Loading...
Search for: faghihi--kamyar
0.11 seconds

    Three Dimensional Multi-Objective Terrain Following/Avoidance Optimization Using Heuristic Approach

    , M.Sc. Thesis Sharif University of Technology Kamyar, Reza (Author) ; Pourtakdoust, Hossein (Supervisor)
    Abstract
    Thus far, there has been a great attraction toward the optimal flight path planning problem. Terrain following/avoidance (TF/TA) flight is one of the most significant applications of this issue. To prevent from detection by the radars, fighter aircrafts, cruise missiles and helicopters often have to fly as close as possible to the surface during the operations. Such types of maneuvers are much more demanding and effortful than to be designed and implemented by human. The optimal TF/TA guidance system design comprises three phases: optimal path planning, closed-loop control system design for trajectory tracking and sensor blending to match the onboard and measured terrain data. So far, the... 

    Synthesis and Characterization of Cyclometalated Platinum Complexes Containing 2-Vinylpyridine Ligand

    , M.Sc. Thesis Sharif University of Technology Kamyar Khaledi, Niloufar (Author) ; Jamali, Sirous (Supervisor)
    Abstract
    The cyclometalated platinum(II) complex [Pt(Me)(bhq)(2-vpy)], 2, in which bhq = benzo{h}quinolone, 2-vpy = 2-vinylpyridine, has been prepared by reaction of the cyclometalated complex [Pt(Me) bhq)(SMe2)], 1 with one equiv 2-vinylpyridine. The similar complex [Pt(p-tolyl)(ppy)(2-vpy)], 3 in which ppy = 2-phenyl pyridine, has been prepared from reaction of the platinum(II) complex cis-[Pt(p-MeC6H4)2(SMe2)2] with one equiv 2-phenylpyridine and one equiv 2-vinylpyridine. Reaction of 2 with one equiv Br2 in acetone gave the cyclometalated platinum(IV) complex [Pt(bhq)Me(Br)(NC5H4CHCH2Br)], 4. The structure of the complexes 1-3 were determined using NMR Spectroscopy. The crystal structure of 3... 

    Direct conversion of inorganic complexes to platinum/thin oxide nanoparticles decorated on MOF-derived chromium oxide/nanoporous carbon composite as an efficient electrocatalyst for ethanol oxidation reaction

    , Article Journal of Colloid and Interface Science ; Volume 555 , 2019 , Pages 655-666 ; 00219797 (ISSN) Kamyar, N ; Rezaee, S ; Shahrokhian, S ; Amini, M. M ; Sharif University of Technology
    Academic Press Inc  2019
    Abstract
    In this work, we present the design and fabrication of a novel nanocomposite based on noble metal and metal oxide nanoparticles dispersed on highly porous carbon obtained via the pyrolysis of an inorganic complex and metal-organic frameworks. This nanocomposite is prepared by a two-step procedure: first, the composite support of nanoporous carbon (NPC) is obtained by the direct carbonization of the Cr-benzene dicarboxylic ligand (BDC) MOF in an Argon atmosphere at 500 °C (Cr2O3-NPC). A mixture containing Cr2O3-NPC and [PtCl(SnCl3)(SMe2)2] is then prepared, and underflow of Argon is heated to 380 °C. Finally, Pt-SnO2 nanoparticles are loaded on the Cr2O3-NPC support, and the obtained... 

    Optimal coupled spacecraft rendezvous and docking using multi-objective optimization

    , Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010 ; Volume 5 , July , 2010 , Pages 299-309 ; 9780791849194 (ISBN) Moradi, R ; Pourtakdoust, S. H ; Kamyar, R ; ASME Turkey Section ; Sharif University of Technology
    2010
    Abstract
    Spacecraft rendezvous and docking are two processes in which a chaser pursues and meets a leader spacecraft in order to perform several mission based tasks. Although in some preliminary design analysis, these two operations may be pursued independently there could be circumstances in which the spacecraft trajectory and attitudes are coupled and interdependent. The present study is based on the presumption that the often independent translational and rotational motions of the spacecraft are coupled as a result of thrust misalignment. So the thrusters not only contribute to the rendezvous translational motion, but also affect the docking reorientation maneuver through their disturbing effects.... 

