Sharif Digital Repository

In recent years, much attention has been paid to wind energy and the expansion of wind farms to replace fossil fuels with this energy source. Wind turbine blades are currently made of composite materials using thermoset matrices. These materials are not recyclable, and it is impossible to return their resins or fibers to the production cycle. In this research, an attempt has been made to replace thermoset resins with thermoplastic materials that can be recycled. In the following, manufacturing and performance aspects of thermoplastic resins have been examined, and the optimal material has been selected using the modified fuzzy logic method (MFLM). In this study, reactive processing of... 

The general and primary goal of this research was to identify the barriers to effective managerial coaching and their mechanisms of influence in an organization. With regard to deeper understanding of the context as the research progressed, the final goal of the study was to identify barriers to effective managerial coaching and their mechanism of influence when a manager faces employee’s undesirable performance, in a data center services unit. Managerial coaching is the manager’s practice of facilitating employee’s learning which improves the employee’s performance toward independent performance. The study was conducted in two main phases using grounded theory approach. Data was collected... 

In this research, we have presented a method to delay the propagation of fault current in high voltage power supplies. Common protection methods usually protect the load and do not protect the power supply itself well. In this research, our goal was to propose a method to prevent the short circuit fault current from reaching the power supply elements. At first, the available methods to limit the fault current and protect the high voltage power sources were studied and investigated. Then, using the transmission line theory, a ladder filter was designed as an alternative to the normal filter at the output of the power supply. In the next step, using software simulation, the performance of the... 

Constantly rising fossil fuel consumption and the resulting air pollutants have caused hybrid electric vehicles to be considered as the most efficient mid-term solution for decreasing problems resulting from environmental pollutions and rising fuel prices. Various types of hybrid electric vehicles and power transmission schemes are studied in this thesis. Electric motors utilized in electric vehicles and hybrid electric vehicles such as induction motor, brushless permanent magnet motor, DC motor and switched reluctance motors are investigated based on previous studies and researches, and are compared for all basic criteria. For completing the comparison procedure and selecting the most... 

A Tesla charged PFL Bipolar pulsed power generator has been successfully designed and simulated. The compact Tesla transformer that it employs has successfully charged capacitive loads to peak voltages up to 0.6 MV . The Tesla–driven PFL generator is capable of producing a voltage impulse approaching .3 MV with generating a peak electrical power of up to 1.8 GW for 5 ns when connected to a matched resistive load. Potentially for medical application, a bipolar former has been designed and successfully simulated as an extension to the system and to enable the generation of a sinusoid-like voltage impulse with a peak-to-peak value reaching 600 kV and having a frequency bandwidth beyond 1 GHz.... 

With the expansion of the use of electric energy, the importance of sustainable supply of this energy has been revealed. The task of supplying this energy is with power systems, therefore, for a stable supply of electrical energy, it is necessary to continuously monitor the systems. Power systems are composed of various destructible components such as cables. There are various methods and tests for maintaining and monitoring power cables. One of the daily maintenance methods of alternating current cables is called very low frequency testing. The main advantage of this test is the small and portable nature of the test equipment. In this thesis, the design of a very low frequency alternating... 

Gene regulatory modeling in different species is one of the main aims of Bioinformatics. Regarding the limitations of the data available and the perspectives which should be taken into account for modeling such networks, proposed methods up to now have not yet been successful in yielding a comprehensive model. In one of the recent researches, the Gene regulation process is considered as a nonlinear dynamic stochastic process and described by state space equations. Afterwards, in order for the unknown parameters to be estimated, Extended Kalman Filtering is used. In this thesis, first of all, Gene complexes are taken into consideration instead of genes and afterwards, Extended Kalman... 

Distal humerus fractures commonly take place in adults with low bone mineral density causing major technical challenges upon orthopedic surgeons. Persian fixation method was introduced as a novel technique to stabilize small fragments in comminuted distal humerus fractures using a set of K-wires and reconstruction plate. The objective of the present study is to measure the stiffness and stability of this technique and analyze the effect of influential parameters with numerical simulation and biomechanical testing on a cadaveric specimen. Furthermore, we were able to propose new method to model plastic deformation of implants in surgery.Validation of the finite element (FE) model was... 

Predicting the Amino Acids that have a catalytic effect in the enzymes, is a big step in appointing the activity of the enzymes and classifying them. This is a very challenging job, because an Amino Acid can appear in a variety of active sites.The biological activity of a protein usually depends on the existence of a small number of Amino Acids. Detecting these Amino Acids from the sequence of Amino Acids has many applications. Usually, the Amino Acids that are preserved are known as the Amino Acids that build up the active site, but the algorithms for finding the preserved Amino Acids are much more complex. There are a lot of algorithms for predicting the active sites of Amino Acids, but...