Calculation of effective pair potential via the volumetric data

, Article Phase Transitions ; Vol. 87, issue. 1 , 2014 , pp. 38-58 ; ISSN: 01411594 Namdari, F ; Parsafar, G ; Sharif University of Technology

2014

Abstract

The concept of effective pair potential (EPP), in which medium effects and contribution of long-range interactions are added to near-neighbor pair interactions, is a useful tool to derive and calculate the thermodynamic quantities. It has been shown that the extended Lennard-Jones (12, 6, 3) potential is an accurate EPP for many systems. However, the parameters of this EPP are not known for any systems. We introduce a new approach to use experimental pvT data of a fluid to calculate its EPP parameters. Such calculation has been carried out for some fluids at some temperatures. Unlike the isolated pair potential, it has been shown that the parameters significantly vary with temperature. We...

Calculation of Effective Pair Potential Function by Using Pressure−Temperature−Volume Data

, M.Sc. Thesis Sharif University of Technology Namdari, Fatemeh (Author) ; Parsafar, Gholamabbas (Supervisor)

Abstract

In this work, by considering the medium effects and adding the long−range interactions to the isolated pair potential, the concept of the extended effective pair potential of the Lennard−Jones (12, 6, 3) has been purposed for dense systems. Due to lack of any information regarding the parameters of this potential for any fluid, the purpose of this work is to introduce a new method to calculate these parameters using experimental pVT data. Since the extended potential of Lennard− Jones (12, 6, 3) is a general function based on which that an equation of state can be derived (equation of state III) predicts many properties of dense systems that no deviation is observed. Also it doesn’t have...

Recent advances in silicon nanowire biosensors: Synthesis methods, properties, and applications

, Article Nanoscale Research Letters ; Volume 11, Issue 1 , 2016 ; 19317573 (ISSN) Namdari, P ; Daraee, H ; Eatemadi, A ; Sharif University of Technology

Springer New York LLC 2016

Abstract

The application of silicon nanowire (SiNW) biosensor as a subtle, label-free, and electrical tool has been extensively demonstrated by several researchers over the past few decades. Human ability to delicately fabricate and control its chemical configuration, morphology, and arrangement either separately or in combination with other materials as lead to the development of a nanomaterial with specific and efficient electronic and catalytic properties useful in the fields of biological sciences and renewable energy. This review illuminates on the various synthetic methods of SiNW, with its optical and electrical properties that make them one of the most applicable nanomaterials in the field of...

Synthesis, properties and biomedical applications of carbon-based quantum dots: an updated review

, Article Biomedicine and Pharmacotherapy ; Volume 87 , 2017 , Pages 209-222 ; 07533322 (ISSN) Namdari, P ; Negahdari, B ; Eatemadi, A ; Sharif University of Technology

Elsevier Masson SAS 2017

Abstract

Carbon-based quantum dots (CQDs) are a newly developed class of carbon nano-materials that have attracted much interest and attention as promising competitors to already available semiconductor quantum dots owing to their un-comparable and unique properties. In addition, controllability of CQDs unique physiochemical properties is as a result of their surface passivation and functionalization. This is an update article (between 2013 and 2016) on the recent progress, characteristics and synthesis methods of CQDs and different advantages in varieties of applications. © 2017 Elsevier Masson SAS

Robust composite nonlinear feedback control for spacecraft rendezvous systems under parameter uncertainty, external disturbance, and input saturation

, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; 2018 ; 09544100 (ISSN) Namdari, H ; Allahverdizadeh, F ; Sharifi, A ; Sharif University of Technology

SAGE Publications Ltd 2018

Abstract

This paper presents a new robust composite nonlinear feedback control law for accurate, smooth, and fast regulation in the presence of parameter uncertainties, external disturbances, and input saturation for a class of spacecraft rendezvous systems. The novel proposed method consists of the original composite nonlinear feedback part for good transient performance plus a nonlinear disturbance rejection part for reducing the steady-state error stemming from variable disturbances and simultaneously producing feasible control input. The nonlinear disturbance rejection relies on sliding-mode observer for disturbance estimation. Closed-loop system stability has been proved with the Lyapunov...

