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Energy and the wealth of nations : an introduction to biophysical economics
, Book ; Klitgaard, Kent
Springer International Publishing AG
2018
Optimization of Enriching Cascades Using Genetic Algorithms
, M.Sc. Thesis Sharif University of Technology ; Otukesh, Mohammad (Supervisor) ; Norouzi, Ali (Supervisor) ; Ayoubzadeh, Mohsen (Co-Advisor)
Abstract
One of the challenging issues in Iran's nuclear talks and Group 5+1 countries is the amount of Iran's enrichment capacity and the number of centrifuges needed to meet this demand. In this regard, Iran has recently announced that the basis for determining its enrichment capacity is the supply of fuel for the Bushehr power plant.Modeling and optimizing of gas centrifuge cascade is one of the most important problems in fuel cycle and isotope separation fields. To achieve this goal it is needed to comprehend of single centrifuge operation. Knowing the effectofsingle centrifuge parameters, it is easy to design a desired cascade. Minimizing the number of machines in the cascade is an anticipated...
Study on the Mass Transfer and Isotope Separation Phenomena in a Gas Centrifuge by Using FEREON Mixtures as Model Compounds
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Karimi-Sabet, Javad (Supervisor) ; Norouzi, Ali (Co-Advisor)
Abstract
In the nuclear industry, gas centrifuges are considered of high importance for the purpose of uranium enrichment. Today, with advances in science and technology, the use of gas centrifuges for separating isotopes other than uranium, is so common. With respect to the use of conventional methods such as Pancake equation in calculating the velocity profile in centrifuges, it is needed that A^2=(MV^2)/2RT≫1 (M: Feed molecular weight; V: Peripheral speed of centrifuge; T: Mean temperature of feed; R: The universal constant of gases). While the molecular weight of the feed mixture gets lower, the A2 parameter gets closer to one. So, other methods for modeling the behavior of the gas in the...
Boundary Layer Control of an Incompressible Turbulent Flow over an Airfoil, Using Quasi-spherical Surface Structures
, M.Sc. Thesis Sharif University of Technology ; Javadi, Khodayar (Supervisor) ; Taeibi Rahni, Mohammad (Supervisor)
Abstract
Boundary layer control has long been and still is considered to reduce drag. In this research, the effect of quasi-spherical structures on the control of boundary layer is investigated. First, flow over a NACA0015 airfoil was investigated. Then, flow over the same airfoil with quasi-spherical bumps on its upper surface was numerically simulated and the result of these two situations were compared. The dimensions and numbers of the bumps in longitudinal and lateral directions (different case studies) were chosen using trial and error. The three-dimensional, incompressible, and turbulent flow governing equations were numerically solved, using FVM and the OpenFOAM software. To get preliminary...
Analyzing Airport Saturation Based on Continuous Descent Approach
, M.Sc. Thesis Sharif University of Technology ; Malaek, Mohamad Bagher (Supervisor)
Abstract
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...
Sustainable Analysis of Unions Uses Axiomatic Design Theory with Focus on European Union
, M.Sc. Thesis Sharif University of Technology ; Malaek, S. M (Supervisor)
Abstract
In this project, we examine the stability or sustainability issue in unions, in other words we want to know whether integration in European Union is stable? Countries have positive attitude toward unions and being member in unions is at special priorities. The main reason for countires is improve economy and national Security.
The main question in this research is modeling European Union with Axiomatic Design Theory and analysis of sustainability based on this theory. This study has attempted to push Axiomatic Design Theroy in the new field of Systems Engineering and also it gives a new and differnet approach to stability.
The main question in this research is modeling European Union with Axiomatic Design Theory and analysis of sustainability based on this theory. This study has attempted to push Axiomatic Design Theroy in the new field of Systems Engineering and also it gives a new and differnet approach to stability.
Intentionality and Mental Models
, M.Sc. Thesis Sharif University of Technology ; Azadegan, Ebrahim (Supervisor)
Abstract
One of the important issues in the philosophy of mind is the challange about the content of mental states, how the mind can refer to the world. To explain this special relationship that is not observed in the physical world, various mental models have been implemented, one of which is the connectionism model. Connectionist networks are based on the idea of biological neural networks, and the main concern of connectionism is modeling the brain and implementing human mind characteristics. The connectionist model was proposed by emphasizing the necessity of linking symbols with their original content and meaning. In this model, data representation is done in a holistic way and based on network...
