Loading...
Search for: safdari--f
0.095 seconds

    An innovative isolated bidirectional soft-switched battery charger for plug-in hybrid electric vehicle

    , Article International Review on Modelling and Simulations ; Volume 6, Issue 6 , 2013 , Pages 1739-1745 ; 19749821 (ISSN) Ebrahimi, S ; Khazaeli, F ; Tahami, F ; Oraee, H ; Sharif University of Technology
    Praise Worthy Prize S.r.l  2013
    Abstract
    Plug-In hybrid electric vehicles could be connected to the electrical grid to be recharged. To ease the charging process, one solution could use an on-board charger to charge the electric vehicle battery. This charger should be able to be connected to a conventional outlet for convenience reasons and moreover, it should be a grid friendly charger in order not to pollute the electrical network. Since most of the electric vehicle related projects are at their initial phases, keeping up with the pace and developing new technologies and proposing innovations and concepts will help growing the industry. In this regard, a new integrated bidirectional isolated soft-switched plug-in hybrid electric... 

    A multiscale phase field method for joint segmentation-rigid registration application to motion estimation of human knee joint

    , Article Biomedical Engineering - Applications, Basis and Communications ; Volume 23, Issue 6 , 2011 , Pages 445-456 ; 10162372 (ISSN) Eslami, A ; Esfandiarpour, F ; Shakourirad, A ; Farahmand, F ; Sharif University of Technology
    2011
    Abstract
    Image based registration of rigid objects has been frequently addressed in the literature to obtain an object's motion parameters. In this paper, a new approach of joint segmentation-rigid registration, within the variational framework of the phase field approximation of the Mumford-Shah's functional, is proposed. The defined functional consists of two Mumford-Shah equations, extracting the discontinuity set of the reference and target images due to a rigid spatial transformation. Multiscale minimization of the proposed functional after finite element discretization provided a sub-pixel, robust algorithm for edge extraction as well as edge based rigid registration. The implementation... 

    Influence of material and geometry of the dielectric on the characteristics of the tank circuit resonators for high-Tc RF-SQUID-based system

    , Article IEEE Transactions on Applied Superconductivity ; Volume 26, Issue 3 , 2016 ; 10518223 (ISSN) Kalantari, N ; Shanehsazzadeh, F ; Sarreshtedari, F ; Fardmanesh, M ; Sharif University of Technology
    2016
    Abstract
    Characteristics of a lumped element L-C tank circuit resonator of high-Tc rf-SQUIDs, which plays an important role in the device operation, have been experimentally investigated, according to the corresponding simulations obtained by COMSOL Multiphysics. We experimentally investigated the characteristics of the resonators by measuring their scattering parameters, as well as evaluating the rf-SQUID signal. Our SQUIDs are made of sputtered YBCO thin films with 3-mm-diameter washer areas. Different configurations of the resonator are investigated, and it is observed that, by increasing the thickness of the dielectric in a specific range, the reflection coefficient (S11) increases. For the... 

    Optimisation of deep mixing technique by artificial neural network based on laboratory and field experiments

    , Article Georisk ; 2019 ; 17499518 (ISSN) Ahmadi Hosseini, A ; Mojtahedi, F. F ; Sadeghi, H ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    Abstract
    Ground improvement techniques are inevitable for weak soils that cannot endure the design load imposed by superstructures. Deep mixing technique (DMT) as one of these methods is promising and effective when a deep soil layer with low bearing capacity is encountered. Such deposits are quite common in the South-west of Iran where the studied site is located. In order to validate the influence of DMT on the enhancement of strength, both in-situ and laboratory tests were conducted. Afterwards, a parametric study was carried out to investigate the influence of key factors including cement content, water–cement ratio, curing time and plasticity index (PI) on the performance of DMT. In summary, a... 

    A new study in designing MTMDs in SDOF and MDOF systems based on the spectral analysis method

    , Article Earthquake and Structures ; Volume 19, Issue 4 , 2020 , Pages 243-259 Baigoly, M ; Shargh, F. H ; Rofooei, F. R ; Sharif University of Technology
    Techno-Press  2020
    Abstract
    This study aims to optimize, design, and predict the MTMDs performance in SDOF systems using spectral analysis, and then apply their results to MDOF structures. Given the importance of spectral analysis in the design of new engineering structures, achieving a method for designing TMDs based on this theory can be of great importance for structural designers. In this study, several convenient combinations of MTMDs in an SDOF system are first considered to minimize the maximum displacement. For calculating the frequency ratios of dampers, an innovative technique is adopted in which the values of different modal responses obtained from the spectral analysis are approached together. This... 

    Methanol-to-hydrocarbons product distribution over sapo-34 and zsm-5 catalysts: The applicability of thermodynamic equilibrium and anderson-schulz-flory distribution

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 38, Issue 2 , 2019 , Pages 49-59 ; 10219986 (ISSN) Sahebdelfar, S ; Yaripour, F ; Ahmadpour, S ; Khorasheh, F ; Sharif University of Technology
    Iranian Institute of Research and Development in Chemical Industries  2019
    Abstract
    The product distribution of methanol to hydrocarbons conversion over SAPO-34 and ZSM-5 catalysts was studied using thermodynamic equilibrium and Anderson-Schulz-Flory (ASF) distributions. The equilibrium compositions were calculated using constrained Gibbs free energy minimization. The effect of catalyst type was considered by setting upper limits to product carbon number due to shape selectivity according to zeotype catalyst channel size; that is, n5 for SAPO-34 but n6 for aliphatic and n10 for aromatic compounds over H-ZSM-5 catalyst. The equilibrium selectivity of kinds of paraffin is negligible over SAPO-34 system while that of olefins is very small over H-ZSM-5, both in agreement... 

