Sharif Digital Repository

People are increasingly using private vehicles as a result of the ever-increasing population growth worldwide and the increasing number of travel requests through the transportation network. There are many problems associated with the use of private vehicles on the transportation network, including traffic congestion and air pollution. To address the existing demand, decision-makers have always sought effective modes to respond to the existing situation. For passengers, the proposed modes of transportation should offer the same level of convenience and affordability as a private vehicle. In recent years, shared mobility has become increasingly popular. This mode of transportation has... 

Using superconducting synchronous machine leads to many advantages such as increasing overall efficiency, decreasing mass and valume of peropulsion system, eliminating some restrictions in hydrodynamic design , etc. The goal of this thesis is design of 200 kW, with 250 rpm superconducting synchronous motor for small ship propulsion drive application. The low speed motor can be directly coupled to the propeller whitch eliminates bulky and inefficient gearbox. After comparison of different structures of superconducting synchronous machines, finally rotating superconducting field with stationary copper armature winding is selected as the most approporiate structure for our application.
For... 

Hyderogels are hydrophilic polymers with three dimensional network structure, due to their high water absoption, their application to life and industry is increasing from day to day, such as tissue engineering, actuators and sensors, drug delivery and therapeutic treatment. In this project, it has been attempted to produce polyacrylamide/alginate double network hydrogels with the use of graphene oxide nanosheets to indicate that it is possible to combine toughness and self-healing in a hydrogel with the opposite nature of each other. To evaluate mechanical properties, uniaxial tensile test and loading-unloading test were used. The results indicate that increase the weight ratio of acrylamide... 

Most propulsion systems use nozzles to increase the velocity of exhaust gas. Therefore, the efficiency of nozzles is important. Losses due to geometry and physical phenomena inside the nozzle define this efficiency. The length and divergence angle of the nozzle, the throat diameter, the Reynolds number, and the specifications and the combinations of fuel have a direct impact on these losses. Solid propellant rockets are widely used and today optimization of rockets is most noticeable. On the other hand, in different phases of design and optimization, empirical experiments are necessary, which are costly in real dimensions. The use of laboratory motors with specific considerations decrease... 

Our body makes use of many degrees of freedom in muscle space. As a result, there are many solutions for activating muscles when performing a specific task. “how our central nervous system (CNS) controls abundant degrees of freedom?” has been a popular question for researchers in the field of motor control since Bernstein. The existence of muscle synergies is one of the proposed hypothesis, and there is experimental evidence that they are encoded in our CNS as building blocks. The aim of this study is to study the effect of training on the number, structures, and activation profiles of muscle synergies that are used for maintaining balance. For this purpose, electromyography data from 28... 

Reduction of power converters’ cost is one of the most important efforts to improve machines control systems. In this way, some new topologies for power electronic converters have been proposed. Among various topologies, four switch three phase inverter (FSTPI) thanks to the simple circuit, low cost, minimized conduction and switching losses and high reliability has attracted much attention recently. In this thesis, direct torque control (DTC) method is utilized to control of four switch inverter fed induction motor. In this way, in order to decrease flux and torque ripple and achieving constant switching frequency, a new Discrete Space Vector Modulation (DSVM) method have been proposed in... 

In systems possessing spatial or dynamical symmetry breaking, Brownian motion combined with unbiased external input signals, deterministic and random alike, can assist directed motion of particles at nanoscale. “Brownian motors” are devices by whi thermally or extrinsically activated processes are controlled and used to generate directed motion in space. Rectification devices involving asymmetric substrates are termed ratets and if the potential priodically turns on and off in time, it is called “Pulsated Ratet.“ In this resear net current of particles in 2D pulsated asymmetric potential landscapes is surveyed theoretically and by
Monte Carlo method simulation  

Nowadays the growing demand for energy, and, on the other hand, the limited resources of fossil consuming energy in the world have caused the energy operation and consumption management to be taken into consideration much more than the past. Based on this background, improving the efficiency of feed conversion technologies in supplying the energy demanded by the consumers is the foremost and the most crucial solution to preventing energy loss. Another approach to reducing the losses through energy generation and transmission is the use of distributed energy generation systems in small scale. The advantages of applying this type of technology are the possibility of installing near the load... 

In the present thesis, intracellular fluid flows have investigated for study cell motions. It is due to firmly relation between the cell motion and these flows. Generally, the cell firstly adheres to a surface, then, moves forward with the effects of the internal fluid flows. In this study, the cell structure is invided to two general parts; the front part of the cell and the cell body. The front part of the cell plays a essential roles in the cell motion, however, the cell body is considered as a extra cargo that is carried by the front of the cell. Therefor, in the present modellings, the front part is only considered. Here, using four different models for the front part of the cell, many... 

Mass production of Plug-in Hybrid Electric Vehicle (PHEV) and requests for long trip capability necessisated development of fast charging station that can charge PHEV in a feuling time of a conventional vehicle. Fast charging station design requires a systematic approach to consider various related issues.
The aim of this thesis is to design a fast charging station. First, the daly demand for PHEV charging is modeled considering number and type of PHEV as well as level and pattern of daily driving of PHEV. Uncertainty in daily driving and in PHEV state of charge in the start of charging are also considered in modeling charging demand. An approach, then, is proposed for optimal design of... 

