Sharif Digital Repository

Since 1906, after the earthquake of Messina in Italy, Italian engineers start developing a new method for increasing the resistance of a structure during an earthquake. With the limitation of time and technology, this method was acceptable for the time period. By developing the accelerographs and seismographs and the methods to process big data, new methods are developed and are being used in designing structures; new technologies allow engineers to analyze the performance of structures with ease. The studies in this research indicates that achieving the safety indices in any design require utilizing all dynamic properties of a structure such as period, stiffness and damping. In this... 

In this research, the risks of power plant projects are assessed with fuzzy approach. For this purpose, "Shirkooh Yazd combined cycle power plant" is chosen as the case study. First, the risks of power plant projects before the contract and during project execution are identified. Then these risks are categorized in a hierarchical breakdown structure. Subsequently, required information is collected from experienced professionals using questionnaires that used as the input data for risk qualitative analysis. In qualitative analysis, the risk probability and its impacts (containing time, cost and quality) are described by qualitative terms. After scaling them, the amount of each risk is... 

In recent years formation control of autonomous vehicles has been a well-studied topic, and the attention has shifted from the control of a single mobile robot to the control of multiple mobile robots because of the advantages a team of robots offer, such as increased efficiency, robustness against fault and damaging, and more systematic approaches to tasks like search and rescue operations, automated highways, survey and patrols, military missions, moving large objects and moving a large number of objects. Formation control means the problem of controlling the relative position and orientation of the mobile robots in a group according to some desired pattern for executing a given task. In... 

One of the novel methods of stabilization of nuclear waste is the use of vitrification technology. In order to stabilize high level wastes (HLLW) in glass, it is required that the elements are in their oxide form. Therefore, it is necessary to evaporate the waste and turn it into a solid form so that the elements can be converted into oxide form in the calcination furnace. Hence, one of the challenges of stabilization is the optimization of evaporation and calcination conditions. In this research, the parameters affecting evaporation were first investigated. Using laboratory measurements of application: temperature (110 to 180 °C), presence of nitric acid (0.5 to 4 mol/L), ratio of zirconium... 

This study used the emulsion liquid membrane method to investigate the extraction and separation of thorium from nitrate solution. According to the results obtained from the studies, Cyanex 272 was a suitable option for selectively extracting thorium. For simultaneous extraction and stripping of thorium from dilute aqueous solutions, an emulsion liquid membrane system consisting of Cyanex 272 as an extractant, Span 80 as a surfactant and sulfuric acid solution as a receiving phase (internal phase) was used. Emulsion liquid membrane method has high mass transfer flux due to high surface to volume ratio, which causes high extraction efficiency and fast transfer of thorium ions from its low... 

The present study aims to calculate the core inflation percentage using a SVAR model. Core inflation which is defined in policy-making, includes that component of measured inflation that has no (medium- to) long-run impact on real output but rather includes monetary and demand shocks. To this end, the VAR model is defined with 4 endogenous variables, namely production, inflation, money supply and exchange rate in addition to 2 exogenous variables, which are dummy (due to attracting the uneven behavior of exchange rate) and energy prices. Core inflation is produced using the results of the model estimation and the monetary and demand shocks. The results show that the core inflation usually... 

In the recent decades, cleanrooms have found growing applications in broad range of industries such as pharmacy and microelectronics. Concerns about negative effects of the contaminant exposure on the human health and product quality motivate many researchers towards understanding of the airflow and contaminant distribution through these environments. With an improvement in computational capacity of the computers, computational fluid dynamics (CFD) technique has become a powerful tool to study the engineering problems including indoor air quality (IAQ). In this research, indoor airflow in a full-scale cleanroom is investigated numerically using Eulerian–Eulerian approachand the results are... 

The subsidence phenomenon in the past years has caused many problems and issues for the agricultural lands, roads, power transmission lines, energy etc., due to different reasons including over use of groundwater resources and changes in climate. This phenomenon has been observed in different plains of the country including the Khorasan, Kerman, Hamedan, Ghazvin and Isfahan plains and has caused many damages to infrastructure and agricultural products in the mentioned regions. In this research the main factors which have affected the subsidence phenomenon especially reduced ground water table and climate changes in Ardebil plain, are taken into account and some studies which comprise... 

Innovations in laser, microwaves, and similar technologies have significantly advanced thermal treatments for diseases or even injuries concerning skin tissue. For a thorough understanding in the underlying mechanisms of bioheat transfer behavior of skin,a1D unsteady non-dimensional hyperbolic model of heat transfer through this tissue with metabolic heat generation which is subject to specific boundary conditions, is solved numerically using the finite difference method. A thermal shock is generated at the base of the tissue, which moves forward with a finite speed. A Numerical solution for a simple one-layer skin tissue is obtained. Then, the effects of various parameters, time step,... 

ADC is one of the key functional blocks of any mixed signal system and therefore must be optimally designed concerning power, performance, resolution and silicon area. Among different architectures have been employed up to now, successive approximation register ADCs are known as the ones with lower power, more simplicity and lower sampling rate. Benefiting from scaling down the CMOS technology results in higher sampling rate and lower power SAR ADCs replacing other types of ADCs. To achieve the desired ADC performance, efforts are usually focused on the improvement of circuit techniques as well as on the introduction of new or combinational architectures based on SAR ADCs. This thesis aims... 

The number of connected devices through the internet of things is increasing rapidly, which leads to adopting different communication technologies to provide connectivity of this large number of devices. The used communication technologies can be classified into the local area network, low-power wide-area network (LPWAN), and cellular network technologies. The receiver power has a critical role in the total power consumption of utilized transceiver chips in these technologies. Radiofrequency (RF) front-ends are often significant power-consuming parts of integrated receivers. Therefore, system-level design in which the overall specifications are distributed among RF front-end building blocks... 

Nowadays, customers hold a pivotal role as co-creators of value in service industries. Therefore, companies usually try to encourage customers to interact and co-create value effectively with the company or with each other. However, if a service provider fails to meet customer expectations, service failure occurs and may influence customer evaluations to co-create value. In this situation, companies usually try to redress the problem that happened to reduce their negative perceptions. Research related to the drivers of customers' value co-creation intentions has gained interest in recent years. However, there has not been an integrated view to simultaneously examine the negative role of... 

Nowadays, customers hold a pivotal role as co-creators of value in service industries. Therefore, companies usually try to encourage customers to interact and co-create value effectively with the company or with each other. However, if a service provider fails to meet customer expectations, service failure occurs and may influence customer evaluations to co-create value. In this situation, companies usually try to redress the problem that happened to reduce their negative perceptions. Research related to the drivers of customers' value co-creation intentions has gained interest in recent years. However, there has not been an integrated view to simultaneously examine the negative role of...