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    Processing and Characterization of Fracture Behavior of Hybrid Epoxy Nanocomposite Modified with Polycarbonate

    , M.Sc. Thesis Sharif University of Technology Amini NajafAbadi, Leila (Author) ; Bagheri, Reza (Supervisor)
    Abstract
    Epoxy resins have good mechanical and thermal properties, high chemical resistance and low shrinkage during cure but in spite of these good properties,they are brittle and this limits the usage of them. Adding a second, soft or rigid, phase has been always an effective strategy to improve the toughness of epoxy. Rigid phase used in resins are divided into organic and inorganic. The aim of this study is to increase epoxy toughness, maintaining mechanical properties and study effect of silica and polycarbonate on fracture toughness simultaneously. Mechanical properties including yield strength and elastic modulus are evaluated by pressure test. Additionally fracture toughness and three... 

    Secondary particles spectra in the decay of a polarized top quark with anomalous tWb couplings

    , Article Journal of Physics G: Nuclear and Particle Physics ; Volume 34, Issue 1 , 2007 ; 09543899 (ISSN) Mohammadi Najafabadi, M ; Sharif University of Technology
    2007
    Abstract
    An analytic expression for energy and angular dependence of a secondary charged lepton in the decay of a polarized top quark with anomalous tWb couplings in the presence of all anomalous couplings are derived. The angular distribution of the b-quark is derived as well. It is presented that the charged lepton spin correlation coefficient is not very sensitive to the anomalous couplings. However, the b-quark spin correlation coefficient is sensitive to anomalous couplings and could be used as a powerful tool in the search for non-SM coupling. © 2007 IOP Publishing Ltd  

    Semileptonic decay of a polarized top quark in the noncommutative standard model

    , Article Physical Review D - Particles, Fields, Gravitation and Cosmology ; Volume 74, Issue 2 , 2006 ; 15507998 (ISSN) Mohammadi Najafabadi, M ; Sharif University of Technology
    2006
    Abstract
    In this paper we study the noncommutative effects to the lepton spectrum from the decay of a polarized top quark. It is shown that the lowest contribution comes from the quadratic terms of the noncommutative parameter. The deviations from the standard model are significant for small values of the noncommutative characteristic scale. However, the charged lepton spin correlation coefficient has a remarkable deviation from the standard model from very low values of the noncommutative characteristic scale to 1 TeV. © 2006 The American Physical Society  

    Complex Activity Recognition by Means of an IMU-Based Wearable System for the Purpose of PD Patients’ Rehabilitation

    , M.Sc. Thesis Sharif University of Technology Tahvilian, Ehsan (Author) ; Behzadipour, Saeed (Supervisor) ; Ali Beiglou, Leila (Co-Supervisor)
    Abstract
    Parkinson's is a disease caused by a disorder in the central nervous system of the body. There is no definite cure for this disease, but one of the ways to prevent the progress of this disease is to use movement therapy. One of the goals of designing wearable systems consisting of inertial sensors is to make it possible to perform this movement therapy from a distance. The purpose of the present study and research is to use the approach of simple and complex activities in order to increase the accuracy in the detection of activities and also to solve the problems of the previous system, with the help of creating the ability to detect complex meaningful activities for Parkinson's patients. In... 

    Model predictive control of blood sugar in patients with type-1 diabetes

    , Article Optimal Control Applications and Methods ; Volume 37, Issue 4 , 2016 , Pages 559-573 ; 01432087 (ISSN) Abedini Najafabadi, H ; Shahrokhi, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2016
    Abstract
    In this article, two adaptive model predictive controllers (AMPC) are applied to regulate the blood glucose in type 1 diabetic patients. The first controller is constructed based on a linear model, while the second one is designed by using a nonlinear Hammerstein model. The adaptive version of these control schemes is considered to make them more robust against model mismatches and external disturbances. The least squares method with forgetting factor is used to update the model parameters. For simulation study, two well-known mathematical models namely, Puckett and Hovorka which describe the dynamical behavior of patient's body have been selected. The performances and robustness of the... 

