Sharif Digital Repository

Masonry buildings are one of the most vulnerable structures against earthquakes, and therefore their seismic response should be evaluated in order to mitigate casualties in the future. Although there are numerous experimental and analytical studies on these buildings, few have aimed on Confined Masonry (CM) buildings to simulate and predict their seismic performance. To estimate damage, assess vulnerability and choose the best retrofitting method, fragility curves can be utilized as a powerful tool. In this paper, the hysteretic behavior of two typical CM walls with and without opening is calibrated in both In-plane (IP) and Out-of-Plane (OOP) loading directions making use of OPENSEES... 

Interconnects in SOFC’s has oxidation problems which is Because of high temperature operation. Also Cr migration to cathode make chroumiom poisoning problems and all of this affects SOFC’s efficiency. To solve this problem researchers decided to use some protective coating on interconnect. The best group of coatings is Mn-Co Spinels. In this thesis (Mn,Co)3O4 spinels was synthesized via solid state reaction. MC reffered to Mn1.5Co1.5O4 was calcined at 850°C and then sintered at 1200°C. It’s electrical conductivity measured by 4-point probe DC method. It had the lowest ASR (17mΩ.cm2) among other stochiometries. To reduce the sintering temperature, Cu and Y was added as dopants. Among the... 

In this work hydrometallurgical route for processing spent commercial catalysts (Co/Al2O3) are investigated for leaching the Cobalt component. The used catalysts were initially pre-oxidized at 500 °C and 5 h in order to eliminate coke and other volatile species present. Pre-oxidized catalysts were dissolved in solvents such as H2SO4, HNO3, HCl and H2O at 80-90 °C, and the remaining residues separated from the solution. These experiments were performed at different concentrations, presence and absence H2O2 solution. Also effect of reflux on leaching process investigated. The result show the yield of the pre-oxidized catalysts extracted with highly concentration of extractant is higher than... 

Vehicular ad-hoc networks are forms of mobile ad-hoc networks in which every vehicle can be smart and communicate with surrounding cars and roadside units. The main differences between these networks and mobile ad-hoc networks are high mobility and rapid changes in network connectivity as well as higher scalability and extensibility. The main goal in the vehicular ad-hoc networks is to increase safety for both the passengers and the driver. Since there are high mobility and rapid changes in network connectivity in such networks, there may be no path from a specific source to a destination, so design of new protocols to guarantee parameters such as reliability and less overhead would be... 

This research focuses on the development and implementation of a wireless power transfer system based on magnetic induction to power wireless neural recording devices in experiments where animals move freely in a cage. The main goal of this research is to reduce the weight of the recording devices by eliminating the battery and using wireless power transfer. By removing the battery and employing magnetic induction, the final weight of the device is minimized, eliminating the need for battery replacement or recharging, and reducing the negative impact of the device's weight on the natural activities of the test animals. Power transfer for wireless neural recording devices is achieved through... 

Pretreatment of nuclear waste for valuable and limited uranium resources in the nuclear industry as well as environmental protection is imperative. Wash the affected parts of the Natanz uranium enrichment plant uranium centrifuges with a standard cleaning solution of citric acid, a liquid waste is generated in this study, the preparation of these residues using supercritical water oxidation (SCWO) and near critical (HTWO1) was studied as a result, the optimum operating conditions, and conditions of solvent extraction has been studied. In the result, the optimum operating conditions, and conditions of solvent extraction has been introduced. Also in the UCF2 as a liquid waste contaminated with... 

Separation of the effects of the initial horizontal stress and relative density on the cone tip resistance in the sandy soils has been a complicated issue for many years. On the other hand, there is no reliable method for determining the in-situ horizontal effective stress based on the piezocone measurements in the cohesive soils, and the empirical correlations suggested in the literature produce no more than a rough estimation.Considering the aforesaid issues, an attempt is made in this thesis to provide a new innovative solution for determining the in-situ horizontal (effective) stress in the sandy and clayey soils according to the CPT measurements. In this regard, at first, numerical... 

According to increasingly utilization of different frequency spots, RF receivers are allways under the threats of compression and desensitization because of large out-of-band or in-band blockers. The IC technologies afford fast, low-resistance switches as scaling keeps going on. With this mind, the Linear Periodic Time Varying circuits, in which the switches play the most dominant role, will be a sensible candidate for the concerns of blocker detection and rejection. Furthermore, nowadays’ receivers should be reconfigureable so as to be tunable at different frequency bands and satisfy contrastive standards. In this regard, the LPTV filters provide vast range of tunablity not only with... 

It is possible to unload a transmission line for a while. In line restoration voltage and current of the line will have some dynamic changes. So the apparent impedance of distance relay will have dynamic changes. These changes may cause some bad results including entrance of apparent impedance to the operational zones of distance relay and even relay tripping. Consequently if relay trips, the line restoration process will stop and may not be possible.
So we want an algorithm to distinguish line restoration from short circuit condition and block the relay. This algorithm must be able to stop blocking if there is any fault in the operational zones of the relay.
In this thesis an... 

In recent years, due to urban expansion and population growth, number of floors and excavations depth has increased. Stabilization of excavations is one of the most important issues in geotechnical engineering. Today, one of the most widely used methods that is used in deep excavations is brace soil by steels and pretension them. In this thesis tries to evaluate static behavior of flexible supporting structures with pretension anchors by using PLAXIS2D, FLAC3D and GEOSTUDIO softwares. The objective of this modeling is better understanding the static behavior of walls, comparing the two and three dimensional modeling and the effect of corners of excavation on deformation. The results shows... 

