Sharif Digital Repository

Using field assisted dissociation model and with a classic view the dissociation probability is calculated when it a molecule is exposed with a Ti:sapphire laser with wavenumber of 800nm and the energy of . using gradient optimization method we find a tailored two rectangular laser pulse for controlling the dissociation of C-H bond of . Using classical method reduced the complicacy of solving schrodinger equation. In our optimization method in contrast with the usual controlling method experimental data is not needed and this reduced the controlling costs.

 

By taking a new sight into the system dynamic equations, the controllers are designed based on the simplification and converting higher order dynamics to the first order systems. This issue not only simplifies controller design but also stabilize system in all operational points. Moreover, proposed controllers are applied to the parallel Active Power Filters (APFs) because of the new trends in modularizing of APFs. On the other hand, the IEEE-1459 standard has proposed new definitions for the power in unbalanced and non-sinusoidal conditions and it stimulated researchers to use this standard for controlling APF directly. However, the proposed definitions are based on RMS values and... 

Nowadays, thin film alloy deposition has much importance. These alloys are used for various opto-electronic device applications such as liquid crystal displays, flat panel displays, plasma displays, solar cells and computer memories. Exact control of elements ratio in alloy is one of the important issues in deposition of thin film alloys. In alloy deposition with electron beam gun method from its elements, uniformity improvement of each layer is a way to maintain elements ratio in different parts of sample. This uniformity has much importance especially in optical coatings such as high quality antireflection coatings, highly selective filters and low loss reflectance coatings. In this... 

In this thesis departure programming are studied in general state and takeoff programming studied in special state. Departure programming consists of several parts that decisions for each part may influence in the other parts. Because of unforeseen delays this problem is a dynamic problem. Holding area is a part that overtaking operations performance before takeoff. An initial sequence obtained from ground controller. A heuristic algorithm that used in this thesis is a hybrid of constraint satisfaction and dynamic programming for minimizing sum of the total delays. The performance of the heuristic algorithm is compared with tabu search algorithm. The result shows that the proposed algorithm... 

In industries there are many nonlinear processes which cannot be easily controlled with classical methods. Model predictive control is a useful method for nonlinear processes which not only has high efficiency, but also extension of this control to interferential multi variable case, with constraint on the controlled and manipulated variables and other problematic dynamic specifications such as slow dynamics and inverse response is very simple. Industrial polymerization processes are regarded as significant nonlinear processes. Optimization and control of polymerization reactors have considerable importance in process applicability and in economics. The molecular structure of polymer such as... 

The quality characteristics of both manufacturing and service industries include not only the variables but the attributes as well. While a substantial research have been performed on auto-correlated variables, no attempt has been fulfilled for auto-correlated attributes. Ignoring the imbedded autocorrelation structure in constructing control charts cause not only the in-control run length to decrease, but also the false alarms to increase. To overcome these shortcomings, in this research, an auto-regressive (AR) vector first models the autocorrelation structure of the process data. Then, a modified Elman neural network is developed to generate simulated data using the ARTA algorithm. Next,... 

Integration of radio transceivers results in developing low power low cost wireless systems and allows delivery of multimedia contents to battery-powered mobile terminals. Portable reception of digital video for hand-held devices is one of the applications, for which, some telecommunications standards have been developed in the recent years. This research deals with the integrated implementation of the radio frequency parts of the digital video receiver, especially the frequency synthesizer. The key aspects of the digital video reception system are the required signal to noise ratio, which is relatively high, wide band input signals and strong interferers in the receiving band.
In... 

Hierarchical voltage control is one of the conventional kinds of coordinated voltage control schemes which has been studied in some countries in the last decades. In this method network is divided into several voltage control regions and in each region voltage profile is controlled near optimal level, satisfying the economic and secure goals of the network performance. In this thesis, after the explanation of the main concepts of this scheme, its effects on the network voltage control is assessed and its performance is improved. First the primary concepts of hierarchical voltage control are explained. Then, the methods of the control regions determination and pilot nodes selection are... 

This research focuses on the dynamic analysis of an exoskeletal system to assist a paraplegic motion. Research in powered human exoskeletons began in the late 1960s, almost in parallel between the numbers of research groups for different applications. The main challenges for the recent work in exoskeletons were focused on the design and demonstration of an initial prototype. To this point, the reported advantages of the autonomous exoskeleton systems are largely anecdotal. Indeed, there is a marked lack of published quantitative performance results for exoskeleton devices that reportedly improve human locomotion. Considering this, there are many design challenges remained that may lead to... 

An automatic air traffic controller system is designed in this research. The major goal is to aid the human controller in decision making at real air traffic control situations. The air traffic system is modeled by queuing theory. Since respond rapidity is very important in air traffic control, so the fuzzy logic is utilized to construct a rule-base. This rule-base determines optimum policies while considering the operational matters, minimum separation distance requirements, air traffic controller techniques, and work-load. This project is an initial design for air traffic automation system which considers scheduling optimality as well as delay reduction. The case study is done on Denver... 

