Sharif Digital Repository

Nowadays, a brain-computer interface (BCI) systems is considered as one of the necessary needs for individuals who are capable of doing their daily tasks. Despite of recent technological developments, such systems are not widely utilized. Spelling vocabularies and controlling wheelchairs are the most useful examples of using BCI. Todays, there has been a wide range of methods for establishing the connection between mind and computer. One of these methods is brain -Computer Interface Applications based on Steady State Visual Evoked Potentials (SSVEP). Although, these applications has a capability of fast responds and data transitions, only a few tasks can be given to the computer. In this... 

In this study, the effect of hydrophobic nanosilica (〖"FNS" 〗_"b" ), hydrophilic nanosilica (〖"FNS" 〗_"l" ), and both the physical (NS&ND) and chemical (NS@ND) hybrids of hydrophilic silica with nanodiamond on the properties of liquid silicone rubber (LSR) was examined. The structural analysis of hydrophilic and hydrophobic nanosilica using FTIR and TGA tests clearly demonstrates the differences between these two particles, with the main difference attributed to the presence of hydroxyl groups in the hydrophilic type. The results obtained from the tensile tests show that using 0.1% by weight of hydrophobic nanosilica and 0.1% by weight of the silica and diamond hybrid improves the mechanical... 

Today, heterocycle compounds have become increasingly important in organic chemistry syntheses. Many extracellular compounds have a confirmed biological property. Due to the high bioactivity of these compounds, the development of their synthetic methods has received considerable attention and numerous reports have been published on their synthesis. One of the most commonly used examples is terazosin. It was first marketed as a blood pressure lowering drug but was later used in the treatment of benign prostate gland.Another important class of these compounds may be the different derivatives of the pyrimidine molecule used in the treatment of cancer. The use of hetero- cyclic compounds is not... 

A series of innovative and efficient synthetic methods for the preparation of various derivatives of complex organic compounds have been introduced. These methods include one-step, multi-component, catalyzed ring-closing reactions, and kinetically controlled reactions, specifically designed for the synthesis of compounds with unique properties and potential medical applications. In these reactions, compounds such as rodanine-oxindole, dihydrospirocyclopentanebisoxindoles, thioxotiazolidine-indoline-2-ones, oxyindoline-carbamodithioate hybrids, and pyrrolo-pyrazol derivatives with oxindole structures and pharmaceutical potential have been synthesized. One of the prominent features of these... 

Airport saturation is one of the important issues which have always been of the specialists’ concern. One of the major applications of this subject is at the airport approach problems. While using current conventional approach procedures have many disadvantages regarding high fuel consumption and subsequent much environmental and noise pollution, the CDA concept which is one of the modern topics introduced in consequence of free flight theory, has less such disadvantages compared to conventional approach. Subject of this study is to investigate whether Procedural approach or CDA saturates an aiport sooner if the traffic flow increases. In this dissertation, using BADA database, CDA... 

The case of rapid small satellite aerial launch by mother airplane has various applications; such as space experiment, weather monitoring, and getting information from the earth monitoring during natural disasters. In this method, the satellite and the launch vehicle will be carried up by mother airplane to the definite height; then, the launch vehicle will be released and flied - to the insert of satellite into the desired orbit. Aerial launch system success depends on a set of complex elements and their interactions. In the present study, first of all, the element interactions will be investigated by system engineering approach based on operational scenarios; then, a new approach for... 

Various factors, such as increasing or decreasing the heat removal from the initial circuit, or increasing the flow rate of the cooling fluid in the reactor, causes the phenomenon of the coolant mixing in the PWR reactors. In this project, the thermohydraulic test of coolant mixing has been simulated in the pressure vessel of the Bushehr nuclear reactor. In this test, the mixing of the coolant caused by the reduction of heat removal from the primary circuit by the secondary circuit is investigated. In this case, the primary circuit temperature increases in the loop where the heat removal is reduced. The most important consequence of this event is the reactivity changes at the core of the... 