Motor imagery causes Event related Synchronization/Desynchronization (ERS/ERD) in Electroencephalogram (EEG) signal. These potentials can be used as an input for a Brain Computer Interface (BCI) system. To do so, it is necessary for these inputs to be correctly classified. The quality of classification is severely affected by the features extracted. Common Spatial Patterns (CSP) algorithm is often used for this task. Some of this method disadvantages are neglecting non-stationary properties of EEG signal and its proneness to overfitting. Additionally, its success is highly dependent on the frequency band that the algorithm is performed in. The most suitable sub band is interchangeable... 

In the current era, the urgent need to reduce the use of fossil fuels and limit carbon emissions has highlighted the importance of shifting from traditional gasoline-powered vehicles to electric vehicles. The evolving landscape and challenges in the field of electric vehicles highlight the importance of ensuring the safety and reliability of energy storage systems. Lithium-ion batteries play a central role in electric vehicle technology, requiring thorough research efforts. Notably, the detection of internal short circuit, a common issue in lithium-ion batteries, has become a focus of researchers in recent years. This study aims to investigate the internal short circuit fault in lithium-ion... 

Video games, as a form of entertainment, have gained widespread attention and usage among all age groups, especially children and adolescents. With a wide variety of game genres and difficulty levels, they offer the opportunity to assess cognitive performance in individuals based on inter-individual differences and variable characteristics such as age, gender, and literacy level. The aim of this research is to study the brain response and gaze dynamics of individuals in a computer game (endless runner) based on electroencephalogram (EEG) signals and eye tracker data. The research process consists of two phases: "Brain Signal Processing in Motor Imagery Tasks" and "Reward and Punishment... 

converters, the different configurations for matrix converters are proposed. In this thesis, a one-phase to three-phase matrix converter is used to control in three-phase induction motor. Different control methods are proposed to control the induction motor. The novel control methods include close loop speed and converter output current controls of induction motor are proposed based on SPWM. The structure of indirect matrix converter for the mentioned application also investigated. Moreover, three usual method of control of induction motor: DTC (Direct Torque Control), FOC (Field Oriented Control) and Space Vector Modulation are applied to the single to three- phase matrix converter. Each of... 

Tehran, with approximately 750 km2 of land area, a population of more than 8 million people with about 4 million active on-road vehicles, is dealing with serious air pollution problems. To model the environmental phenomenon precisely, this study aims to develop on-road air pollutant emission factor matrices based on existing traffic in Tehran routes and to run air quality modelling within Tehran geographic boundaries. We developed emission factor matrices using SMOKES-MOVES emission modeling system. To do so, we calculated on-road emission factors from actual traffic-related data and run MOVES emission model. And use use them for different pollutants considered in air quality models. Then,... 

This thesis represents a comprehensive view of electric vehicles from the macroeconomic policy in the energy sector perspective. In fact, in this thesis all the efficient factors in the presence of electric vehicles in the transport sector have been completely proceed. Environmental, economic, social and political factors, power grids and infrastructure are considered as the impressive factors. In order to check all factors comprehensively, Systems thinking based on dynamic system method is used. The causal relationships between all the variables which are involved in the presence of electric vehicles and related models to this thesis are simulated in VENSIM software. To investigate this... 

The perpuse of this thesis is to design and fabricate a laboratory one degree of freedom stable platform under turbulences by model-based design method. To do this, different parts of the system were first modeled in the Solidworks software and then fabricated with various tools. With proper assembly of electronic and mechanical components, the original body of the system was created. Then, the controller motor with a stable platform which is attached to it was modeled and simulated in MATLAB software. Then, the parameters of the equations were calculated using standard identification tests and TCACS optimization algorithm. One of the challenges of this thesis is the malfunction of the... 

Pumps are widely used in oil and gas industry. Therefore condition monitoring for this type of equipment is very important. The motor current signature analysis (MCSA) technique as one of the condition monitoring techniques is very effective in the industry, but it is less used in industry. All conventional methods require additional sensors to be installed in the system; current signature analysis as a sensorless method can reduce the cost of condition monitoring. In this study, motor current signature analysis technique was used to diagnosis a centrifugal pump with a capacity of 187 kW from the refinery industry. The impeller wearing ring clearance problem has been investigated. This... 

Large penetration of electric vehicles and distributed generation (DG) resources in upcoming years will change the future vision of distribution networks from some passive load points into active ones. The imposed load of electric vehicles charging has caused many new challenges in operation and planning studies of distribution network. In contrast, the abilities of electric vehicles in feeding back power into the network (V2G programs) has attracted attention from grid operators and also vehicles owners. So, the problem of managing charging and discharging behaviors of electric vehicles has been introduced as a hot research topic in recent year. This dissertation as the first effort in this... 

In this project optimization of the assembly line balancing of Pride Motor is considered. The technical specification and limitizations as well as the production process of the product of this line is studied and documented through opc-fpc diagram, and assembly charts. Differential time study procedures are studied and the stop watch approach is selected to calculate the normal time of each operation. Through evaluation of line bottle necks the most important stations are reconsidered and have been pointed out.Considering operations procedure, priorities of the operations in the line, number of operations in each station, and requirements of investments for the changes, a solution for...