Sharif Digital Repository

There is many sources of uncertainty in the power plants such as continuous changes of the ambient temperature and the climate condition. The controller of the boiler-turbine unite should be robust against uncertainties and overcome the changes in the operating condition. In this regard, a robust adaptive variable structure control scheme (RAVCS) is proposed to control a nonlinear multi-input multi-output (MIMO) model of industrial boiler-turbine unite, in the presence of unknown parameters and bounded uncertainties as well as external disturbances. Moreover, a robust controller based on and in the presence of rational deviation in parameters, is designed. To investigate the zero... 

Air-handling unit (AHU) is one of the installations that is responsible to control the temperature and humidity inside a space using the heating, cooling, humidifier and drying air. At present, energy efficiency in building is an important issue to maintain the comfort conditions. One of the most common ways to optimize the performance of industrial installations is the use of control systems, which leads to the reduction in both of the costs and energy consumption. In this research, a multivariable nonlinear dynamic model of the AHU with one zone in the VAV (variable air volume) system for working in summer is considered. At first, introduction, limitations and driving the equations for the... 

Nowadays, oil has an important role in our life and most of its role can be seen on the transportation. Discovering and extraction of oil are very important to produce oil and receive it to costumer. When oil is discovered, the oil companies used to drill the ground to extract the oil but they can’t extract all of oil from its reservoir. So, researchers proposed to inject another fluid like water to the oil reservoir to extract oil. Oil is trapped in the porous media which has a lot of pores and some of them have a micro scale size and they contain oil. When water is injected to the reservoir it flows in this pore and interfaces with oil and they create a multiphase flow. The governing... 

One of the passive control systems that are used widely in today’s buildings are metallic yielding dampers. Metallic yielding dampers by absorbing earthquake input energy, prevent inelastic defromations form in beams and columns. In this research, the behavior of an innovated metallic yielding damper, named pistonic damper is investigated. This damper consists of a number of circular parallel plates with constant or variable thickness that dissipate seismic input energy by flexure yielding in small displacements. at large displacements stress field in plates is changed and this caused the stiffness and strength of damper are increased and show shell behavior. this kind of behavior... 

The main goal of this project is to design and implement an Endoscopic Sinus Surgery Simulator using a nonlinear model relating the force and displacement of the surgery tool interacting with the virtual sinus tissue. This model approximately matches the force-displacement data attained from the experiments conducted on the real sinus tissues. To simulate the behavior of the sinus tissue in a virtual environment, a haptic device is utilized which imitates the behavior of the surgery tool interacting with the tissue model. The haptic device in this project is a Falcon Robot. Because of the uncertainties in the parameters of the robot and the operator’s hand model (which is considered in the... 

No one bears thinking about undergoing a surgery by an unexpirienced surgeon, the consideration of which implies the prominence of effective surgical trainings. The advent of utilizing haptic interfaces as a novelty in this field has led to a more promising surgery education. These haptic interfaces consist of three communicating parts namely: operator’s hand, haptic robot, and tissue virtual environment. Design and implementation of a proper controller in order to stabilize the haptic interface during surgery simulation, with acceptable transparency, is still novel an otherwise challenging research field. In this thesis we consider an appropriate nonlinear model for both virtual tissue as... 

In this study, reform strategies to enhance private sector participation in infrastructure projects is provided. The study is presented in the form of words that government institutions could use in the highest level. the pattern used for this study is based on system thinking in which all components are in causal relationship with each other. It was made effort to policies and upstream objectives of the country be respected. To provide research content, content analysis of successful experiences in the world was done. Finally, obtained strategies was presented to the experts, reformed and important cases was investigated. Lack of information and difficult access to country's infrastructure... 

The research field of localization with high precision (precision of 10 micrometers) has greatly attracted attentions in recent years. Optical flow sensor is one of the inexpensive solutions for the localization of robot, which have been used in computer mice. The most important application of this thesis is to localize walking micro robot. The main challenge of previous research is the fact that sensor's precision is highly dependent on the surface texture. The aim of this research is to implement an appropriate algorithm on optical flow sensor in order to increase the robustness of sensor's precision to surface texture. In this regard, firstly experimental hardware has been designed and... 

Nowadays, the developments in control and robotics provide rehabilitation and power augmentation applications for the exoskeleton robots. In the rehabilitation applications, the goal is to help elderly and persons with paraplegia to do their daily activities and movements. One of this applications is to help these individuals for postural stability and recovering balance after receiving perturbations. In this research, we propose a control strategy for a lower limb exoskeleton to help the wearer to recover balance after a perturbation without using crutches. Here, we concentrate on the stance phase when a push is exerted to the robot and try to make the system quite upright. Therefore, a... 

