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    Emotional learning based intelligent controller for MIMO peripheral milling process

    , Article Journal of Applied and Computational Mechanics ; Volume 6, Issue 3 , 2020 , Pages 480-492 Bahari Kordabad, A ; Boroushaki, M ; Sharif University of Technology
    Shahid Chamran University of Ahvaz  2020
    Abstract
    During the milling process, one of the most important factors in reducing tool life expectancy and quality of workpiece is the chattering phenomenon due to self-excitation. The milling process is considered as a MIMO strongly coupled nonlinear plant with time delay terms in cutting forces. We stabilize the plant using two independent Emotional Learning-based Intelligent Controller (ELIC) in parallel. Control inputs are considered as forces Ux and Uy in two directions x and y, which are applied by the piezoelectrics. The ELIC consists of three elements; Critic, TSK controller and the learning element. The results of the ELIC have been compared with a Sliding Mode Controller (SMC). The... 

    Cost-effective 3D H-filter fabricated by xurographic method

    , Article Microfluidics and Nanofluidics ; Volume 26, Issue 9 , 2022 ; 16134982 (ISSN) Bahari, A ; Mirzaei, A ; Taghipoor, M ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2022
    Abstract
    In this paper, the conventional 2D H-filter is modified to 3D multi-layer structures fabricated by low-cost xurography. The extraction efficiency was studied experimentally for different 3D structures and then compared with conventional 2D H-filter. Numerical simulations were performed to model the diffusion flow in the proposed H-filters, showing a good agreement with the experimental observations. Results show that 3D H-filters have higher extraction efficiency at the same Reynolds number. Moreover, these structures could benefit low-cost and commercial applications due to their higher efficiency at smaller sizes. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH... 

    Electrodeposition of long gold nanotubes in polycarbonate templates as highly sensitive 3D nanoelectrode ensembles

    , Article Electrochimica Acta ; Volume 75 , 2012 , Pages 157-163 ; 00134686 (ISSN) Bahari Mollamahalle, Y ; Ghorbani, M ; Dolati, A ; Sharif University of Technology
    Elsevier  2012
    Abstract
    Electrodeposition of long and well-defined gold nanotubes in polycarbonate (PC) templates is still a major concern due to pore blockage problems. In the present study, we introduce a novel method for electrodeposition of long gold nanotubes within the pores of PC templates for the first time. In order to deposit gold atoms onto the pore walls preferentially, pore walls were functionalized with a coupling agent. Short and thin Ni nanotubes were then electrodeposited at the bottom of the pores. Gold nanotubes were subsequently electrodeposited at constant potentials and low solution concentrations. The morphology of nanotubes was characterized by electron microscopy and their formation... 

    Application of 3D gold nanotube ensembles in electrochemical sensing of ultra-trace Hg (II) in drinkable water

    , Article Surfaces and Interfaces ; Volume 10 , 2018 , Pages 27-31 ; 24680230 (ISSN) Bahari Mollamahale, Y ; Ghorbani, M ; Dolati, A ; Ghalkhani, M ; Sharif University of Technology
    Elsevier B.V  2018
    Abstract
    As a novel and highly sensitive sensor, three-dimensional gold nanoelectrode ensembles (3D GNE) prepared by gold deposition inside the parallel pores of a porous template have been successfully applied in electrochemical determination experiments. In this study, we report on the fabrication of 3D gold nanotubes (GNT) and their application in determination of Hg (II) in water. The morphology and crystal structure of the 3D GNT were characterized by field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD), respectively. The sensitivity of the fabricated electrode towards Hg (II) was examined using anodic stripping voltammetry (ASV) as a powerful technique in... 

    Prediction of shape and internal structure of the proximal femur using a modified level set method for structural topology optimisation

    , Article Computer Methods in Biomechanics and Biomedical Engineering ; Volume 15, Issue 8 , 2012 , Pages 835-844 ; 10255842 (ISSN) Bahari, M. K ; Farahmand, F ; Rouhi, G ; Movahhedy, M. R ; Sharif University of Technology
    2012
    Abstract
    A computational framework was developed to simulate the bone remodelling process as a structural topology optimisation problem. The mathematical formulation of the Level Set technique was extended and then implemented into a coronal plane model of the proximal femur to simulate the remodelling of internal structure and external geometry of bone into the optimal state. Results indicated that the proposed approach could reasonably mimic the major geometrical and material features of the natural bone. Simulation of the internal bone remodelling on the typical gross shape of the proximal femur, resulted in a density distribution pattern with good consistency with that of the natural bone. When... 

