Search for: jokar--s
0.128 seconds

    Dynamic based cost functions for TF/TA flights

    , Article 2005 IEEE Aerospace Conference, Big Sky, MT, 5 March 2005 through 12 March 2005 ; Volume 2005 , 2005 ; 1095323X (ISSN); 0780388704 (ISBN); 9780780388703 (ISBN) Malaek, S. M ; Kosari, A. R ; Jokar, S ; Sharif University of Technology
    A new methodology has been proposed which offers a systematic approach to use the so called "performance index" or cost function as the basic tool to incorporate the dynamics of the aircraft in the process of trajectory planning. Moreover, by using non-dimensional parameters a better understanding of the dynamic terms are provided. © 2005 IEEE  

    Developing a model for a two-echelon two-item inventory system with lost sale and demand substitution

    , Article 2006 IEEE International Conference on Management of Innovation and Technology, ICMIT 2006, Singapore, 21 June 2006 through 23 June 2006 ; Volume 2 , 2006 , Pages 926-930 ; 1424401488 (ISBN); 9781424401482 (ISBN) Akbari Jokar, M. R ; Zangeneh, S ; Sharif University of Technology
    Almost all multi-echelon inventory models assume that demands which are not satisfied immediately can be backordered. In some situations, this assumption may not be realistic. For example, we can model stockouts as lost sales when the retailers are in a competitive market and customers can easily turn to another retailer for purchasing goods. So, in this study, assuming lost sales at the retailers, we consider a one-warehouse, several retailers, two-item inventory system where the items can be interchangeably used. Using the well-known METRIC-approximation as a framework, we present a heuristic for finding cost effective base-stock policies. In a numerical study with simulation, we find that... 

    Functionalized mesoporous silica-coated magnetic graphene oxide by polyglycerol-g-polycaprolactone with pH-responsive behavior: designed for targeted and controlled doxorubicin delivery

    , Article Journal of Industrial and Engineering Chemistry ; 2015 ; ISSN: 1226086X Pourjavadi, A ; Tehrani, Z. M ; Jokar, S ; Sharif University of Technology
    In the present work a novel multifunctional drug nanocarrier was prepared. Polyglycerol-. g-polycaprolactone was grafted on Mesoporous silica-coated magnetic graphene oxide. Doxorubicin, as anticancer drug, was loaded on this carrier. The in vitro drug release showed the controlled pH responsive behavior. At the endosomal pH (pH 5.5) the amount of drug release enhanced. This nanocarrier would have potential application in the tumor therapy owing to its biodegradability, controlled release and pH responsive behavior  

    Electrochemical functionalization of graphene nanosheets with catechol derivatives as an effective method for preparation of highly performance supercapacitors

    , Article Electrochimica Acta ; Vol. 147, issue , 2014 , pp. 136-142 ; ISSN: 00134686 Jokar, E ; Shahrokhian, S ; Zad, A. I ; Sharif University of Technology
    Performance enhancement of supercapacitors has been recently discussed. In this paper a novel and facile procedure for functionalization of graphene with some electroactive molecules is presented. The graphene has been functionalized by catechol-based molecules, which are electroactive molecules with electrochemically reversible properties. The functionalized graphene exhibits very effective pseudocapacitor behaviorfor charge storage. For the first time, with the aim of an electrosynthesis procedure, catechol is covalently attached on graphene sheets. This attachment has been investigated by electrochemical, X-ray photoelectron spectroscopy and attenuated total reflectance methods. Catechol... 

    Synthesis and characterization of NiCo2O4 nanorods for preparation of supercapacitor electrodes

    , Article Journal of Solid State Electrochemistry ; Vol. 19, Issue. 1 , 2014 , pp. 269-274 ; ISSN: 1432-8488 Jokar, E ; Zad, A. I ; Shahrokhian, S ; Sharif University of Technology
    Here, a solvothermal method for synthesis of porous Ni–Co binary oxide (NiCo2O4) nanorods followed by thermal decomposition is described. The prepared nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer Emmett Teller (BET) methods. These porous NiCo2O4 nanostructures were promising candidates in the development of high capacity supercapacitors and having excellent cycling performance due to high specific surface area. In addition, the influence of annealing rate on the structure and electrochemical behavior of the synthesized nanorods was investigated. The results showed that the annealing rate had a direct effect on the crystalline... 