    Combining multivariate image analysis with high-performance thin-layer chromatography for development of a reliable tool for saffron authentication and adulteration detection

    , Article Journal of Chromatography A ; Volume 1628 , 2020 Amirvaresi, A ; Rashidi, M ; Kamyar, M ; Amirahmadi, M ; Daraei, B ; Parastar, H ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    In this work, high-performance thin-layer chromatography (HPTLC) coupled with multivariate image analysis (MIA) is proposed as a fast and reliable tool for authentication and adulteration detection of Iranian saffron samples based on their HPTLC fingerprints. At first, the secondary metabolites of saffron were extracted using ultrasonic-assisted solvent extraction (UASE) which was optimized using central composite design (CCD). Next, the RGB coordinates of HPTLC images were used for estimation of saffron origin based on principal component analysis (PCA). The PCA scores plot showed that saffron samples were clustered into two clear-cut groups which was 92% matched with the geographical... 

    Systematic Planned (Preventive) Maintenance in Hospitals And Medical Centers of Iran

    , M.Sc. Thesis Sharif University of Technology Faghihi, Farshid (Author) ; Haji, Rasoul (Supervisor)
    Abstract
    Based on the latest statistical figures, more than 50 billion Rials worth of medical equipment exists in Iran’s medical centers. In spite of this, Breakdown maintenance is used in all hospitals, which means that the equipment is utilized as long as it is not out of order and only in such a situation, i.e. a breakdown, the necessary repair operation is conducted on the equipment. In fact, no maintenance is carried out to prevent a breakdown, while the “prevention from breakdown” concept has long been introduced in the majority of industries in many countries including Iran and its positive impacts are undisputable. This thesis aims at proposing a solution for the implementation of a “planned... 

    Properties of alumina nanoparticle-filled nitrile-butadiene-rubber/ phenolic-resin blend prepared by melt mixing

    , Article Polymer Composites ; Volume 30, Issue 9 , 2009 , Pages 1290-1298 ; 02728397 (ISSN) Faghihi, M ; Shojaei, A ; Sharif University of Technology
    2009
    Abstract
    Effect of alumina nanoparticle (ANP) on the properties of rubber compounds based on nitrile-butadiene-rub- ber (NBR) and NBR/phenolic-resin (PH) blend is examined. To investigate the surface characteristics of the nanoparticles on the performance of nanoalumina- filled compounds, trimethoxyvinylsilane (MVS) is attached chemically on the surface of ANP through an appropriate functionalization process. Various NBR and NBR/Ph compounds filled with ANP and functionalized ANP (f-ANP) are prepared via melt mixing using traditional open two-roll mill. Microscopic analysis carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveals good dispersion of... 

    Design and Fabriaction of a Power Amplifier and Its Linearizer Using Analog Predistortion Method

    , M.Sc. Thesis Sharif University of Technology Faghihi, Ehsan (Author) ; Banai, Ali (Supervisor)
    Abstract
    Modern communication systems,while demanding high power efficiency, suffer from the inherent nonlinearty effects. Such a problem becomes more critical in LEO satellites, in which there are fundamental power limitations. Considering that the main source of nonlinear effects are power amplifiers, one of the most common methods to improve signal quality in a transmitter, meanwhile maintaining power efficiency, is to utilize linearization techniques for power amplifiers. This project consists of two parts. The first is to design and fabricate a power amplifier for the desired frequency (2.4 GHz) and power requirements (3 W). The other is design and fabrication of a linearizer and matching it to... 

    Experimental Investigation of Mechanical Behavior of Structural Concrete with Combination of Waste Glass and Silica Fume

    , M.Sc. Thesis Sharif University of Technology Faghihi, Kamyar (Author) ; Khaloo, Ali Reza (Supervisor)
    Abstract
    Concrete is the second most structural material in the world. So attention and promotion of the concrete mix design with respect to variable issues and requirements, is very important. On the other hand, these days environment and its pollution has become very popular discussion. Waste-glass which is produced by human products is one of the environmental pollutants. In this thesis it replaces some aggregate in concrete and it can reduce the level of this material in the world. Also we study effects of silica-fume as cement replacement and properties enhancer in our concrete mix design and see how it can ... 

    An investigation on the structural characteristics and reinforcement of melt processed polyamide 66/multiwalled carbon nanotube composites

    , Article Polymers for Advanced Technologies ; Vol. 25, issue. 4 , 2014 , pp. 406-417 ; ISSN: 10427147 Shojaei, A ; Nourbakhsh, P ; Faghihi, M ; Sharif University of Technology
    2014
    Abstract
    Properties of melt processed polyamide 66 (PA66)/multiwalled carbon nanotube composite were first characterized experimentally. The experimental results exhibited the formation of crystalline layer around the nanotubes and a considerable enhancement in mechanical properties by incorporation of multiwalled carbon nanotube up to 1 wt%. Mechanical properties were analyzed in terms of structural parameters using micromechanical models proposed in this study. It was suggested that the mechanical properties were greatly dominated by crystalline layer and nanotube length. It was also deduced that the melt mixing process caused a significant nanotube breakage restricting further enhancement of... 