Robust composite nonlinear feedback control for spacecraft rendezvous systems under parameter uncertainty, external disturbance, and input saturation

, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 234, Issue 2 , 2020 , Pages 143-155 Namdari, H ; Allahverdizadeh, F ; Sharifi, A ; Sharif University of Technology

SAGE Publications Ltd 2020

Abstract

This paper presents a new robust composite nonlinear feedback control law for accurate, smooth, and fast regulation in the presence of parameter uncertainties, external disturbances, and input saturation for a class of spacecraft rendezvous systems. The novel proposed method consists of the original composite nonlinear feedback part for good transient performance plus a nonlinear disturbance rejection part for reducing the steady-state error stemming from variable disturbances and simultaneously producing feasible control input. The nonlinear disturbance rejection relies on sliding-mode observer for disturbance estimation. Closed-loop system stability has been proved with the Lyapunov...

Utility of Cooperative Parafoils for Recovery of Multi-Segmented Launch Systems

, M.Sc. Thesis Sharif University of Technology Namdari, Hassan (Author) ; Fathi Jegarkandi, Mohsen (Supervisor)

Abstract

Today, a lot of efforts have been done in order to commercialize space travels. Spacecrafts have a lot of components and producing each of them spends high costs. Components such as propellant tanks and boosters are multi segment and are released simultaneously and therefore it is economically feasible to recover them. Due to Parafoil ability in low-cost, soft (no damage to the cargo) and accurate landing, it is gradually replacing parachute. Parafoil can fly long distances after being released, so its landing point could be determined. The aim of the study is to evaluate this scenario in which some segments of launch vehicle (e.g. booster) that are equipped with Parafoil expand their...

Chemical Composition and Source Tracers of PM2.5 in Tehran

, M.Sc. Thesis Sharif University of Technology Namdari Ghale, Dariush (Author) ; Arhami, Mohammad (Supervisor)

Abstract

The PM2.5 particles are considered as one the most important pollutants of Tehran’s air due to their undesirable effect on health and environment. The particular matters which are in Tehran’s air are distributed from different sources. Because of lack of sufficient data about amount and chemical compounds of such matters in different areas, this study considers only concentration of particular matter and their composing elements in Sharif University, Tehransar, Mahalati, and Shahriyar station. By use of field measuring between 2015 to 2016 mass concentration of PM2.5 pollutant was calculated and then with the help of IC, GC/MS, and ICP chemical analysis which were conducted in University of...

Structural Design of a Launch Vehicle with Reusable First Stage

, M.Sc. Thesis Sharif University of Technology Hassan Jamaklu (Author) ; Haddadpour, Hassan (Supervisor)

Abstract

Aerodynamics loads and aeroheating during reentry, are one of the challenging issues in designing One of the main challenges in the design and application of reusable spacecrafts is the aerodynamic and thermal loads acting on their structures during reentry into the atmosphere. For this reason, all the concepts/prototypes presented in the 20th century were either not fully reusable, or were partially canceled, or did not have economic justification. In this report, the aerodynamic loads on the first stage of a launch vehicle during the launch and return phases have been investigated. Due to the fact that the main part of the first stage of the vehicle includes fuel and oxidizer tanks, the...

Optimal Trajectory Correction for Hazardous Near-Earth Asteroids

, M.Sc. Thesis Sharif University of Technology Farsi, Salman (Author) ; Zohoor, Hassan (Supervisor) ; Sayyadi, Hassan (Supervisor)

Abstract

The collision of moderately large asteroids and comets also referred to as Near-Earth Objects (NEO's) with earth would have catastrophic consequences. Such events have occurred in the past and may occur again in the future. However, for the first time in known history, humanity may have the technology required to counter this threat. Methods studied for mitigation of this hazard are based on deflecting asteroid's trajectory and are normally divided into two basic categories: high energy impulsive methods, and long-duration low-thrust methods. Two parts of mission to be optimized are the trajectory of spacecraft to reach the target and the deflection strategy which could be analyzed by the...