    Constructing a block layout by face area

    , Article International Journal of Advanced Manufacturing Technology ; Volume 54, Issue 5-8 , 2011 , Pages 801-809 ; 02683768 (ISSN) Jokar, M. R. A ; Sangchooli, A. S ; Sharif University of Technology
    Solving the facility layout problems by graph theory consists of two stages. In the first stage, a planar graph that specifies desired adjacencies is obtained and in the second stage, a block layout is achieved from the planar graph. In this paper, we introduce face area as a new concept for constructing a block layout. Based on this idea, we present a new algorithm for constructing block layout from a maximal planar graph (MPG). This MPG must be generated from deltahedron heuristic. Constructed block layout by this algorithm satisfies all of adjacency and area requirements  

    Chitosan based supramolecular polypseudorotaxane as a pH-responsive polymer and their hybridization with mesoporous silica-coated magnetic graphene oxide for triggered anticancer drug delivery

    , Article Polymer (United Kingdom) ; Volume 76 , October , 2015 , Pages 52-61 ; 00323861 (ISSN) Pourjavadi, A ; Mazaheri Tehrani, Z ; Jokar, S ; Sharif University of Technology
    Elsevier Ltd  2015
    Chitosan based polyseudorotaxane was designed as a pH-responsive supramolecular polymeric shell around the mesoporous silica-coated magnetic graphene oxide (Fe3O4@GO@mSiO2). It was used for doxorubicin delivery at cancerous tissue in a controlled manner. The core-shell nanocarrier was formed due to electrostatic interaction between chitosan and carboxylated surface of Fe3O4@GO@mSiO2. The maximum release occurred at pH 5.5 (pH of endosomes) because the shell collapsed at this pH. The drug nanocarrier has potential application in tumor therapy due to good pH-sensitive behavior, improved solubility and high colloidal stability in... 

    In-situ electro-polymerization of graphene nanoribbon/polyaniline composite film: Application to sensitive electrochemical detection of dobutamine

    , Article Sensors and Actuators, B: Chemical ; Vol. 196 , June , 2014 , pp. 582-588 ; ISSN: 09254005 Asadian, E ; Shahrokhian, S ; Zad, A. I ; Jokar, E ; Sharif University of Technology
    The present paper demonstrates the capability of narrow graphene nanoribbons (GNRs) in constructing new sensing platforms. Graphene nanoribbons have been synthesized via a simple solvothermal route through unzipping of carbon nanotubes, which was confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy analysis. These narrow carbon sheets were used to form a composite film by in-situ electro-polymerization with aniline. The produced graphene nanoribbon/polyaniline (GNR/PANI) composite film showed impressive performance in electrochemical determination of dobutamine (DBT). Under optimal conditions, in comparison to... 

    A survey on multi-floor facility layout problems

    , Article Computers and Industrial Engineering ; Volume 107 , 2017 , Pages 158-170 ; 03608352 (ISSN) Ahmadi, A ; Pishvaee, M. S ; Akbari Jokar, M. R ; Sharif University of Technology
    Facility layout problem is a well-known optimization problem which generally deals with the arrangement of the facilities required in an organization. This problem has received much attention during the past decades. However, the researchers have mainly focused on the case where a single floor is available. While, in the competitive world, it is clear that using multi-floor structure layouts are much more efficient and in some cases necessary due to the nature of the functions and activities performed in the firms. Hence, this issue has recently attracted much attention and is becoming increasingly popular. Nevertheless, the lack of a review study on this subject for directing the new... 

    A fast kinematic-based control method for lower-limb power augmentation exoskeleton

    , Article 2014 2nd RSI/ISM International Conference on Robotics and Mechatronics, ICRoM 2014 ; 2014 , pp. 678-683 ; ISBN: 9781479967438 Taherifar, A ; Vossoughi, G. R ; Ghafari, A. S ; Jokar, M ; Sharif University of Technology
    Exoskeletons are robotic devices which are used in power augmentation and rehabilitation robotics. The exoskeleton control system is one of the most challenging issues in humanrobot interaction systems. Although the rehabilitation robotic control methods are well studied, little research has been conducted on power augmenting control methods. This paper presents a novel idea in control system of exoskeletons for load carrying and power augmentation. Here, the desired linear velocity of the exoskeleton in interaction points are taken to be proportional to interaction force at the corresponding location. The introduced control method is merely based on kinematic model and thus easy to... 

