order to investigate the catalytic properties, operating... 

Energy Harvesting is one of the techniques which can be utilized in Green Communications and increase the wireless networks lifetime. In an EH system, each resource is supplied with the energy harvested from the environment. When we confront with a situation that the users of one channel want to increase their rates and this action negatively affects the other user’s rates, the user’s cooperation problem for obtaining a fair rate will be created. In this study, at first we consider a Multiple Access Channel and we assume that the energy resources of transmitters are harvested according to a known probability. In addition, we assume that the transmitters do not know the instantaneous amount... 

The spectrum of a graph is related to many important combinatorial parameters. Let (G), ′(G) be the maximum number of edge-disjoint spanning trees and edge-connectivity of a graph G,respectively. Motivated by a question of Seymour on the relationship between eigenvalues of a graph G and bounds of (G), we use eigenvalue interlacing for quotient matrix associated to graph to get the relationship between eigenvalues of a graph and bounds of (G) and ′(G). We also study the relationship between eigenvalues and bounds of (G) and ′(G) in a multigraph G. In the first chapter we prove eigenvalue interlacing and give several applications of it for obtaining bounds for characteristic numbers of... 

One of the most important methods for recycling of spent Li-ion batteries is acid leaching that various parameters affect it. In this work, influences of effective parameters on the percent of cobalt and lithium recovery with application of design of experiments (response surface methodology-central composite) were investigated and then cobalt nano oxide as the by-product synthesized by pulsing lectrolysis. In the first Phase, effects of parameters such as sulfuric acid oncentration: 2-6 molar, hydrogen peroxide volume percent: 5-10%, S/L ratio: 20-50 g/L and temperature: 50-80°C on cobalt and lithium recovery were investigated and finally an adequate model presented. For all experiments,... 

In this study, a mathematical model for health-care facility location in two level and multi-services has been described. The facilities has two levels of clinic and hospital that has inclusive hierarchy property. In clinics, only outpatient services delivered. But, in hospitals in addition to handle outpatient services, inpatient services and emergency services are provided. In this research, we practice on queuing theory in order to consider the serious uncertainties in the health service, for instance, random demand and random service time, and by the help of which the criteria for considering the service level is calculated. Then by using applicable change variable and service level...