A revised version of ACO for cutting stock problem [electronic resource]

, Article International Journal of Industrial Engineering ; Vol 15, No 4 (2008), Pages 341-348 Eshghi, K. (Kourosh) ; Javanshir, Hassan ; Sharif University of Technology

Abstract

The one-dimensional cutting stock problem has many applications in industries and during the past few years has been one of the centers of attention among the researchers in the field of applied operations research. In this paper, a revised version of Ant Colony Optimization (ACO) technique is presented to solve this problem. This paper is a sequel to the previous ACO algorithm presented by the authors. In this algorithm, according to some probabilistic rules, artificial ants will select cutting patterns and generate a feasible solution. Computational results show the high efficiency and accuracy of the proposed algorithm for solving one- dimensional cutting stock problem

Control of Car-Like Multi Robots for Following and Hunting of Moving Target

, M.Sc. Thesis Sharif University of Technology Kouhi Gilvan, Hamed (Author) ; Sayyaadi, Hassan (Supervisor) ; Salarieh, Hassan (Co-Advisor)

Abstract

The main purpose of the present thesis is to establish a decentralized controller for some car–like multi robots to follow and hunt moving targets. Robots are very similar to actual cars considering geometric dimensions, mass and moment of inertia and so on; and outputs of the controller are steering-wheel and driving-wheel torques appropriately. Dynamics of the moving target is so that it escapes from the robots. Robots are equipped with antenna for getting wireless sensory signals, including range and bearing sensors. Kalman filter is used for estimation the target relative position and speed and robots state variables. The controller is designed for doing the above mentioned group...

Stock Price Forecasting Using Neural Networks and Fuzzy Logic

, M.Sc. Thesis Sharif University of Technology Alizadeh, Parisa (Author) ; Shavandi, Hassan (Supervisor)

Abstract

This research proposes a novel hybrid method for stock price index forecasting relying on technical analysis, the fundamental analysis of capital market, neural networks technology, and fuzzy logic. The new method shows a good performance comparing complicated and time-consuming forecasting methods. Several factors influence stock price; for example, an important one is the previous trend of stock price. Fortunately, by developing technical analysis and introducing the various indices of this method the maximum use of historical data is made in order to forecast future prices. Another kind of factors is macro-economic variables that their influence on the long-term trends of the stock...

Control of a Group of Mobile Manipulators for Cooperative object Transportation

, M.Sc. Thesis Sharif University of Technology Babaee, Mohammad (Author) ; Sayyadi, Hassan (Supervisor)

Abstract

In this thesis control of wheeled mobile manipulators for cooperative object transportation is investigated. Full dynamic model of a mobile manipulator with a three wheeled mobile base and a three DOF manipulator is derived using Gibbs-Appell method. Input-output linearization technique is used to control individual robots. Transporting the object is divided into two steps, first robots use a decentralized behavior-based method to approach and surround the object. Then virtual structure method is used to control the robots to transport the object cooperatively. Simulation results with three robots handling an object are presented to show the effectiveness of proposed method

Dynamic and Control of Tethered Satellite Systems

, M.Sc. Thesis Sharif University of Technology Yousefian, Peyman (Author) ; Salarieh, Hassan (Supervisor)

Abstract

In this work dynamic behavior of a two body TSS with main satellite as rigid body is studied and effects of tether elasticity and tension on the satellite dynamic are indicated in station keeping phase and circular orbit. Also a simplified modeling is introduced which could be used in nonlinear controller design. Lagrange and extended Lagrange method is used to derive equations of motion. It is shown that longitudinal vibration of tether has small effect on satellite attitude and angular velocity and because of high frequency it can be decoupled from satellite dynamic. In the simplified model, orbital motion is decoupled from equations of TSS and main satellite dynamic. Effect of decoupling...