Control of Continuous-Time Chaotic Systems by Minimizing the Entropy Function Constructed on Conditional Probability
, M.Sc. Thesis Sharif University of Technology ; Salarieh, Hassan (Supervisor)
Abstract
In this research, we explore a novel approach for controlling continuous-time chaotic systems with unknown equations and exclusively using one measurable state variable. In pursuit of this objective, the study unveils two efficient approaches: one tailored for autonomous systems and the other designed for systems with external excitation. In both approaches, our methodology centers on minimizing the conditional entropy which is derived based on the conditional probability distribution of the only observable state variable. Considering the numerical nature of entropy calculations in practical issues, we have employed the Poincare map to discretize the continuous-time system. In the following,...
Main System Investigation of Turbocharged Diesel Engine During Performance Upgrade
, M.Sc. Thesis Sharif University of Technology ; Hajilouy Benisi, Ali (Supervisor) ; Nouri Broujerdi, Ali (Supervisor)
Abstract
The internal combustion engine power is determined by the amount of fuel effectively burned inside the engine cylinders. On the other hand, the fuel consumption is proportional to the air mass that enters the cylinders in each cycle. Conventionally, incoming the engine inlet air is at ambient conditions. However, with higher air density, the engine power increases for the same dimensions, so-called turbocharging. Although the engine's structure remains unchanged, it may be necessary to adjust the main systems of the engine simultaneously. This research investigated maximizing the power of a turbocharged diesel engine based on upgrading the degree of turbocharging. For this purpose, the EM355...
Design and Implementation of a Collision Avoidance Module in Dynamic Environment with Deep Reinforcement Learning on Arash Social Robot
, M.Sc. Thesis Sharif University of Technology ; Meghdari, Ali (Supervisor) ; Taheri, Alireza (Supervisor) ; Soleymani, Mahdieh (Co-Supervisor)
Abstract
Nowadays, one of the challenges in social robotics is to navigate the robot in social environments with moving elements such as humans. The purpose of this study is to navigate the Arash 2 social robot in a dynamic environment autonomously without encountering moving obstacles (humans). The Arash 2 robot was first simulated in the Gazebo simulator environment in this research. The simultaneous location and mapping (SLAM) technique was implemented on the robot using a lidar sensor to obtain an environment map. Then, using the deep reinforcement learning approach, the neural network developed in the simulation environment was trained and implemented on the robot in the real environment. The...
Numerical Investigation of the Effects of Environmental Parameters on the Simulation of Spread of Fire in Grasslands
, M.Sc. Thesis Sharif University of Technology ; Farhanieh, Bijan (Supervisor) ; Afshin, Hossein (Co-Supervisor)
Abstract
Fire in Grasslands is one of the most dangerous natural disasters that is uncontrollable at the time of its occurrence and will continue until there is a fundamental change in the conditions of the fire. Fire in Grasslands due to the high density of vegetation can produce a large amount of heat energy in a short time and in a very large area, which alone can cause the spread of fire in Grasslands. Today, numerical studies of fire behaviour and propagation are given more attention than experimental studies due to their lower costs and limitations. In the present study, the numerical simulation of the fire spread with the influence of climate parameters such as humidity, rainfall during fire...
Feasibility Study and Design of Artificial Energy Island (in Persian Gulf Region)
, M.Sc. Thesis Sharif University of Technology ; Abbaspour Tehranifard, Majid (Supervisor)
Abstract
As it is obvious from the name of this study, the goal of doing this study is the feasibility study of southern shores of Iran for building an artificial energy island for and designing it. In this project by studying seven points coastwise of southern Iran and defining the criterions and scoring the points, the Chabahar was determined as the best place for erecting the artificial energy island. With respect to the environmental condition of the chosen point and modeling in software ANSYS, the structure of the artificial energy island has been studied and the type, geometric shape, area, trough, and the setting of the anchoring system has determined. As a result of these efforts, a hexagon...
Optimazing Tehran LDV Fleet Regarding Environmental and Economic Restrictions
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Vahid (Supervisor)
Abstract
Tehran is the most populated area in Iran and is one of the most densely populated cities in the world where almost 40 percent of all days have been classified as unhealthy for sensitive groups. According to emission inventory of Tehran over than 85 percent of emission are due to different types of vehicles. And light duty vehicles share more than 80 percent all vehicles and are responsible for most of carbon monoxide and nitrogen oxides emitted in Tehran atmosphere. In this study real emission factor of Hybrid Synergy vehicles which just have been introduced to Tehran fleet were tested under real conditions of streets. Data produced in this research have been combined with previous...