    Attitude Control of Flexible Satellite using CMG in Slew Maneuver Considering Bending and Torsion Deflections

    , M.Sc. Thesis Sharif University of Technology Faghihi Nia, Ali (Author) ; Asadian, Nima (Supervisor)
    Abstract
    In this thesis the attitude dynamics, simulation and control of a flexible satellite with CMG (Control Moment Gyro) actuator in three-dimensional slew and rest-to-rest maneuvers have been studied. The flexible satellite is modeled as a rigid hub and two flexible appendages. The bending and torsion of the flexible panels have been considered. The equations of motion have been derived using the Lagrange method and assumed-modes approach is utilized for converting the partial differential equations of structural dynamics into an ordinary differential equation set. The MATLAB and SIMULINK software has been used for simulation and validation of the equations of motion. The simulation and control... 

    Experimental and theoretical study on the mechanical properties of novolac phenolic resin nanocomposites: Effects of nanoclay and multiwallwed carbon nanotube

    , Article ECCM 2012 - Composites at Venice, Italy, Proceedings of the 15th European Conference on Composite Materials, 24 June 2012 through 28 June 2012 ; 2012 ; 9788888785332 (ISBN) Jahanmard, P ; Shojaei, A ; Faghihi, M ; Sharif University of Technology
    European Conference on Composite Materials, ECCM  2012
    Abstract
    The present work focused on the characterization of mechanical properties of novolac phenolic resin (PF) filled with two types of clays, including modified and unmodified ones, and multiwalled carbon nanotube (MWCNT). It was found that the solution mixing method is able to disperse the nanoparticles within the PF resin appropriately. It was also shown that the unmodified clay (Closite Na+) has the highest influence on the mechanical properties possibly due to the good level of dispersion as well as the good interfacial interaction. Theoretical analysis based on the rubber elasticity theory showed that the nanoparticles influence the evolution of crosslinking density and network structure  

    Characterization of polyamide 6/carbon nanotube composites prepared by melt mixing-effect of matrix molecular weight and structure

    , Article Composites Part B: Engineering ; Volume 78 , 2015 , Pages 50-64 ; 13598368 (ISSN) Faghihi, M ; Shojaei, A ; Bagheri, R ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    Effects of molecular weight and structure of polyamide 6 (PA6) on morphology and properties of PA6/MWCNT prepared by melt mixing were investigated. Microscopic analysis showed fine dispersion of MWCNT within low viscosity PA6s due to domination of melt infiltration into MWCNT agglomerate at low viscosity matrices with linear structure. Rheological data indicated good interfacial interaction with no percolation of MWCNT up to 2 wt% loading. DSC thermograms showed nucleating role of MWCNT on crystallization of PA6s with marginal effect on crystallinity. Experimental data supported with micromechanical model showed limited improvement on mechanical properties, but it was closely consistent with... 

    Nonlinear Vibration Analysis of Circular Microplate Based on Strain Gradient Theory

    , M.Sc. Thesis Sharif University of Technology Faghihi, Mohammad Amin (Author) ; Asghari, Mohsen (Supervisor)
    Abstract
    Nowadays the combination of mechanical and electronic systems in small scales is gaining attention. Micro electro-mechanical systems are widely used in various industries such as car manufacturing and electronic chips. In these devices, the most important and useful mechanical structures are beams and plates. Therefore, investigating the mechanical properties of these structures in very small scales (micro and nano) is of great importance. Decreasing the size to these scales leads to the dependence of the behavior of these structures to size. Accordingly, some theories for prediction of these behaviors have been presented, one of which is the strain gradient theory. This theory is used in... 

    Intelligent topology-oriented load shedding scheme in power systems

    , Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 652-656 ; 9781728115085 (ISBN) Zare, F ; Ranjbar, A ; Faghihi, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Load shedding is a prevalent emergency control designed to prevent system blackouts. The higher complexity and lower predictability of modern power systems makes it difficult to rely on conventional load shedding schemes which shed loads in pre-defined steps without sufficient consideration of the actual system characteristics and the disturbance situations. In case of large disturbances, the power system stability can be improved by optimal load shedding in more effective load buses. Proposed scheme utilizes improved Power Flow Tracing method to determine the amount and location of load drops considering power system constraints. Numerical simulations conducted on IEEE 39 bus standard test... 

