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hosseini-tehrani--yas
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An efficient solution to measure inductance on-the-fly
, Article Measurement: Journal of the International Measurement Confederation ; Volume 223 , 2023 ; 02632241 (ISSN) ; Atarodi, M ; Sharif University of Technology
Elsevier B.V
2023
Abstract
Magnetic components such as inductors have supreme importance in switch-mode power supplies (SMPS). The design of the SMPS circuit is typically based on the information obtained from simulations and available datasheets. However, the behavior of the implemented circuit can deviate from expectation due to its time-varying characteristics, operation point, and various environmental factors. Therefore, advanced methods are required to measure the behavior of inductors in-circuit. To address this challenge, an in-circuit measurement solution based on the energy transfer characteristic of the inductance is presented. It is a cost-effective and easy-to-implement solution that can be integrated...
Dendritic magnetite decorated by pH-responsive PEGylated starch: A smart multifunctional nanocarrier for the triggered release of anti-cancer drugs
, Article RSC Advances ; Volume 5, Issue 60 , Jun , 2015 , Pages 48586-48595 ; 20462069 (ISSN) ; Mazaheri Tehrani, Z ; Hosseini, S. H ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
In the present study, we designed a pH-responsive drug nanocarrier based on polyamidoamine-modified Fe3 O4 nanoparticles coated by PEGylated starch-co-poly(acrylic acid). This carrier was used for the controlled release of doxorubicin as an anticancer drug model. The purpose of using the polyethylene glycol moiety is to generate a biostable nanocarrier in blood stream as it has been reported widely in the pharmaceutical literature. The use of a poly(acrylic acid) segment also provided pH-sensitivity to the polymer. Besides, the magnetic nanoparticles facilitate the cancer cell targeting with an external magnetic field located near the tumor site. This carrier was...
A Novel Energy Efficient Method for LoRa Network with Practical Implementation
, Ph.D. Dissertation Sharif University of Technology ; Atarodi, Mojtaba (Supervisor) ; Amini, Arash (Co-Supervisor)
Abstract
The Internet of things (IoT) is an emerging technology, encompassing wide aspects of applications. It provides intelligent connections between objects, devices, and living creatures. The IoT devices are mostly powered by limited energy sources like batteries. Therefore, optimizing their power consumption is necessary. First, this idea will be examined from different perspectives and then its applications and challenges in various fields and areas will be presented. The IoT applications require low-cost, low-energy, reliable, robust, secure, and scalable networks. The Low-power Wide-Area Network (LPWAN) is considered as one of the most potential solutions for IoT in the near future due to its...
Three-dimensional free vibration analysis of functionally graded piezoelectric annular plates on elastic foundations
, Article Meccanica ; Volume 47, Issue 6 , December , 2012 , Pages 1401-1423 ; 00256455 (ISSN) ; Jodaei, A ; Irandoust, S ; Aghdam, M. N ; Sharif University of Technology
Springer
2012
Abstract
Three-dimensional free vibration analysis of functionally graded piezoelectric (FGPM) annular plates resting on Pasternak foundations with different boundary conditions is presented. The material properties are assumed to have an exponent-law variation along the thickness. A semi-Analytical approach which makes use of state-space method in thickness direction and one-dimensional differential quadrature method in radial direction is utilized to obtain the influences of the Winkler and shearing layer elastic coefficients of the foundations on the non-dimensional natural frequencies of functionally graded piezoelectric annular plates. The analytical solution in the thickness direction can be...
Structural health monitoring of nonlinear structures using real-time hysteresis loop analysis
, M.Sc. Thesis Sharif University of Technology ; Rahimzadeh Rofooei, Fayaz (Supervisor) ; Mahdavi, Hossein (Co-Supervisor)
Abstract
Under conventional seismic design strategies, civil engineering structures are designed to undergo inelastic deformation to dissipate earthquake energy, leading to residual displacements and nonlinear deformations in the structure. As a result, there is an essential need for structural health monitoring methods to detect and process these nonlinear behaviors. In this dissertation, a model-free Hysteresis Loop Analysis (HLA) method is developed to identify damage and monitor the structure's performance online, under the earthquake excitations in both severe linear and nonlinear scenarios. The structural models used to validate this method includes three types of one-story, five-story, and...