The main objective of this project is to take the first steps in designing power plants governor in Iran. In this work, we obtain a realistic model of a hydro-power plant including hydraulic characteristics from the dam to the outlet tail water, mechanically including: the turbine, the gates and all mechanical and dynamic parts, and electrically including generators, transformers and the consumption network. The model is used to simulate different working modes of turbine operation. The Bond Graph method is used for deriving the system equations and MATLAB software for simulations. A conceptual design of the governor is done and the governor model is combined with the turbine model. Using... 

In the present study, an adaptive sliding mode control method was employed to control a fish robotic system using the method of hardware in the loop. Following the introduction of the nonlinear model for the robot, elongated body theory, suggested by Lighthill, was used to analyze fish movements. Lighthill’s theory inspired from slender body theory in aerodynamics scope could be viable to exercise upon the carangiform mode of swimming. By simplifying Lighthill’s equations in planar motion of fish robot, the number of degrees of freedom exceeds the number of the control variables. In view of the fact that the presented model is an under-actuated model, there exist some parametric and... 

ZnFe2O4 nanoparticles have been successfully prepared through a controlled microwave–assisted co-precipitation as well as conventional co-precipitation. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were used for the structural, morphological and magnetic investigation of the product. Average particle size was obtained as 12 nm from XRD. Catalytic activity of ZnFe2O4 nanopowder for O-acylation of alcohol and phenol has been investigated. A trace amount of ZnFe2O4 has been effectively used as a nanocatalyst for the acylation of alcohol and phenol in acetic anhydride.

 

Application of nanoparticles in targeted delivery and controlled drug release is recently highly attracted especially in cancer therapy. In this study with the aim of developing a novel drug vector based on metallic nanoparticles, gold nanoparticles with their unique characteristics were used to design a vector for targeted anti-cancer drug delivery to tumor. First, gold nanoparticles were chemically synthesized therough sodium citrate and sodium brohydrate reductions with average diameters of 22 and 11 nm, respectively. Then, the activated poly ethylene glycol (PEG) and activated folic acid were conjugated to the lysine-capped gold nanoparticles. Subsequently, the widely used anticancer... 

Wireless networks with the shared media require Medium Access Control (MAC) protocol that provides contention resolution mechanism. The design of MAC protocol is a challenging issue because of limited energy source and high propagation delay in UnderWater Acoustic Sensor Networks (UWASNs). The most important goal of the MAC design for underwater sensor networks is to resolve data packet collision efficiently with respect to energy consumption. So, selection of MAC protocol is an important task because it has significant impact on the system efficiency. A suitable MAC protocol must consider some factors such as fairness, energy consumption, latency and throughput based on various... 

One of the basic characteristics of Wireless Sensor Networks is their resource limitations. As a result, it is essential to try to decrease costs in such networks. These limitations are more critical in transmitting multimedia data with larger data units. In addition, when transmitting real-time multimedia data, delay is an important factor to consider. According to these limitations, Wireless Multimedia Sensor Networks are congestion prone. In this thesis, a transport layer protocol has been proposed. This protocol consists of three three steps in handling congestion. First, it detects congestion according to the queue length in the node. If the lsength is greater than a minimum threshold,... 

Swaying is an unfavorable phenomenon in moving suspended loads. So, cranes are usually equipped by anti-sway controllers. In this thesis, various controllers have been applied to a prototype of gantry crane system with various control inputs, and their competency has been assessed. First, a 2-DOF model has been introduced. This model contains a trolley and double pendulum with variable length attached to it. Then, it has verified by two approaches: first is comparing with simplified equations of model with flexible cable; and second is comparing with behavior of simulated system by Visual Nastran software. Next, a SISO linear controller has been designed for container cranes and applied to... 

Poly (vinyl alcohol) (PVA) hydrogel is a biocompatible material, which has been widely applied in drug delivery applications. Microspheres, nanospheres, and other types of particle-based drug delivery vehicles have proven capacity for long-term release. There is growing interest to overcoming the inherent pharmacological limitations of hydrogels by formulating particulate systems into the hydrogel matrix to form new delivery platforms. We here describe a simple composite system based on poly (vinyl alcohol) (PVA) hydrogels containing entrapped drug-loaded poly (lactic acid) (PLA) microspheres for controlled delivery over extended period of time. Gamma-Irradiation and freeze-thawing was... 

Smart wellsareunconventional wells with down-hole devices installed on their production tubing. Such wells allow us to continuouslymonitor flow rates, pressures, temperature and periodically adjust down-holevalves setting without any production intervention. This makes smart well technology to be considered as one of the most significantbreakthroughs in reservoir management technologies. So, modeling and simulating smart wellsautomated action represents a challenge in forecastingtheir performances.One of the easiest ways to model such wells is to transform theminto a multi-segment well with the ability tocontrol each segment independently. By using the commercial reservoir simulator,... 

Recent growth in wireless communications leads to higher demand for smaller and cheaper wireless products. This increasing demand for high speed wireless products and therefore development of new modulation techniques, results in higher sensitivity to phase deviations. This means that the voltage controlled oscillator or VCO circuit must has lower phase noise. VCO is an important part in Phase Lock Loop or PLL that has been used in most of transceivers. This thesis focuses on design of a Programmable VCO for DVB-H Application in 0.18um TSMC process. A VCO is an oscillator designed to be controlled in oscillation frequency by a voltage input. The frequency of oscillation is varied by the...