This study explores the trajectory optimization of two aircrafts’ formation flight seeking minimization of fuel consumption and flight duration while considering activation of the Traffic Collision Avoidance System (TCAS) during the flights. In order to model the effects of this system, a set of codes has been developed in the Matlab software environment, which utilizes an estimation model of induced drag for each aircraft by their relative positions. Also, position rotation is allowed, and the number and location of rotations are controllable by the user. The TCAS determines the allowable distances between aircrafts during flights based on relative velocities and relative heading angles.... 

In order to ensure the safety of the plants, a set of commissioning tests based on international standards for nuclear power plants is carried out before operation. In this research, one of the Bushehr power plant commissioning tests, the loop connection primary circuit cooling pump test, was simulated using the RELAP5 code. In this test, the effects of loop connection primary circuit pumps on the thermohydraulic parameters and the eneterance of test-related systems was evaluated. After simulating the systems related to the test and extracting the results of the stable state, were evaluated the transient results was obtained with the experimental results of the test of loop connection the... 

This work describes a methodology to enhance aircraft performance via proper mass distribution management. The methodology aims to limit aircraft configuration in early stages of the design process to its desired performance. Mass Distribution Management (MDM), that is used in this work, is a new mathematical model which predicts the so-called aircraft Handling Qualities (HQ) via proper positioning of aircraft mass. This work shows how proper changes in B-747-100 fuel tanks arrangement can enhance its flight quality up to level one during its entire cruise flight without use of any stability augmentation systems. In general this work introduce a methodology to examine different fuel tanks... 

Brain computer interfaces (BCI) are systems designed to understand the brain function from activation patterns and dynamics recorded from the brain activity and use this knowledge to give disabled people the ability to communicate with their surroundings. Features are extracted from recorded signals from the brain while occupied in a mental task and classified into categories related to the task given. These classifiers are then used for the estimation of user anticipation. Usually, the tasks defined are meant to evoke or induce a potential in the pattern of the brain. Awareness of error responses is one of the cognitive functions of the brain which occurs when a response is in conflict with... 

Airline scheduling is a dynamic process in nature such that it changes not only during one year period but also in smaller intervals due to the economic, political, religious, and social factors. Basically, airlines schedule planners through using mathematical models decide which flights are to be served in what periods of time and at what costs. This has to be done considering a set of constraints of different nature, from airspace and airport congestion up to climatic conditions or even crews working conditions. Such a complex problem requires different methods for an efficient solution. In this study by using network optimization method and applying different operational constraints on... 

LOOP accident is one of the most important accidents in NPPS and it leads to loss of power supply of the RCP pumps which are the main pumps of primary circuit. Subsequently trip of the rector occurs. In safety analysis, concerning worst conditions, assumes that after a small period of time, main generator of plant stops working and loss of AC power supply of all power plant loads including safety systems ocures. To control of this accident, it’s necessary to startup and load backup power supply system (EDGs) for at least one safety channels, if not, the accident moves forwards and becomes S.B.O accident which is more important accident that ends to core damage because of stops working of all... 

Towards basic-applied Research in the System Sciences fields, this Research has been to try to understand the behavior patterns and Functional Architecture of parasitic organisms and Use these in Social-Economic Systems. In this research four scenarios for parasite behavior were found and based on one of them, the recent "Financial Crisis in Greece" has been evaluated. The results show that the developed model, can be effective in similar conditions.
 

Identification of different hazards in a UF6 production process, and evaluation of the risk originated from these hazards is the main objective of this project. A number of hazards are present in a typical UF6 production process, such as leakage of chemical gases like HF and F2 and also radioactive UF6 gas release. In order to evaluate risk due to these hazards, probabilistic approach has been used. Due to lack of probabilistic safety criteria (PSC) for chemical releases, only for UF6 gas release risk assessment has been done. As a first step in PSA of this process eight groups of initiating events have been identified using HAZOP study, and for each initiating event, event tree analysis...