Catalytic activity of the spinel ferrite nanocrystals on the growth of carbon nanotubes
, Article Journal of Superconductivity and Novel Magnetism ; Volume 26, Issue 2 , 2013 , Pages 429-435 ; 15571939 (ISSN) ; Daadmehr, V ; Rezakhani, A. T ; Shahbaz Tehrani, F ; Aghakhani, F ; Gholipour, S ; Sharif University of Technology
2013
Abstract
We prepared three ferrite nanocatalysts: (i) copper ferrite (CuFe 2O4) (ii) ferrite where cobalt was substituted by nickel (Nix Co1-x Fe2O4, with x=0, 0.2, 0.4, 0.6), and (iii) ferrite where nickel was substituted by zinc (Zn y Ni1-y Fe2O4 with y=1, 0.7, 0.5, 0.3), by the sol-gel method. The X-ray diffraction patterns show that the ferrite samples have been crystallized in the cubic spinel structural phase. We obtained the size of grains by field emission scanning electron microscopy images and their magnetic properties by vibrating sample magnetometer. Next, carbon nanotubes were grown on these nanocatalysts by the catalytic chemical vapor deposition method. We show that the catalytic...
Mesoporous silica nanoparticles (MCM-41) coated PEGylated chitosan as a pH-Responsive nanocarrier for triggered release of erythromycin [electronic resource]
, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; 2014, Volume 63, Issue 13, Pages 692-697 ; Mazaheri Tehrani, Zahra ; Sharif University of Technology
Abstract
A pH-responsive drug delivery system based on core shell structure of mesoporous silica nanoparticle (MSN) and chitosan-PEG copolymer was prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and high-resolution transmission microscope (HR-TEM) techniques. In order to improve compatibility MSN and drug, mesoporous nanosilica was modified by 3-aminopropyl triethoxysilane. The release of erythromycin (a macrolide antibiotic) as a model drug was investigated in two pHs, 7.4 and 5.5
Investigation of particle dispersion and deposition in a channel with elliptic obstructions using lattice Boltzmann method
, Article 2012 7th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, NEMS 2012, 5 March 2012 through 8 March 2012 ; March , 2012 , Pages 523-528 ; 9781467311243 (ISBN) ; Moosavi, A ; Sharif University of Technology
2012
Abstract
Particle transport and deposition in a channel flow with elliptic obstruction is studied. Numerical simulation of fluid flow is performed using two-dimensional lattice Boltzmann method, while one-way coupling Lagrangian method for particle tracking is used. Standard particles are injected in the inlet of the channel. Gravity, Drag force, Brownian forces, and the Saffman lift are considered in equation of particle motion. The influence of geometrical parameter, ellipse aspect ratio, is studied on dispersion and deposition of particles as well as the flow parameters, such as Reynolds number. In addition, the effect of particles size -particles of 0.01-10μm in diameter- on dispersion and...
A fem study of the overlapping ratio effect on superplastic formation of metal matrix composites
, Article 27th Congress of the International Council of the Aeronautical Sciences 2010, ICAS 2010, 19 September 2010 through 24 September 2010, Nice ; Volume 3 , 2010 , Pages 1836-1843 ; 9781617820496 (ISBN) ; Abedian, A ; Sharif University of Technology
2010
Abstract
In aerospace applications structures weight is considered as a major performance parameter. One of the most effective manufacturing methods for weight reduction is superplastic forming. By this technique, not only the weight, but also the stress concentration, the cost, and the manufacturing time are noticeably reduced. Additionally, the components with complicated shapes could be formed in a single manufacturing step. Due to the wide demand for whiskers reinforced metal matrix composites (MMCs) in aerospace industries, many research works have been designed to extend the borders of superplastic forming to MMCs materials. In the present study, a 3-D symmetric micromechanical finite element...
FEM Analysis of the Effects of Geometric Parameters on the Superplastic Forming of Metal Matrix Composit
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
In aerospace applications, the weight of structures is considered as a major performance parameter. One of the most effective ways for weight reduction is then attributed to the structurally continuous manufacturing of mechanical components. In this way, not only the weight, but also the stress concentration, the cost, joints and fasteners applications, and the time of manufacturing are noticeably reduced. With this method, components with complicated shapes could be formed in a single manufacturing step. Special specification of whisker reinforced Metal Matrix Composites (MMC’s) has made these materials very attractive for the aerospace applications.That is why the superplastic forming of...