    Synthesis and characterization of a new nanocomposite by filling of CNT with CoFe2O4 Magnetic nanoparticles and grafting to polymer

    , Article Nano ; Volume 4, Issue 6 , 2009 , Pages 371-376 ; 17932920 (ISSN) Sepahvand, R ; Adeli, M ; Actinchap, B ; Bahari, A ; Sharif University of Technology
    2009
    Abstract
    In this work, the synthesis and characterization of a new nanocomposite from carbon nanotubes-graft-polymer (CNTs-g-P) is reported. The products were obtained by the filling of multi-walled carbon nanotubes (MWCNTs) (inner diameter 2040 nm) with CoFe2O4 magnetic nanoparticles, been grafted with poly (caprolactone). The filling process was carried out by using acid treatment through wet chemistry. The structure and the properties of the new nanocomposite were studied with TEM, VSM, TGA, and spectroscopic techniques. © 2009 World Scientific Publishing Company  

    Smart water flooding performance in carbonate reservoirs: an experimental approach for tertiary oil recovery

    , Article Journal of Petroleum Exploration and Production Technology ; Volume 9, Issue 4 , 2019 , Pages 2643-2657 ; 21900558 (ISSN) Darvish Sarvestani, A ; Ayatollahi, S ; Bahari Moghaddam, M ; Sharif University of Technology
    Springer  2019
    Abstract
    Smart water flooding as a developing technique utilizes modified water chemistry in terms of salinity and composition to prepare the best-suited brine composition for a specific brine/oil/rock system to obtain higher oil recovery efficiency. Huge amount of unrecovered oil is expected to be remained in carbonate reservoirs; however, few research works on incremental oil recovery during smart water injection in carbonate cores at reservoir condition are reported. Several core flooding tests using one of the Iranian carbonate reservoir rock are conducted to check the effectiveness of smart water injection for more oil recovery efficiency. The results reaffirm the positive effect of sulfate ions... 

    Electrodeposition of well-defined gold nanowires with uniform ends for developing 3D nanoelectrode ensembles with enhanced sensitivity

    , Article Materials Chemistry and Physics ; Volume 213 , 2018 , Pages 67-75 ; 02540584 (ISSN) Bahari Mollamahale, Y ; Ghorbani, M ; Dolati, A ; Hosseini, D ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    Fabrication of well-defined gold nanowires (GNWs) is of significant importance in many fields such as sensing applications. In this study, the electrodeposition of well-defined GNWs inside polycarbonate (PC) template has been discussed in detail. GNWs were potentiostatically electrodeposited at different filling rates. The growth of GNWs at different stages of pore filling was monitored by electrochemical measurements and field-emission scanning electron microscopy (FE-SEM). It was confirmed that under growth rates between 2.5 and 4 nm/s, GNWs with smooth ends grew uniformly inside the template without any imperfections or corrugations. The length of GNWs was electrochemically controlled to... 

    A novel high gain extendable dc-dc bidirectional boost-buck converter

    , Article 11th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2020, 4 February 2020 through 6 February 2020 ; 2020 Hosseini, S. H ; Ghazi, R ; Farzamkia, S ; Bahari, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    Bidirectional DC/DC converters are so prevalent in several applications. Regarding some applications, increasing their voltage gain ratios (VTR) are quite important. So, this paper proposes a novel extendable bidirectional boost-buck converter. In this converter, any isolation and coupled inductors are not employed. Each stage is derived from fundamental bidirectional boost-buck converter with the same switching algorithms. By embedding n stages in topology, VTRs for step-up-step-down are multiplied $n$ times for step-down and step-up modes. Furthermore, a comprehensive comparison have provided in case of VTR and total voltage stress across active power switches. It can be seen that total... 

    Social Reality in John Searle: Do Institutional Facts have Physical Realization?