Design and Fabrication of Engineered Biomaterials for Tissue Engineering Applications such as Cardiovascular System
, M.Sc. Thesis Sharif University of Technology ; Shamlou, Amir (Supervisor)
Abstract
Cardiovascular diseases are the leading cause of death all over the world, even more common than cancers. The first reason of mortality in Iran according to statistics is the occlusion of coronary arteries. Unfortunately almost one third of patients doesn’t have enough blood vessels to be used in the bypass surgery and need artificial vessels. These artificial blood vessels with small diameters (less than 6 mm) will fail quickly. As a result there is an increasing demand for tissue engineered blood vessels which are capable of enduring high blood pressures. An artificial blood vessel should mimic both structure and mechanical properties of the real one. Blood vessels have layered structures,...
Deformation Analysis of Magnetic Elastomers using Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Naghdabadi, Reza (Supervisor) ; Sohrabpour, Saeed (Supervisor) ; Goudarzi, Taha (Co-Advisor)
Abstract
Magnetic elastomers are smart materials that consist of a combination of elastomeric matrix and magnetic particles. The mechanical and magnetic properties of this materials are changed by Applying an external magnetic field. The presence of an external magnetic field can cause these elastomers deform largely.Significant deformations of the magnetic elastomers, has made them suitable for a wide range of applications. The aim of this project is to solve the governing equations of magnetic elastomers with finite element method. Since there are no suitable models for the behavior of these elastomers in the commercial softwares, magnetic field module and solid mechanics module should be coupled...
Design and Fabrication of an Optimized Wake Equalizing Duct in Order to Improve Propulsion System Operation
, M.Sc. Thesis Sharif University of Technology ; Seif, Mohammad S (Supervisor) ; Rad, Manouchehr ($item.subfieldsMap.e)
Abstract
Special geometrical sections, known as “duct”, which can be installed on merchant vessels stern in order to improve propulsion system and propeller performance, today have evolved considerably. The force which produces by the propeller depends on efficiency of propulsion system. In the way of improving the efficiency of propulsion systems, by using these special geometrical sections, to much research have been done from the mid-twentieth century. The Wake Equalizing Ducts (WEDs) in addition to conduct the more uniform fluid flow to the propeller disk (which causes to improve the propeller operation), affect on flow separation in ship stern zone and will decrease the separated flow zone....
Design, Fabrication and Model-base Control of a Brachiation Robot with Flexible Support
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Gholamreza (Supervisor) ; Namvar, Mehrzad (Supervisor)
Abstract
Nowadays, many researches are inspired by nature and living creatures in order to build various scientific and industrial products such as robots, because of the highest level of creativity which is used in creating them along with their high level of efficiency in power consumption and designing parameters. Underactuated Robots are the type of robots which have more degrees of freedom comparing to the number of operators. As a result their optimum control has a lot of complications. Brachiating robots are designed and built based on an inspiration from long armed apes (Gibbons). This type of monkey is highly skilled in twisting in trees and traversing. This type of movement benefits from...
Investigation, Design and Simulation of Elastography and IOTA Imaging Modes in Ultrasound Systems
, M.Sc. Thesis Sharif University of Technology ; Vosoughi Vahdat, Bijan (Supervisor) ; Kavehvash, Zahra (Supervisor)
Abstract
Ultrasound is one of the most widely used imaging techniques used by physicians and radiologists as a tool. It has many diagnostic and therapeutic uses. In particular, ultrasound imaging is used for prenatal imaging due to relative safety, low cost, nature Non-ionizing, instant display and ease of use by the operator, widely used in many countries around the world. According to the Ministry of Health, ovarian cancer is the most important cause of death in women The effect of cancer in Iran. Breast cancer is also one of the most common cancers in women, followed by cancer Cervix and ovarian and uterine cancers are also among the most common cancers in women. This issue is not only in Iran It...
Imaging Method To Detect Low Probability of Intercept Radars
, Ph.D. Dissertation Sharif University of Technology ; Nayebi, Mohammad Mahdi (Supervisor) ; Norouzi, Yaser (Co-Advisor)
Abstract
In this thesis, a new passive method suitable for Geolocating LPI radars is introduced. The method uses two Electronic Support (ES) receivers placed on a fast moving platform (e.g., an airplane or a satellite). The proposed method has a high processing gain, which makes it highly suitable for very weak LPI signals. The processing gain of the method was analytically derived and illustrated with simulation to determine if the proposed method can detect LPI radars in much lower SNRs compared to regular time-frequency LPI detection methods. Also, the resolution of the proposed method in both range and cross-range direction in radar location finding was analyzed. Furthurmore, the effect of the...