In earthquake-prone communities, the post-earthquake functionality of hospitals is crucial. Hospitals can dramatically reduce earthquake casualties if they can remain functional and retain service continuity. A variety of earthquake-induced problems such as damage to hospital components, unavailability of medical staff, disruption in medicine supply, and failure of supporting infrastructure systems can negatively affect the functionality of a hospital. Hospital administrators and facility managers require appropriate tools to assess the effect of these problems on hospital functionality. This research presents a probabilistic framework to assess the functionality of hospitals following... 

FIDIC as a proposed model for a contract and including patterns of regular international contract projects. In Iran, many giant construction projects such as petroleum projects, power plants, roads and water networks was signed based on FIDIC contract pattern and These projects have been faced with many challenges .The main challenges for this contract are not ready. Improper translation of the original, traditional look owners to contractors, FIDIC modern approach depends on the project parties (owner - Consulting - contractors), Iran's judicial laws, lack of private land ownership and the absence of allocated budget that indicates the appropriate use of this model contracts in Iran. To... 

Oil and natural gas today are one of the most important sources of human energy supply, so that crude oil Percentage and natural gas provide 25% of the world's energy. Until now, vertical drilling methods have been used to extract oil and gas. In recent years, due to vertical drilling constraints, for extraction and access to places that can not be achieved by vertical drilling, Horizontal drilling has been increased. In horizontal drilling, a variety of vibrations including longitudinal, torsional, and lateral take place. These vibrations, if not controlled, can damage the equipment and the drilling field, as well as reduce the efficiency of the drilling process and increase the process... 

Infrastructure systems play a critical role in the economic and social activities of a community. Effective and continuous performance of these infrastructure systems is essential to the welfare and prosperity of the communities. Infrastructure systems comprise networks of interdependent assets that are built through a long and costly process. These assets are subject to a variety of factors that reduce the performance and reliability over time. These factors also increase the vulnerability of infrastructure assets in face of future probable hazards. In order to ensure the continuous and uninterrupted performance of infrastructure assets in post-hazard situations, asset managers should plan... 

Through the last decades, due to environmental issues and to confine CO2 emission and also dependency to the fossil fuels, renewable energy resources has been developed. It’s been expected up to 2035, the renewable energy resources will be scaled three times and among those resources, the wind energy will stand prominently. Out of this king of renewable resource, the horizontal wind turbine has been subjected in this research. The focus of is to design the controller in third of a 2 MW turbine operation by which stable rotor speed and nominal output power to be attained. Besides, to enhance the accuracy of the wind turbine profiles, the TURBSIM software (At the National Renewable Energy... 

Through the last decades, due to environmental issues and to confine CO2 emission and also dependency to the fossil fuels, renewable energy resources has been developed. It’s been expected up to 2035, the renewable energy resources will be scaled three times and among those resources, the wind energy will stand prominently. Out of this king of renewable resource, the horizontal wind turbine has been subjected in this research.The focus of is to design the controller in third of a 2 MW turbine operation by which stable rotor speed and nominal output power to be attained. Besides, to enhance the accuracy of the windturbine profiles, the TURBSIM software (At the National Renewable Energy... 

The development of the methods to evaluate the seismic resilience of communities, infrastructures, and structures has attracted many researches. To estimate the resilience with accuracy, developing a model that can simulate the events during the recovery time is very important. For the same, modelling the aftershocks with their accumulative effects on the damaged buildings during the recovery time has been the main focus of the current study. The proposed approach to simulate the aftershocks’ effect utilizes the Monte-Carlo sampling, in which each sample includes the two following steps. The first step is the simulation of the cumulative damage caused by the mainshock-aftershocks sequence... 

Wearable robots, or exoskeletons, are electromechanical devices that aim to assist user by supplying additional mechanical power as needed. The interaction of these robots with humans and the possibility of robots using their various abilities such as intelligence, control power, sensors, etc., make one of the crucial components of these control algorithms, its interaction and integration with the user. In this regard, functional electrical stimulation is one way to use human abilities to control the robot and achieve broader goals. Adding functional electrical stimulation to a wearable robot creates an emerging group of robots called hybrid exoskeletons. Hybrid exoskeletons provide the... 

Oil pollutants are among the important sources of pollution in countries with oil and gas industries such as Iran. Soil pollution by these pollutants is one of the environmental issues and hazards. All kinds of organic and inorganic pollutants in the soil may penetrate the underground water or enter the atmosphere in the form of gas, which respectively enters the food chain through absorption by plants or enter the body of living organisms through breathing. They include humans, which are a threat to the health and life of living beings. For example, many of these pollutions cause diseases such as cancer, suppression of the body's immune system, or even obesity; therefore, it is necessary to...