    Characterization of three-dimensional reduced graphene oxide/copper oxide heterostructures for hydrogen sulfide gas sensing application

    , Article Journal of Alloys and Compounds ; Volume 740 , 2018 , Pages 1024-1031 ; 09258388 (ISSN) Mirmotallebi, M ; Iraji zad, A ; Hosseini, Z. S ; Jokar, E ; Sharif University of Technology
    Elsevier Ltd  2018
    Three-dimensional reduced graphene oxide (3D-rGO) structures decorated with CuO particles (GCu) are synthesized through a simple and scalable method for detection of hydrogen sulfide (H2S) gas. For characterization and investigation of porous structure various techniques were employed. Decorated 3D structures demonstrated higher sensitivity and selectivity in comparison to pure structure. Optimized structure for sensing was obtained through introducing different amounts of CuO. The GCu heterostructures containing 35 μmol of CuO powder demonstrated reproducible response of about 30% to the concentration of 10 ppm at room temperature, while complete recovery was obtained through heating to 150... 

    Hardware-algorithm co-design of a compressed fuzzy active learning method

    , Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 67, Issue 12 , July , 2020 , Pages 4932-4945 Jokar, E ; Klidbary, S. H ; Abolfathi, H ; Shouraki, S. B ; Zand, R ; Ahmadi, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Active learning method (ALM) is a powerful fuzzy-based soft computing methodology suitable for various applications such as function modeling, control systems, clustering and classification. Despite considerable advantages, the main computational engine of ALM, ink drop spread (IDS), is memory-intensive, which imposes significant area overheads in the hardware realization of the ALM for real-time applications. In this paper, we propose a compressed model for ALM which greatly alleviates the storage limitations. The proposed approach employs a distinct inference algorithm, enabling a significant reduction in memory utilization from O(N2) to O(2N) for a multi-input single-output (MISO) system.... 

    An efficient two-step approach for improvement of graphene aerogel characteristics in preparation of supercapacitor electrodes

    , Article Journal of Energy Storage ; Volume 17 , 2018 , Pages 465-473 ; 2352152X (ISSN) Jokar, E ; Shahrokhian, S ; zad, A. I ; Asadian, E ; Hosseini, H ; Sharif University of Technology
    Elsevier Ltd  2018
    We fabricated a high rate capability supercapacitor based on fluorine-doped graphene-carbon nanotubes aerogel network (G-CNT-F). Based on the electrochemical impedance spectroscopy data, the fluorination decreases the charge transfer resistance of graphene sheets, while CNTs act as spacer in the 3D structure. Therefore, both treatments improved the electrochemical properties of the resulted aerogel. Based on the Fourier transform infrared spectroscopy and XPS results, these excellent performances are attributed to semi-ionic bonds between fluorine and carbon. The specific capacitance of the graphene aerogel showed 78% decrease, when discharge current increases from 2 to 40 mA, while the... 

    Applying ultrasonic fields to separate water contained in medium-gravity crude oil emulsions and determining crude oil adhesion coefficients

    , Article Ultrasonics Sonochemistry ; Volume 70 , 2021 ; 13504177 (ISSN) Sadatshojaie, A ; Wood, D. A ; Jokar, S. M ; Rahimpour, M. R ; Sharif University of Technology
    Elsevier B.V  2021
    Separating produced water is a key part of production processing for most crude oils. It is required for quality reasons, and to avoid unnecessary transportation costs and prevent pipework corrosion rates caused by soluble salts present in the water. A complicating factor is that water is often present in crude oil in the form of emulsions. Experiments were performed to evaluate the performance of ultrasonic fields in demulsifying crude oil emulsions using novel pipe-form equipment. A horn-type piezoelectric ultrasonic transducer with a frequency of 20 kHz and power ranging from 80 W to 1000 W was used for experimental purposes. The influences of the intensity of ultrasonic fields,... 