    Anomalous single top quark production at the LHC

    , Article Physica Scripta ; Volume 82, Issue 3 , 2010 ; 00318949 (ISSN) Najafabadi, M. M ; Pooya, G ; Sharif University of Technology
    2010
    Abstract
    The anomalous top quark interactions with gluon (tug, tcg) allow the production of single top quarks at the Large Hadron Collider (LHC). Using the angular distribution of the charged lepton from the W boson in the top decay, we show that with the data of 10 fb-1 of integrated luminosity and in the collisions with the center of mass energy of 14TeV, the anomalous up and charm quarks coupling parameters κu,c/Λ can be measured down to 0.005 and 0.007 TeV-1, respectively  

    Experimental and analytical study of telescopic lead yielding damper

    , Article Journal of Constructional Steel Research ; Volume 150 , 2018 , Pages 371-383 ; 0143974X (ISSN) Eskandari, M ; Pournamazian Najafabadi, E ; Sharif University of Technology
    2018
    Abstract
    In this study, a novel type of passive energy dissipation device called a Telescopic Lead Yielding Damper (TLYD) is proposed and analyzed. This device comprises co-axial steel cylinders and lead rings, such that these rings act as shear locks between the steel cylinders. TLYDs dissipate energy through the plastic shear deformation of lead metal. The telescopic mechanism used in TLYDs allows these small-sized dampers to tolerate large axial displacements with low fatigue. For each telescopic level, a yield plateau is added to the hysteresis behavior of TLYD devices. Each yield plateau resists a different performance level, namely design-based and maximum credible earthquakes. Seven... 

    Wireless electrochemical preparation of gradient nanoclusters consisting of copper(II), stearic acid and montmorillonite on a copper wire for headspace in-tube microextraction of chlorobenzenes

    , Article Microchimica Acta ; Volume 185, Issue 1 , 2018 ; 00263672 (ISSN) Enteshari Najafabadi, M ; Bagheri, H ; Sharif University of Technology
    Springer-Verlag Wien  2018
    Abstract
    This work introduces a new gradient fiber coating for microextraction of chlorobenzenes. Nanoclusters of organoclay-Cu(II) on a copper wire were fabricated by wireless electrofunctionalization. The resultant gradient coatings are more robust, and thermally and mechanically stable. Wireless electrofunctionalization was carried out in a bipolar cell under a constant deposition potential and using an ethanolic electrolyte solution containing stearic acid and montmorillonite. Stearic acid acts as an inexpensive and green coating while montmorillonite acts as a modifier to impart thermal stability. The gradient morphology of the nanoclusters was investigated by scanning electron microscopy,... 

    Modeling of retention behaviors of most frequent components of essential oils in polar and non-polar stationary phases

    , Article Journal of Separation Science ; Volume 34, Issue 13 , 2011 , Pages 1538-1546 ; 16159306 (ISSN) Jalali Heravi, M ; Ebrahimi Najafabadi, H ; Sharif University of Technology
    2011
    Abstract
    The gas chromatography retention indices of 100 different components of essential oils, on three columns with stationary phases of different polarities, were used to develop robust quantitative structure-retention relationship (QSRR) models. Two linear models with only one variable, i.e. solvation entropy, were developed, which explain 95 and 94% of variances of the test set for dimethyl silicone and dimethyl silicone with 5% phenyl group columns, respectively. These models are extremely simple and easy to interpret, but they show higher errors compared with more robust models such as partial least square (PLS) and ridge regressions. For the third column (polyethylene glycol (PEG)), 24... 

