Sharif Digital Repository

In this study, the recovery of vanadium from the liquor solution of Iran Alumina Company was investigated using two-component and three-component nanocomposites including Zeolite A, Zeolite X, Magnetite and Amberlite IRA400. During this study, the synthesis of nanocomposites was analyzed using XRD, FTIR, FESEM and HRTEM methods. The effect of the percentage of zeolite A, zeolite X and Amberlite IRA400 as the second component in the magnetite-containing nanocomposite was evaluated. The findings showed that the best weight percentage for zeolite A, zeolite X and Amberlite IRA400 were 15, 5 and 50%, respectively. Then, the optimal composition for the three-component nanocomposite was selected... 

The main scope of this article is to identify Floer homology invariantsby means of Heegaard splitting of a 3-dimensional orientable manifoldY . Here by ” Heegaard splitting ” for Y , we mean decomposition Y =U ? U , where U and U are two balls with orientable g?handles,? ? ? ? ?gwich attached together on a closed oriented surface ? of boundary.gOne can identify this splitting by specifying two sets of oriented closedcurves ? = (? , ? , · · · , ? ) and ? = (? , ? , · · · , ? ) which live on ? .1 2 g 1 2 g gDesired invariants will be obtained by investigating g?order symmetricproducts of ? , denoted by SPg(? ) . in factT = ? × · · · × ? andg g ? 1 gT = ? × · · · × ? will play the role of... 

Today, many organizations and companies are confronted with enormous competition and uncertainty as a result of factors such as political issues, demand fluctuations, technological change, and financial instability As well as increasing business competitiveness, organizations focus on their core activities and lead to the use of outsourcing strategies, These factors are the cause of the formation of the supply chain And the lack of planning and identifying the factors that cause instability in the supply chain leads to its inaccurate performance. World-class organizations today have found that unintegrated production and distribution processes and poor communication with suppliers and... 

Distributed embedded systems are widely used in safety-critical applications, such as avionics platform and flight control system. Faults in such applications may cause catastrophic effect. Therefore, these systems must be fault-tolerant and must be designed not only to detect faults but also to recover from faults. Fault tolerance is normally realized on multi-processor system via temporal duplication (time-redundancy) or spatial duplication (hardware-redundancy) depending on the availability of the slack time. Slack time is defined as the difference between the deadline and execution time. Duplication is a common technique to achieve fault tolerance in safety-critical applications, but may... 

Energy consumption is one of the most crucial issues in embedded systems and memories are responsible for a considerable portion of it. Furthermore, leakage power is becoming the dominant part of total power consumption as the feature size of transistors is scaled down, therefore, the memory management must be improved in order to mitigate the negative effect of increased static power dissipation. In this study, a new memory architecture and a new data mapping algorithm are presented that reduce the energy consumption of multi-core embedded systems while respecting the timing constraints. We propose a novel two-level scratch-pad memory (SPM) based on STTRAM, which is a type of non-volatile... 

Many embedded systems must be highly reliable and have hard real-time constraints. Technology scaling has enabled integration of multiple fast cores in a single chip. This provides higher computation speed that can achieve low response time in real-time systems. However, shrinking transistor dimensions aggravates reliability threats. Furthermore, hard real-time embedded systems are usually subjected to severe power and energy consumption limitations imposed by battery and cooling units. Therefore, designing hard real-time embedded systems requires careful considerations of reliability and power/energy consumption issues. High reliability can be achieved through exploiting fault tolerance... 

The study of thermodynamics of small-scale systems or quantum thermodynamics has been recently receiving a lot of attention from quantum scientists in the field of quantum information. The main purpose of this thesis is to review the effects of quantum phenomena such as correlations, on the laws of thermodynamics and specifically on the efficiency of quantum heat engines. We first review some of the most important topics of classical thermodynamics such as the laws of thermodynamics, thermodynamic potentials and heat engines. The trade-off between power and efficiency for classical heat engines is investigated. It is shown that, this is impossible to have a heat engine performing with the... 

Internet of Things (IoT) is one of the most emerging fields in the computer science context. It is predicted that more than 9 billion devices will be connected to IoT networks by 2025. Considering the specifications of IoT devices such as low battery capacity and small memory, these networks face major challenges in energy consumption and reliability. One of the most important elements which have an indisputable effect on network efficiency is routing protocol. In this manner, IETF presented RPL in 2012. It is designed to create a robust network among IoT devices.Although RPL performs well in static networks, it is not designed originally for mobile networks and it has serious flaws in that... 

In this research the behavior of Circular Steel Tubes (CSTs) with corrosion under axial force and bending have been studied. There are several factors leading to corrosion in steel structures, especially marine structures that results in strength reduction of whole structure. Steel tubes are widely used in construction of on-shore and off-shore structures such as, oil rigs and platforms, oil and gas transmission lines. Current study focus on strength reduction of steel tubes with “pitting corrosion”. To this end numerical analyses using finite element software, Abaqus, have been performed. Therefore, utilizing verified models, the simultaneous effect of bending, axial load and corrosion on...