Nowadays, according to environmental issues and fuel economy in internal combustion engines, the tendency to use of electrical and hybrid-electrical propulsions has become more than the past. On the other hand, still there are some problems like distance and charge time in electrical propulsions. Among them there are Hybrid-electric propulsions that have the benefits of two other propulsions. These propulsions are classified into three categories: series, parallel and series-parallel.Propulsion hybridization will change the cooling system. Internal combustion engine, electric motors, inverter and batteries operate at different temperature levels. So more than one cooling circuit with its own... 

The digital nature of Successive Approximation Register (SAR) Analog to Digital Converter (ADC) suits them for the new technologies with small gate length and low power applications. Applications such as ultra-wideband receivers, satellite receivers and high speed serial links demand medium resolution and high sampling rate ADCs. Due to binary search algorithm speed limitations, SAR ADCs belong to low to moderate speed category. In this thesis time-interleaving and two-bit-per-cycle technique are used in order to increase SAR ADC sampling rate. These techniques are both sensitive to offset and if the comparators used in SAR ADC have different offsets signal-to-noise-and-distortion will be... 

Mobile technology has become Ubiquitous and common in all over the world from the first years of 21st century. Mobile has been used as a strong media in marketing and specifically in advertising due to it’s unique features and various functions. Currently (2008) mobile media is not used very aggressively in Iran. Considering the quick expansions of mobile networks in Iran and growth of subscribers, it is anticipated that Mobile will affect many businesses and consumer market very soon in Iran. This study is the first academic research in the country on Mobile advertising via SMS. The purpose of this thesis is to provide the better understanding of the Mobile advertising via SMS in high... 

Variation of the input driving power can cause in some varactor and BJT frequency multipliers parametric instability. If parametric oscillations are present in the circuit, output phase noise of the multiplier degrades remarkably in some specific driving levels. Phase noise of the varactor and BJT multiplier is calculated by the conversion matrix method using generalized nodal analysis. By the conversion method the phase noise degradation can be predicted precisely. In the calculation of phase noise the effect of the noise sources that are modulated by the large signal drive and the conversion of components of the internal noise sources of the device to the output spectrum due to circuit... 

Ridge gap waveguide is a new technology with low loss and high power handling capability in millimeter wave(mm-wave) frequencies. In this technology there is no need for electrical connection between the constitutive parts and using dielectric material as a substrate. This thesis focuses on the capabilities of this technology in realization of devices used in communication systems at the mm-wave frequency. Novel devices based on this technology have been designed, fabricated and tested. The main goal of the thesis is realization of the whole RF front end of a communication system in Ka band based on this technology. So at first step, a ridge gap waveguide transmission line is evaluated and a... 

Cache networks play a key role in today’s Internet. Inspired by the successful deployment of caching in content delivery networks (CDNs), pervasive caching now is a fundamental concept in storage-assisted future Internet architectures, e.g., information-centric networks (ICN), and 5G. However, despite the clear and increasing economic advantages of caching for the network operators, it does not take place efficiently due to various problems. The emergence of in-network caching has created new challenges for modeling and performance evaluation of networks. In addition, content providers (CPs), who alone have the detailed demand data required for optimal content placement, have no natural... 

The two-dimensional composites are benefited from different advantageous; however, they may not be good enough in terms of strength along the thickness, manufacturing speed, cost management and resistance to delamination. To overcome these unpleasant challenges, the three-dimensional composites are defined as having a 3D pattern of yarns which not only includes yarns along the length and width, but also in thickness or vertical direction. One of these common types of composites is 3D-orthogonal woven composites. In this comprehensive research study, the 3D orthogonal woven composite modelling is conducted through a specialized and advanced software, TexGen software. Then Voxel mesh were... 

In this study TiO2/SiO2 thin films were prepared by sol-gel method from Tetra isopropylortho Titanate(TIPT) as the principle of TiO2 material with Tera ethoxysilane(TEOS) as the principle of SiO2 material to achieve high scratch-resistant , antibacterial and self-cleaning surface area under the effect of various percentage of SiO2 . Film deposition was carried out using a dip-coating technique and heat-treatment was used at 700ºC to achieve crystalline of films with excellent adherence the of substrate.
The surface morphology of the films has been observed by Scanning Electron Microscope (SEM) and the tribological properties of the surface were investigated by Atomic Force Microscope... 

Ball mills are a category of industrial mills used for crushing and grinding non-metallic materials into powder. In these mills, as the mill rotates, steel balls move and by falling on materials, the process of crushing and grinding takes place. The mismatch between the rotation speed of the mill and the volume of balls inside it can result in ineffective collisions between the balls or between the balls and the inner protective layers of the mill, causing damage to the balls and liners and leading to repair costs and loss of production. The aim of this project is to design and prototype an intelligent system for monitoring the ball mass inside the mill to increase production efficiency and... 

Web service technology is becoming increasingly popular since it is very bene?cial in di?erent types of applications. Due to a dramatical increase in the number of developed web services, the service discovery process has become crucial for using web services e?ciently. Service is an adaptive, self-describing, modular application, which may be used in either web or an internal network. Service providers should o?er the services along with a description ?le called advertisement explaining the speci?cations and functionalities of the service. Traditional service discovery methods are based on syntax and keyword matching, which may not satisfy the requester’s desired requirements and will...