Analysis of Control of Nonlinear Switched Systems

, M.Sc. Thesis Sharif University of Technology Toorani, Amin (Author) ; Zohoor, Hassan (Supervisor)

Abstract

Separate analysis of modern systems by continuous or discrete theories is not possible, because they cannot solely express the detailed descriptions of a system. As a result of this, researchers are motivated to study hybrid systems. Specific class of hybrid systems which consists of several continuous subsystems and a rule that specifies how to switch between them, is called a switched system. Recently, many studies have been done on the stability and control of switched systems. In this regard, the goal of present study is presenting applications of switched systems using two control methods. The first application is control of a chemical reactor system with multiple modes. We presented...

Design and Analysis of a Cable Based Robot Similar to a Human Hand

, M.Sc. Thesis Sharif University of Technology Abyaneh, Soroush (Author) ; Zohoor, Hassan (Supervisor)

Abstract

The application of manipulators is becoming more and more popular in objects handling especially when it is desired to have access to remote areas in destructive or hazardous taskspaces. For this purpose, a hand-like mechanism must be designed to be used as an end-effector, which can grasp objects. In this paper a cable driven grasping mechanism has been presented. In the proposed mechanism each finger consists of three phalanxes which are actuated by a single motor. Also, locking and unlocking constraints are used in the mechanism in order to generate an anthropomorphic motion, in which, the order of reaching phalanxes to the object is sequential, in such a way that each phalanx starts...

Data Integration with Multiple Ontologies in Semantic Sensor Web

, M.Sc. Thesis Sharif University of Technology Sadeghi, Shahrouz (Author) ; Abolhassani, Hassan (Supervisor)

Abstract

Sensor Observation Service (SOS) which is defined by Open Geospatial Consortium (OGC) Sensor Web Enablement group is a Web service specification in order to standardize the way sensors and sensor data are discovered and accessed on the Sensor Web. Multiple instances of this service can be implemented around the world, providing huge amount of data every moment. Each of these services operates in specific domain of knowledge (thematic), spatial and temporal dimensions. One way to reveal the underlying data over all of them is to provide an architecture for data integration to allow the user to query sensor data without the knowledge of the infrastructure components. In this research, a novel...

Crack Detection on Rotary Elements Using Vibration Analysis

, M.Sc. Thesis Sharif University of Technology Ari, Mostafa (Author) ; Sayyaddi, Hassan (Supervisor)

Abstract

Rotating machinery are found in most industrial units, that are highly susceptible to transverse cross sectional cracks due to fatigue. The vibration pattern of a rotor system reflects the mechanical parameter changes in the system. These vibrations can be used for identifying the cracks and appropriate actions can be taken to prevent more damage to the system. The dynamic behavior of cracked rotor is a subject of considerable current interest. Several researchers have developed models of cracked rotor systems. Therefore, In this thesis, the influence of the presence of transverse cracks in a simple Jeffcott rotor is analyzed. In first, on the basis of fracture mechanics, the direct and...

Positioning, Tracking and Shape Control in Micro-Beams Via Electrostatic Actuators and Incomplete State Feedback

, M.Sc. Thesis Sharif University of Technology Karami, Farzad (Author) ; Salarieh, Hassan (Supervisor)

Abstract

Systems that are electrostatically actuated have found a vast role in MEMS application. This technology is used in optical systems, sensors, micro switches, and deformable mirrors. Raising the use of these systems in fields that needs better performance highlighted the need to accurate study of dynamics and control of electrostatic actuated systems in micro scale. This work is dedicated to design of an estimation and control system for a micro-beam that is actuated by electrostatic. After a comprehensive survey on pervious works that are done on dynamic, applications, fabrication and control of these systems dynamic of the system is fully derived. The environmental factors like fringing...