Comparison of gas phase intrinsic properties of cytosine and thymine nucleobases with their O-alkyl adducts: Different hydrogen bonding preferences for thymine versus O-alkyl thymine
, Article Journal of Molecular Modeling ; Volume 19, Issue 8 , 2013 , Pages 2993-3005 ; 16102940 (ISSN) ; Fattahi, A ; Sharif University of Technology
2013
Abstract
In recent years, there has been increasing interest in damaged DNA and RNA nucleobases. These damaged nucleobases can cause DNA mutation, resulting in various diseases such as cancer. Alkylating agents are mutagenic and carcinogenic in a variety of prokaryotic and eukaryotic organisms. The present study employs density functional theory (DFT/B3LYP) with the 6-311++G(d,p) basis set to investigate the effect of chemical damage in O-alkyl pyrimidines such as O4-methylthymine, O2-methylcytosine and O 2-methylthymine. We compared the intrinsic properties, such as proton affinities, gas phase acidities, equilibrium tautomerization and nucleobase pair's hydrogen bonding properties, of these...
Conformational aspects of glutathione tripeptide: Electron density topological & natural bond orbital analyses
, Article Structural Chemistry ; Volume 24, Issue 1 , 2013 , Pages 147-158 ; 10400400 (ISSN) ; Fattahi, A ; Sharif University of Technology
2013
Abstract
Glutathione tripeptide (γ-glutamyl-cysteinyl-glycine) is a flexible molecule and its conformational energy landscape is strongly influenced by forming intramolecular hydrogen bond, its charge and the environment. This study employs DFT-B3LYP method with the 6-31+G (d,p) basis set to carry out conformational analysis of neutral, zwitterionic, cationic, and anionic forms of glutathione. In analyzing the structural characteristics of these structures, intramolecular hydrogen bonds were identified and characterized in details by topological parameters such as electron density ρ(r) and Laplacian of electron density Δ2 ρ(r) from Bader's atom in molecules theory. Charge transfer energies based on...
Bifurcation structure of two coupled FHN neurons with delay
, Article Mathematical Biosciences ; Volume 270 , 2015 , Pages 41-56 ; 00255564 (ISSN) ; Razvan, M ; Sharif University of Technology
Elsevier Inc
2015
Abstract
This paper presents an investigation of the dynamics of two coupled non-identical FitzHugh-Nagumo neurons with delayed synaptic connection. We consider coupling strength and time delay as bifurcation parameters, and try to classify all possible dynamics which is fairly rich. The neural system exhibits a unique rest point or three ones for the different values of coupling strength by employing the pitchfork bifurcation of non-trivial rest point. The asymptotic stability and possible Hopf bifurcations of the trivial rest point are studied by analyzing the corresponding characteristic equation. Homoclinic, fold, and pitchfork bifurcations of limit cycles are found. The delay-dependent stability...
Mesoporous silica nanoparticles with bilayer coating of poly(acrylic acid-co-itaconic acid) and human serum albumin (HSA): A pH-sensitive carrier for gemcitabine delivery
, Article Materials Science and Engineering C ; Volume 61 , 2016 , Pages 782-790 ; 09284931 (ISSN) ; Mazaheri Tehrani, Z ; Sharif University of Technology
2016
Abstract
Novel bilayer coated mesoporous silica nanoparticle (MCM-41) based on pH sensitive poly(acrylic acid-co-itaconic acid) and human serum albumin (HSA) was designed for controlled delivery of gemcitabine (anticancer drug) to cancer cells. The shell around the mesoporous silica has bilayer structure. Poly(acrylic acid-co-itaconic acid) was used as pH-sensitive inner shell and human serum albumin, HSA, was used as outer shell. The core-shell structure was formed due to electrostatic interaction between ammonium groups of modified MCM-41 and carboxylate groups of copolymer. Also, the albumin layer was wrapped around the copolymer coated nanoparticle by electrostatic interaction between ammonium...
Poly(N-isopropylacrylamide)-coated β-cyclodextrin–capped magnetic mesoporous silica nanoparticles exhibiting thermal and pH dual response for triggered anticancer drug delivery
, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 66, Issue 7 , 2017 , Pages 336-348 ; 00914037 (ISSN) ; Mazaheri Tehrani, Z ; Sharif University of Technology
Taylor and Francis Inc
2017
Abstract
In this research a novel controlled anticancer drug delivery system with dual pH and thermal responses was designed based on magnetic mesoporous silica nanoparticles that were anchored by β-cyclodextrin and coated by poly(N-isopropylacrylamide) (PNIPAM). Results demonstrated that the behavior of doxorubicin (anticancer drug) release depended on pH and temperature conditions. At endosomal pH (pH 5.5) the amount of drug release enhanced because the cap was removed from the pores. Furthermore, PNIPAM shell collapsed above the lower critical solution temperature and the releasing of drug increased. Thus, this nanocarrier would have the potential to be applied in the tumor therapy. © 2017 Taylor...
