Sharif Digital Repository

Green tea has been receiving significant attention in recent years due to its high content of catechins; Epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC) and especially epigallocatechin gallate (EGCG). As powerful antioxidants, these compounds are believed to have several health benefits. In this study, we used supercritical CO2 with ethanol as co-solvent to extract catechin derivatives from green tea and we investigated the effects of experiment parameters on the extraction. Experiments, designed according to Taguchi algorithm, were conducted with green tea particles of four average diameters of 1500, 855, 605 and 427.5 µm, in an interval of 35- 55 ̊C for temperature and... 

provide about 67% of a hospital’s profit. Hospital managers are interested in decreasing the costs as well as increasing the customers’ satisfaction level. In this Thesis, four Mixed- Integer Programming models for planning and scheduling operating rooms are proposed. In the main, the problem is presented in two phases. In The first phase, model assigns the date and the room to each surgical and in second phase the model determines the sequencing of the assigned operation cases. The effects of using three different scheduling strategies (Block and Open and modified block) for assigning operating rooms to surgeons on the planning of surgical cases is studied. Then we proposed one phase model... 

According to recent advancements in digital circuit technology and new constraints for digital systems, scholars have researched to find a replacement for traditional copper links that is used to connect the embedded processing elements in a chip. Optic NoCs and wireless NoCs are two promising solutions to overcome challenges in traditional NoCs.
In this thesis, an innovative 3D NoC architecture is proposed which consists of four 2D mesh-based networks and they are connected via four wireless sub-networks as backbones. It is estimated that, the proposed architecture shrinks the power consumption at least 35 percent relatively due to the gate-level simulations. Thus, a better scaling and... 

The airport terminal is difficult to plan and design due to the different components and the intricate complexity of its parts. At the airport terminal, we face a queue system which simulation is always a good way to analyze. In addition, computer simulation using modern softwares with the capability to model different types of systems, including the airport terminal, while being less realistic than analytical models, is less costly than operational Exercise.In this study, a supportive approach for better and specific management of Iranian airport terminal buildings with discrete-event simulation is proposed, considering the need for managing the airport terminals building in the country and... 

In a macro view point, it can be said that housing demand in recent years is making the construction industry one of the main sectors of Iran’s economy. On the other hand, analysis of seismic risk in the country with regard to the geological conditions, the faults, and the seismic records of mega city of Tehran is depicting the delicate location of the Iranian capital. This city is selected as a case study in this thesis that has a high probability for the event; where this event has also been classified as a devastating earthquake ever. Due to the involvement of private sector in construction industry, the need for establishing a system of strict control on quality of construction of the... 

Limited water resources in Iran have made dams an important part of the country’s infrastructure. As a result of the large number of in-progress and expected dam projects in the country, consideration of sustainability factors during planning, construction and operation phases of dam projects can create significant economical, social and environmental impacts in the long term. To come up with an inclusive sustainable development, new sustainability assessment approaches seek for sustainable development at the entire project’s life-cycle; they are looking for sustainable development at all design, construction, operation, maintenance and even demolition phases. In this research we have... 

Limitations in coherence time and gate fidelity are among the most significant obstacles to scaling superconducting quantum computers, both of which are influenced by system noise sources. To control noise, one must first recognize the noise sources in superconducting qubits and then address methods to manage them. The main noise sources in superconducting qubits include charge noise, flux noise, thermal noise, photon number fluctuations, and noise caused by quasiparticles. Control methods include improving superconducting materials, enhancing superconducting chip fabrication techniques, cooling, noise filtering, quantum error correction, and more resilient qubit design and engineering. In... 

Nowadays, most of businesses are becoming computer-based. This trend causes the organizations to become more vulnerable to internal and external threats. Internal threats are done through insiders. Insiders unlike outsiders have capabilities which aid them to easily carry out their illicit activities. Unfortunately, most of research in computer security has focused on the outsider threats, whereas the most damaging is the result of insiders’ illicit activities.This dissertation addresses three primary necessities of the research in the area of insider threat: a consistent definition of insider threat, a classification of types of insider threats, and a classification of vulnerabilities which... 

This project focuses on the Tennessee East-man challange problem(TEP) and the impact of setpoint changes and controller tunning on plant performance and profitability. TE has four major units. it is an unstable system due to the reaction within the reactor and a recycle streamcausing snow ball effect. As a result the control of this system is not easy. The study has been conducted along two main directions. First, selecting the optimal values for the setpoints and applying them in the simulation. secondly, try to find better parameter for controller in simulation. Simulation is based on working of Ricker. In TEP like the other multivariable systems, it is ameanable to use a centralized... 

Decentralized control is a typical method for the design of industrial MIMO control systems. However, in most multivariable systems, the existence of large interactions limit the achievable performance of such controllers. In the Nyquist Array design method proposed by Rosenbrock, the system interactions can be reduced using a precompensator, such that a decentralized controller may be used with acceptable performance. A well designed pre-compensator will effectively decouple the system and the multivariable systems may be considered as a set of SISO systems. It is therefore obvious that the key element in the Nyquist Array design method is the design of the pre-compensator. There are two... 

Integrity of closed-loop systems with integral action control is characterized by using a series of successively more difficult to obtain conditions: Integral Stabilizable (IS), Integral Controllable (IC), Integral Controllable with Integrity (ICI), and Decentralized Integral Controllability (DIC). The IS condition requires that for a Linear Time-Invariant (LTI) finitedimensional (FD) plant, G(s), one finds a stabilizing decentralized controller with integral action. For G(s) to be IC, in addition to being IS, one should be able to reduce the gain of
all control loops by the same factor from a finite value to (but not including) zero without introducing instabilities. ICI requires that... 

Intraction in multi input multi output (MIMO) system makes control of these systems difficult.There are two ways to control such systems; Centralized and Decentralized control. One way in which a centralized controller is designed is using a precompensator. With application of the pre-compensator, the MIMO sytem is decoupled into several SISO systems and one can control these seperatly. Almost all previews methods for the design of pre-compensator assume that the model of the plant containsno uncertainties.In this thesis a new method is proposed which takes into account model uncertaintes in the design of the pre-compensator.The form of the uncertainties considred an interval-parametric  

Multivariable control systems as used in the industry usually contain integral action in order to improve tracking of the output with respect to step reference changes. These systems are usually subject to input saturation due to actuator or sensor nonlinearities. The aim of this work is find the conditions for the integrity concept of such multivariable system, e.g. IS, IC, ICI and DIC. First we develop the conditions on the controller gains necessary stabilize the systems and then show that these conditions can changes when one examines integrity conditions  

The servomechanisms have wide industrial application such as robotics, Computer Numerical Control (CNC) machines, automated manufacturing and solar tracking. Several methods have already been proposed for servo motor control that the most important of them are Proportional Integral Derivative (PID), H2/H--, intelligent based controllers, and model predictive control. Problem specifications and user requirements, will determine the appropriate approach in each case. The aim of this thesis is construction of a real-life camera stabilizer to be used in the motion picture industry. Effects of base movement on the performance should be decreased by choosing appropriate sensors and control...