    Corrigendum to “Applying ultrasonic fields to separate water contained in medium-gravity emulsions and determining adhesion coefficients” [Ultrasonics Sonochemistry 70 (2021) 105303] (Ultrasonics Sonochemistry (2021) 70, (S1350417720307112), (10.1016/j.ultsonch.2020.105303))

    , Article Ultrasonics Sonochemistry ; Volume 72 , 2021 ; 13504177 (ISSN) Sadatshojaie, A ; Wood, D. A ; Jokar, S. M ; Rahimpour, M. R ; Sharif University of Technology
    Elsevier B.V  2021
    In the original publication, The title of the paper is incorrect. Title should be state “Applying ultrasonic fields to separate water contained in medium-gravity emulsions and determining adhesion coefficients”. The authors would like to apologise for any inconvenience caused. © 2020 Elsevier B.V  

    Electromechanical resonator based on electrostatically actuated graphene-doped PVP nanofibers

    , Article Nanotechnology ; Volume 24, Issue 13 , 2013 ; 09574484 (ISSN) Fardindoost, S ; Mohammadi, S ; Zad, A. I ; Sarvari, R ; Shariat Panahi, S. P ; Jokar, E ; Sharif University of Technology
    In this paper we present experimental results describing electrical readout of the mechanical vibratory response of graphene-doped fibers by employing electrical actuation. For a fiber resonator with an approximate radius of 850 nm and length of 100 m, we observed a resonance frequency around 580 kHz with a quality factor (Q) of about 2511 in air at ambient conditions. Through the use of finite element simulations, we show that the reported frequency of resonance is relevant. We also show that the resonance frequency of the fiber resonators decreases as the bias potential is increased due to the electrostatic spring-softening effect  

    Electrochemical Determination of Piroxicam at thin Carbon
    Nanoparticle Composite And Investigation of the Electrochemical Behavior and Synthesis of Catechols in the Presence of Mercapto Methyl Tetrazol as a Nucleophile

    , M.Sc. Thesis Sharif University of Technology Jokar, Effat (Author) ; Shahrokhian, Saeed (Supervisor)
    The electrochemical oxidation behavior of the anti-inflammatory drug piroxicam was investigated. A carbon nanoparticle (CNP)-chitosan (CS) film-coated graphite electrode (PGE) was fabricated and the electrochemical behaviors of piroxicam on its surface was investigated by the means of cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). In comparison to the bare PGE, at the surface of the CNP-CS film modified electrode, the oxidation peak current of piroxicam increased significantly and the peak potential shifted negatively. Consequently, a simple and sensitive electroanalytical method was developed for the determination of piroxicam. The... 

    A Survey on Passing Sight Distance on Two-lane highways According to Road Conditions and Drivers' Behavior in Iran

    , M.Sc. Thesis Sharif University of Technology Jokar, Hadi (Author) ; Vaziri, Manouchehr (Supervisor)
    The main factor ensuring safety of passing maneuvers on two lane highways is known as Passing Sight Distance (PSD). The criteria presented in Iran's code and AASHTO Green book are provided by the results of researches conducted between years 1938 & 1941 in the United States. This research intends to find out whether some changes should be applied to the PSD criteria according to current vehicles' performance and driving behavior in Iran. For this purpose, about 8 hours of video films has been recorded from 3 different sites chosen from two-lane highways in Iran, resulted in 326 passing records. In the case of passing of two passenger cars The models provided by analyzing the videos show that... 

    Investigation on Hydrodynamic Locomotion of Sea Turtle

    , M.Sc. Thesis Sharif University of Technology Jokar, Mohammad (Author) ; Abbaspour, Madjid (Supervisor)
    Nowadays, underwater vehicles designed by getting inspiration from aquatic animals’ motions have considerable merits; therefore, the issue of designing and building such vehicles has great significance. One of the aquatic animals, which can be a source of inspiration for designing vehicles with optimized propulsion and maneuver ability, is turtle. In order to design a robot under the inspiration of turtle locomotion, at first, it requires analyzing its locomotion carefully. In this project, it has been tried to do so. Having examined the motions of turtles and other aquatic animals thoroughly, the basics of their motions are achieved. Next, the locomotion of both sea and pond turtle are... 

    Digital multiplierless realization of a calcium-based plasticity model

    , Article IEEE Transactions on Circuits and Systems II: Express Briefs ; Volume 64, Issue 7 , 2017 , Pages 832-836 ; 15497747 (ISSN) Jokar, E ; Soleimani, H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2017
    Calcium is a highly widespread and versatile intracellular ion that can control a wide range of temporal dynamics in the brain such as synaptic plasticity. This brief presents a novel and efficient digital circuit for implementing a calcium-based plasticity model aimed at reproducing relevant biological dynamics. Accordingly, we investigate the feasibility of the proposed model in a minimal neural network stressing on the effect of calcium oscillations on synaptic plasticity with various neuronal stimulation protocols. MATLAB simulations and physical implementations on field-programmable gate array confirm that the proposed model, with considerably low hardware overhead, can fairly mimic the...