Design & Implementation of high dynamic range current measurement system for Iot applications
, Article IEEE Transactions on Instrumentation and Measurement ; Volume 71 , 2022 ; 00189456 (ISSN) ; Atarodi, S. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Internet-of-Things (IoT) devices have a strict necessity for power consumption to achieve the expected battery life. Therefore, measuring and optimizing the energy consumption of IoT nodes are essential. IoT nodes feature extreme current consumption range over 100 dB between their operating modes. The main focus of this article is to design and implement a low-power and low-cost current measurement circuit, which can be integrated into IoT nodes. A new pass element is introduced for measuring the current consumption. This element is placed in the current path to measure current over a high dynamic range with a constant voltage drop. The introduced pass element consists of a capacitor and...
Fuzzy adaptive sliding mode control for a class of uncertain nonlinear MIMO systems with application to a 2DOF twin propeller
, Article Lecture Notes in Artificial Intelligence (Subseries of Lecture Notes in Computer Science) ; Vol. 2715 , 2003 , Pages 500-507 ; ISSN: 03029743 ; Bolandhemat, H ; Tehrani, N.D ; Sharif University of Technology
2003
Abstract
A practical design method is presented which used the fuzzy logic advantages in adaptation of sliding mode control. The combined Fuzzy Adaptive Sliding Control (FASC) is designed in such a way to enhance satisfactory sliding performance and robustness with good level of chattering alleviation. The design approach is valid for a class of nonlinear uncertain MIMO systems. This control algorithm does not require the system model. A supervisory term is appended to the controller to assure the stability of fuzzy sliding mode control through Lyapunov theory. The design approach has been applied to a 2DOF twin propeler system with large uncertainty. Simulation results verified effectiveness of...
Design & implementation of a high precision & high dynamic range power consumption measurement system for smart energy IoT applications
, Article Measurement: Journal of the International Measurement Confederation ; Volume 146 , 2019 , Pages 458-466 ; 02632241 (ISSN) ; Atarodi, S. M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Internet of Things (IoT) devices have strict necessity for power consumption in order to achieve expected battery life. IoT nodes feature extreme power consumption range over 100 dB, between their operating modes. The main focus of this paper is to design and implement a high precision, high dynamic range, low power, and flexible power measurement system, which can be applied to different applications. The proposed system consists of a voltage regulating control loop, zero offset amplifiers, high precision analog to digital converters, and reference voltage. The proper operation of the proposed circuit are verified numerically with simulations and experimental measurements. The implemented...
Non-saturation mode analysis of IEEE 802.11 MAC protocol
, Article 18th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC'07, Athens, 3 September 2007 through 7 September 2007 ; December , 2007 ; 1424411440 (ISBN); 9781424411443 (ISBN) ; Ashtiani, F ; Tehrani, P ; Sharif University of Technology
2007
Abstract
In this paper, we propose a new modeling approach for analytical evaluation of normalized throughput and average backoff time for IEEE 802.11 MAC standard in non-saturation mode and with Poisson arrivals. To this end, we map different stages of distributed coordinated function (DCF) onto different components of a closed multi-class BCMP queueing network with arbitrary service time distribution. At the last part of the paper, we illustrate the applicability of the proposed approach by some numerical results in both saturation and non-saturation modes and obtain average backoff time for different arrival rates. © 2007 IEEE
Optimizing High Dynamic Range Current Measurement Circuit for IoT Applications
, Article 2023 5th Iranian International Conference on Microelectronics, IICM 2023 ; 2023 , Pages 211-215 ; 979-835036019-6 (ISBN) ; Atarodi, S. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
The power consumption of Internet-of-Things (IoT) devices is a major concern as it directly affects battery life. Therefore, measuring and monitoring the energy usage of IoT devices is vital. However, measuring the current consumption measurement of IoT devices is challenging as it must cover a wide range with low power consumption. In this paper, an improved design for the current measurement circuit is presented. The pass element which is placed in the current path to measure the current based on the charge and discharge of the capacitor is optimized to have reduced voltage drop, lower power consumption, decreased costs, and improved integration with IoT devices. The proposed circuit is...