    , M.Sc. Thesis Sharif University of Technology Bahari, Amin (Author) ; Taqavi, Mostafa (Supervisor)
    Abstract
    In the extension of his former developments of the theories of philosophy of mind and language, John Searle (1932- ) proceeded into the realm of social reality by his The Construction of Social Reality and Making the Social World, written in 1995 and 2010 respectively. With his naturalistic background, he placed his new theory on top of his former theories of mind and language already naturalized and fully worked out. As we will see, social reality comes with our three marvelous capacities, not coming together, to the extent we know, in animals other than us: collective intentionality, assignment of function, and language; all of them already being treated by Searle, in a naturalized manner,... 

    Proposal of a fault-tolerance technique for 1-ph open circuit fault in resolvers

    , Article IEEE Sensors Journal ; Volume 21, Issue 14 , 2021 , Pages 15987-15992 ; 1530437X (ISSN) Bahari, M ; Tootoonchian, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    Due to their cost-effective manufacturing and robust structure, an electromagnetic sensor called resolver is being applied in a wide range of applications, especially in those which high reliability is particularly essential. Since resolvers are usually chosen as position detector units in harsh environments, their chronic exposure to high temperature and mechanical shocks is unpreventable and accordingly, performance failure as a result of output signal winding open circuit fault (OCF) is inevitable. In this paper, a new technique is proposed to keep the performance of the resolver within an acceptable range of position error while one of the output signals (SIN/COS) is inaccessible. To... 

    Performance analysis of an outer rotor variable reluctance resolver

    , Article IEEE Sensors Journal ; Volume 22, Issue 18 , 2022 , Pages 17761-17768 ; 1530437X (ISSN) Bahari, M ; Tootoonchian, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2022
    Abstract
    Variable reluctance resolver (VR-Resolver) is a robust electromagnetic sensor that provides position information for closed-loop control systems of permanent magnet synchronous motors (PMSMs). For specific motion control applications, an outer rotor structure is presented for the VR-Resolver in this article with a nonoverlapping tooth-coil windings configuration to simplify the manufacturing process. The study on the structure of the proposed position sensor is carried out, followed by the description of the working principle. The presented outer rotor VR-Resolver is simulated and its performance is investigated in detail with the aid of transient finite-element analysis (TFEA). Sensitivity... 

    Critical Realism and Futures Studies: the Influence of Roy Bhaskar on Sohail Inayatullah

    , M.Sc. Thesis Sharif University of Technology Bahari, Mojtaba (Author) ; Mousavi, Mirsaeid (Supervisor)
    Abstract
    Sohail Inayatullah is one of the most successful futurists of the last decade. His proposed method for futures studies, which is called Causal Layered Analysis (CLA), has attracted a lot of attention and has won futurists’ admiration. Although, Wendell Bell counts the study of epistemological foundations of futures studies as one of the major purposes in this field, unfortunately, no significant attempt has been made to clarify the epistemological foundation of CLA, up to this time. The primary purpose of this thesis is to relieve this weakness. Inayatullah calls his approach, in developing CLA, “critical”. On the other hand, Wendell Bell claims that Roy Bhaskar’s “critical realism” is an... 

    Design and Implementation of a Real-time Heuristic Algorithm for In-Motion Alignment of a Strapdown Inertial Navigation System

    , M.Sc. Thesis Sharif University of Technology Ashrafifar, Asghar (Author) ; Bahari, Hadi (Supervisor)
    Abstract
    In this work, the in-motion estimation of Euler angles of a strapdown inertial navigation system is studied using a speedometer, as an aided navigation sensor. First, the derivation of governing error equations has been done. Then, the most appropriate heuristic filters available in references have been chosen for this study. Among this filters, unscented particle filter, that has better performance and conditions for the real-time implementation, has been chosen. Then, an innovative solution for improving the performance of this filter is presented. The proposed filter uses particle swarm optimization to resample the particles. The proposed... 

    Longitudinal end effect in a variable area linear resolver and its compensating methods

    , Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 1316-1321 ; 9781538649169 (ISBN) Bahari, M ; Nasiri Gheidari, Z ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    Linear permanent magnet machines are increasingly used in industrial applications where they need position sensors to improve their performance. Variable Reluctance resolvers are one the best position sensors that can be used in unfriendly environment conditions, with high mechanical vibration, wide temperature variation and polluted environments. However, conventional VR resolvers suffer from complicated winding process, undesirable performance under eccentricities, and high position error in two-pole applications. So, in this paper a new linear resolver is proposed based on the sinusoidal variation of common area between the moving and the stationary parts. Then, the influence of... 