    The use of ladder particle swarm optimisation for quantitative structure-activity relationship analysis of human immunodeficiency virus-1 integrase inhibitors

    , Article Molecular Simulation ; Volume 37, Issue 15 , 2011 , Pages 1221-1233 ; 08927022 (ISSN) Jalali Heravi, M ; Ebrahimi-Najafabadi, H ; Sharif University of Technology
    2011
    Abstract
    This contribution focuses on the use of ladder particle swarm optimisation (LPSO) on modelling of oxadiazole- and triazolesubstituted naphthyridines as human immunodeficiency virus-1 integrase inhibitors. Artificial neural network (ANN) and Monte Carlo cross-validation techniques were combined with LPSO to develop a quantitative structure-activity relationship model. The techniques of LPSO, ANN and sample set partitioning based on joint x-y distances were applied as feature selection, mapping and model evaluation, respectively. The variables selected by LPSO were used as inputs of Bayesian regularisation ANN. The statistical parameters of correlation of deterministic, R2, and... 

    Fast Centralized Model Predictive Control of Signal Splitting in Large Scale Urban Road Networks

    , M.Sc. Thesis Sharif University of Technology Hosseini Najafabadi, Sajad (Author) ; Haeri, Mohammad (Supervisor)
    Abstract
    With the rapid increase in the number of vehicles and the limitations on the extension of transportation network infrastructure, the need for utilizing proper methods to reduce traffic congestion has become increasingly important. One way to reduce traffic congestion is to control the signal splitting of traffic lights. Model predictive control (MPC) has been utilized so far by using different models of traffic flow dynamics in this field. Due to the high computational effort of MPC at each step time, the real-time implementation for large-scale networks has become a big challenge. Store-And-forward (SAF) is one of the traffic flow models that, due to its simplicity, makes it possible to... 

    Mathematical performance modelling of adaptive wormhole routing in optoelectronic hypercubes

    , Article Journal of Parallel and Distributed Computing ; Volume 67, Issue 9 , Volume 67, Issue 9 , 2007 , Pages 967-980 ; 07437315 (ISSN) Hashemi Najafabadi, H ; Sarbazi Azad, H ; Sharif University of Technology
    2007
    Abstract
    In this paper, an analytical performance model for adaptive wormhole routing in the hypercube-based optical transpose interconnection system (OTIS-hypercube) is proposed and validated. Using this model, the performance merits of the OTIS-hypercube are discussed. We also compare the performance of the OTIS-hypercube with that of equivalent hypercube network under different implementation constraints. Compared to pure simulation results, the presented model can serve as a more appropriate and compact method to display the performance characteristics of OTIS-hypercube networks. © 2007 Elsevier Inc. All rights reserved  

    The Use of Non-platinum Electro-catalyst for Low Temperature Fuel Cells

    , M.Sc. Thesis Sharif University of Technology Hamzehie, Mohammad Ehsan (Author) ; Samiee, Leila (Supervisor) ; Seifkordi, Ali Akbar (Co-Advisor)
    Abstract
    In the recent decades, Polymer Electrolyte Membrane Fuel Cells (PEFC) have been known as an appropriate type of fuel cells, due to being electrochemical converter and clean energy generator with high power density and having low operation temperature and launch time. Palatine is one of the major materials that are used in electro-catalysts of fuel cell. Due to shortage of palatine resources and its high price, fuel cell production is not economical. To achieve economic conditions for production of fuel cell, two major methods are proposed:
    1) Reduction of the employed amount of palatine in electro-catalyst
    2) Full replacement of palatine with cheap materials
    In the current... 

    Copper(II) acetate

    , Article Synlett ; Volume 23, Issue 13 , 2012 , Pages 1995-1996 ; 09365214 (ISSN) Amini, M ; Sharif University of Technology
    2012
    Abstract
    (A) Chakraborty and co-workers have developed a green method for the bulk ring-opening polymerization of lactides in the presence of Cu(OAc)2 as a good catalyst to synthesize polymers with different end-terminal groups.3 These polymerizations are highly controlled leading to the formation of polymers with the expected number of average molecular weights and narrow molecular weight distribution. (B) Garden and co-workers have found that the oxidative addition of anilines with 1,4-naphthoquinone to give N-aryl-2-amino-1,4-naphthoquinones can be performed in the presence of catalytic amounts of copper(II) acetate.4 All the reactions are generally more efficient in that they are cleaner, higher... 