    Intelligent topology-oriented LS scheme in power systems integrated with high wind power penetration

    , Article IET Generation, Transmission and Distribution ; Volume 14, Issue 9 , 2020 , Pages 1684-1693 Zare, F ; Ranjbar, A ; Faghihi, F ; Sharif University of Technology
    Institution of Engineering and Technology  2020
    Abstract
    Load shedding (LS) is one of the most important protection schemes to prevent system blackout. In the case of largedisturbances, optimal LS in appropriate buses can effectively maintain the system stability. The higher complexity and lowerpredictability of modern power systems with high wind power penetration make it difficult to rely on conventional LS schemes,which shed a fixed, predetermined amount of load regardless of disturbance location. This study presents an intelligent LSscheme based on synchrophasor measurements that are adapted to both disturbance size and power system inertia. Theproposed scheme utilises improved power flow tracing method to determine the amount and location of... 

    Effects of rubber curing ingredients and PhenolicResin on mechanical, thermal, and morphological characteristics of rubber/phenolic-resin blends

    , Article Journal of Applied Polymer Science ; Volume 108, Issue 6 , 2008 , Pages 3808-3821 ; 00218995 (ISSN) Derakhshandeh, B ; Shojaei, A ; Faghihi, M ; Sharif University of Technology
    2008
    Abstract
    This article examines the physical and mechanical characteristics of mixtures of two different synthetic rubbers, namely styrene-butadiene rubber (SBR) and nitril-butadiene rubber (NBR), with novolac type phenolicresin (PH). According to Taguchi experimental design method, it is shown that the addition of PH increases the crosslinking density of rubber phase probably due to its curative effects. Thermal analysis of the blends indicates that, contrary to NBR/PH blend, thermal stability of SBR/PH blend is dependent on sulfur content due to predominant polysulfidic crosslinks formed in SBR. Slight shift in glass-transition temperature (Tg) of pure SBR and NBR vulcanizates by the addition of PH... 

    Selection of adsorbents for different applications and processes: A review

    , Article Petroleum and Coal ; Volume 61, Issue 5 , 2019 , Pages 932-948 ; 13377027 (ISSN) Sadighi, S ; Sheikh Alivand, M ; Faghihi, M ; Sharif University of Technology
    Slovnaft VURUP a.s  2019
    Abstract
    Adsorption is one of the most sophisticated separation processes widely used in oil, gas and petrochemical facilities, and there is no doubt in the environmental and technological significant of this technology. But, the key to design an efficient adsorption service is to accurately select a suitable adsorbent that strongly dependent to the feed composition, product specification, and operating conditions. During the last 30 years, different classes of solid adsorbent have been manufactured; but, they should be meticulously chosen accordingly. In this paper, the specification and main charac-teristics of adsorbents generally used in oil, gas and petrochemical processes including activated... 

    Hybrid learning approach toward situation recognition and handling

    , Article Computer Journal ; Volume 65, Issue 5 , 2022 , Pages 1293-1305 ; 00104620 (ISSN) Rajaby Faghihi, H ; Fazli, M ; Habibi, J ; Sharif University of Technology
    Oxford University Press  2022
    Abstract
    We propose a novel hybrid learning approach to gain situation awareness in smart environments by introducing a new situation identifier that combines an expert system and a machine learning approach. Traditionally, expert systems and machine learning approaches have been widely used independently to detect ongoing situations as the main functionality in smart environments in various domains. Expert systems lack the functionality to adapt the system to each user and are expensive to design based on each setting. On the other hand, machine learning approaches fail in the challenge of cold start and making explainable decisions. Using both of these approaches enables the system to use user's... 

    Mechanical Properties of Al2O3-ZrO2 Nanocomposites Fabricated by Gelcasting

    , M.Sc. Thesis Sharif University of Technology Arvandi, Shahab (Author) ; Faghihi Sani, Mohammad Ali (Supervisor)
    Abstract
    Gelcasting is a new ceramic forming technique getting worldwide attention. The process is based on casting of slurry; containing powder, water and water-soluble organic monomers. The premix solution was prepared using Acrylamide as a monomer and Methylene bisacrylamide as a crosslinker with AM:MBAM ratio of 25:1, and Poly Acrylic Acid Sodium as a dispersant (1 wt% based on ceramic powders weight). A series of Al2O3/ZrO2 ceramic nanocomposites with 15, 17.5 and 20 wt% content of ZrO2 and 40, 43, 45, 47, 50, 53 and 55 vol.% of solid loading were fabricated by gelcasting. After casting the mixture, the monomer was polymerized to form gel parts. Drying, burning out and sintering completed the...