    Liposome Nanoparticles Synthesis in order to Study the Antibiotic Drug Delivery in Simulated Environment of Body

    , M.Sc. Thesis Sharif University of Technology Bahari, Mohsen (Author) ; Alemzadeh, Iran (Supervisor)
    Abstract
    In recent years, much attention has been paid to the preparation of nanoparticles as carriers for drug delivery. Nanoparticle carriers, by changing the pharmacokinetic properties of the drug, improve the function of the drug and reduce its side effects. In the manufacture of nanoparticles, various materials such as polymers, metal particles, lipids, etc. are used to transfer the drugs, which can produce a different shape and size of the particles depending on their production method. The purpose of this project is the synthesis of liposomal nanoparticles (as nano-carriers) to load an antibiotic (Eucalyptus oil) and study the release of the encapsulated drug in the simulated environment of... 

    The comparative analysis of AC- ux and DC- ux resolvers

    , Article Scientia Iranica ; Volume 29, Issue 4 , 2022 , Pages 2007-2013 ; 10263098 (ISSN) Bahari, M ; Nasiri Gheidari, Z ; Sharif University of Technology
    Sharif University of Technology  2022
    Abstract
    Resolver, as an electromagnetic sensor, is widely used in many industrial applications. It can detect the position of the rotary part of the electric machines precisely. In commercial resolvers, excitation winding is connected to the High-Frequency (HF) AC source. The amplitude-modulated voltages induced in signal windings need to be demodulated in order to calculate the envelope of the output signals and detect the position accordingly. On the other hand, in PM-resolver, signal windings are replaced by Hall-effect sensors to measure the DC magnetic ux, which is produced by permanent magnets. In this study, the performance of both AC and DC ux resolvers is investigated under di erent... 

    RKPM with Etxtended Augmented Corrected Collocation Method for Treatment of Lamellar Inhomogeneitie

    , M.Sc. Thesis Sharif University of Technology Bahari, Behnaz (Author) ; Mohammadi Shoja, Hossein (Supervisor)
    Abstract
    An accurate numerical methodology for capturing the field quantities a center lamellar inhomogeneity within the interface of two different phases of a bimaterial rectangular plate subjected to non-uniform tensile stress, in the context of reproducing kernel particle method (RKPM), is of particular interest. For this purpose the innovative numerical technique, so-called extended augmented corrected collocation method is introduced; this technique is an extension of the augmented corrected collocation method used for imposing continuity condition of the displacement at the interface. The robustness of this methodology is shown by solving problems of material discontinuities, namely plates... 

    A Thesis Submitted in Partial Fulfillment of the Requirement for the Degree of Master of Science in Digital Systems

    , M.Sc. Thesis Sharif University of Technology Bahari, Mohammad Hossein (Author) ; Shabany, Mahdi (Supervisor)
    Abstract
    Massive-MIMO and C-RAN are the two technologies which will be among most important parts of fifth generation (5G) stsrems. They will find widespread uses in future years. However, data transfer rate between these two technologies is a challenging problem. Also channel estimation is crucial in massive-MIMO systems. In this research, the problem of estimating the channel and the problems with the data transfer rate between these two technologies are investigated. We propose using 1-bit quantizers to solve the rate problem and also an algorithm with perfect performance in aspect of error rate is proposed. The mentioned algorithm is implemented on GPUs, which are available at C-RANs and resulted... 

    Control of Bifurcation and Chatter Suppression in Peripheral Milling Process

    , M.Sc. Thesis Sharif University of Technology Bahari Kordabad, Arash (Author) ; Moradi, Hamed (Supervisor)
    Abstract
    Self-excitation vibration or chatter in the milling process is one of the most critical factors in reducing the tool life and surface smoothness. With the change of tool speed or depth of cut, bifurcation phenomena occur at some points (bifurcation points) such that the system behaviour becomes unstable and the chatter is observed. In this study, using nonlinear modelling for cutting forces, two main methods for active control of this process are proposed. The first is an intelligent control based on emotional learning, which is a model-free strategy. In this method, the critic generates a signal (stress signal) using error and its derivative. The purpose of this controller is to reduce the...