    Solving rank one revised linear systems by the scaled ABS method

    , Article ANZIAM Journal ; Volume 46, Issue 2 , 2004 , Pages 225-236 ; 14461811 (ISSN) Amini, K ; Sharif University of Technology
    2004
    Abstract
    In mathematical programming, an important tool is the use of active set strategies to update the current solution of a linear system after a rank one change in the constraint matrix. We show how to update the general solution of a linear system obtained by use of the scaled ABS method when the matrix coefficient is subjected to a rank one change. © Australian Mathematical Society 2004  

    Multiclass Visual Object Recognition Based On Cluttered Images

    , M.Sc. Thesis Sharif University of Technology Moghimi Najafabadi, Mohammad (Author) ; Kasaei, Shohreh (Supervisor)
    Abstract
    With the advancement of Machine Vision and Image Processing systems, the need for conceptual interpretation is raising. For this interpretation, one should detect objects available in the image and then tries to find the relations between the objects. For a good interpretation of the image, the machine vision system should learn patterns available in the nature. Object recognition systems are also used in other vision tasks and they can be used for content-based image retrieval, control and surveillance, or human action and gesture recognition for a better and easier human-computer interface. In an object recognition system, first some features should be extracted from the input image and... 

    Multisymplectic Geometry, Covariant Hamiltonian and Water Waves

    , M.Sc. Thesis Sharif University of Technology Nassaj Najafabadi, Akram (Author) ; Bahraini, Alireza (Supervisor)

    Blood Glucose Control in Human Body Using Model-Based Controllers

    , M.Sc. Thesis Sharif University of Technology Abedini Najafabadi, Hamed (Author) ; Shahrokhi, Mohammad (Supervisor)
    Abstract
    Continous blood glucose control has great importance for type 1 dyabetic patients. In this thesis, several types of controllers including: PI controller, model predictive controller base on state space model, linear model predictive controller base of linear input-output model and non-linear model predictive controller base of Hammerstein model have been used to regulate blood glucose of patients with type 1 diabetes. These models are identified using least squars method. Performance of these controllers is tested and the best one is introduced. For rejecting meal disturbances, a feedforward controller has been designed. Combination of feedback and feedforward controller would properly... 

    Estimation of biodiesel physical properties using local composition based models

    , Article Industrial and Engineering Chemistry Research ; Volume 51, Issue 41 , September , 2012 , Pages 13518-13526 ; 08885885 (ISSN) Abedini Najafabadi, H ; Pazuki, G ; Vossoughi, M ; Sharif University of Technology
    2012
    Abstract
    In this study, the local composition based models such as the Wilson, the nonrandom two-liquid (NRTL), and the Wilson-NRF have been applied in correlation and estimation of density, viscosity, and surface tension of biodiesels. The thermodynamic models have been used in correlating the thermophysical properties for 215 experimental data points. These models have the interaction energy between each pair that is considered as adjustable parameters. To decrease the number of these adjustable parameters, it is assumed that the biodiesels are composed of two hypothetical components. The average absolute deviation (AADs) of the correlated density of biodiesels for the Wilson, the NRTL, and the... 

    Performance analysis of contact baking of flat bread in an indirect-heating oven

    , Article Drying Technology ; Volume 30, Issue 9 , May , 2012 , Pages 1014-1023 ; 07373937 (ISSN) Karimi, G ; Feilizadeh, M ; Najafabadi, A. T ; Sharif University of Technology
    2012
    Abstract
    A significant portion of Iranian flat breads are produced in semi-industrial, indirect-heating ovens. Therefore, an efficient oven design and a proper selection of operating conditions are crucial to improve the product quality and reduce energy consumption. In the present study, a mathematical model is developed to simulate a semi-industrial, indirect-heating, continuous oven performance during contact baking of an Iranian flat bread, referred to as Taftoon. Individual modes of heat transfer are considered among various components of the baking system to estimate the system performance and the bread quality in terms of design and operating conditions. The predictions of this model are in...