    Shielding factor enhancement method for bi-stage active shield in SQUID-based magnetocardiography system

    , Article 29th Iranian Conference on Electrical Engineering, ICEE 2021, 18 May 2021 through 20 May 2021 ; 2021 , Pages 129-133 ; 9781665433655 (ISBN) Alipour, Z ; Esmaeili, F ; Shanehsazzadeh, F ; Fardmanesh, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    We proposed a simple method to enhance shielding factor of our previously proposed bi-stage active shield system employed in a SQUID-based magnetocardiography system. The additional proposed design is optimized for canceling the power-line magnetic interference field to provide a calmer magnetic environment for the bi-stage active shield. A 50 Hz cancellation coil is placed around the bi-stage shielding system which includes inner and outer coils designed for compensating low-frequency (0-0.1Hz) and high-frequency (0.1-100Hz) environmental magnetic noise, respectively. In this configuration, a SQUID magnetometer is located at the center of these coils. Considering that the power-line... 

    Shielding factor enhancement method for Bi-stage active shield in SQUID-based magnetocardiography system

    , Article 29th Iranian Conference on Electrical Engineering, ICEE 2021, 18 May 2021 through 20 May 2021 ; 2021 , Pages 129-133 ; 9781665433655 (ISBN) Alipour, Z ; Esmaeili, F ; Shanehsazzadeh, F ; Fardmanesh, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    We proposed a simple method to enhance shielding factor of our previously proposed bi-stage active shield system employed in a SQUID-based magnetocardiography system. The additional proposed design is optimized for canceling the power-line magnetic interference field to provide a calmer magnetic environment for the bi-stage active shield. A 50 Hz cancellation coil is placed around the bi-stage shielding system which includes inner and outer coils designed for compensating low-frequency (0-0.1Hz) and high-frequency (0.1-100Hz) environmental magnetic noise, respectively. In this configuration, a SQUID magnetometer is located at the center of these coils. Considering that the power-line... 

    Physical and hydraulic properties of a new spring packing

    , Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) Mafi, M ; Yazdani, F ; Farhadi, F ; Deldari, H ; Sharif University of Technology
    2006
    Abstract
    Physical and hydraulic properties of new stainless steel spring packing are introduced. The measured hydraulic properties are: dry and wetted packed bed pressure drop, loading and flooding points and the liquid holdups. The appropriate coefficients for predicting the mentioned hydraulic properties from different correlations are also reported. Hydraulic properties for this packing are compared with available packings. In spite of small size, the dry and wetted packed bed pressure drops of spring packing are less than similar Raschig and Protruded rings. The total liquid holdup of this packing is greater than other commercial packings. The big total liquid holdup and physical surface area are... 

    Blind modal identification of non-classically damped systems from free or ambient vibration records

    , Article Earthquake Spectra ; Volume 29, Issue 4 , 2013 , Pages 1137-1157 ; 87552930 (ISSN) Abazarsa, F ; Nateghi, F ; Ghahari, S. F ; Taciroglu, E ; Sharif University of Technology
    2013
    Abstract
    A significant segment of system identification literature on civil structures is devoted to response-only identification, simply because lack of measurements of input excitations for civil structures is a fairly common scenario. In recent years, several researchers have successfully adapted a second-order blind identification (SOBI) technique-a method originally developed for "blind source separation" of audio signals-to response-only identification of mechanical and civil structures. However, this development had been confined to fully instrumented classically damped systems. While several approaches have been proposed recently for extending SOBI to non-classically damped systems, they all... 

    Catalytic effect of copper oxide on H2S sensing properties of nanostructured WO3

    , Article Sensor Letters ; Volume 11, Issue 11 , 2013 , Pages 2015-2020 ; 1546198X (ISSN) Nowrouzi, R ; Razi, F ; Rahimi, F ; Zad, A. I ; Sharif University of Technology
    American Scientific Publishers  2013
    Abstract
    Cuprous oxide powder was added to WO3 sol as a catalyst and the composite sol was deposited on alumina substrates by spin coating process and annealing at 500 °C for 1 hour. Sensing properties of the pure and doped tungsten oxide samples to H2S gas were analyzed. WO 3-Cu2O (1%) samples showed good sensitivity towards 250 ppb of the gas at 100 °C and 1 ppm at room temperature (25 °C). Crystal structure, morphology and chemical composition of the sample were studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDAX) analyses and X-ray photoelectron spectroscopy (XPS). Based on these data, possible reaction mechanisms of hydrogen sulfide over WO... 

    Response-only modal identification of structures using limited sensors

    , Article Structural Control and Health Monitoring ; Volume 20, Issue 6 , 2013 , Pages 987-1006 ; 15452255 (ISSN) Abazarsa, F ; Ghahari, S. F ; Nateghi, F ; Taciroglu, E ; Sharif University of Technology
    2013
    Abstract
    Herein, we propose a method based on the existing second-order blind identification of underdetermined mixtures technique for identifying the modal characteristics - namely, natural frequencies, damping ratio, and real-valued partial mode shapes of all contributing modes - of structures with a limited number of sensors from recorded free/ambient vibration data. In the second-order blind identification approach, second-order statistics of recorded signals are used to recover modal coordinates and mode shapes. Conventional versions of this approach require the number of sensors to be equal to or greater than the number of active modes. In the present study, we first employ a parallel factor... 

    Comparative investigation of low and high frequency pulse tube regenerators

    , Article Scientia Iranica ; Volume 18, Issue 2 B , April , 2011 , Pages 205-212 ; 10263098 (ISSN) Jafarian, A ; Roshanghalb, F ; Saidi, M. H ; Imanimehr, F ; Sharif University of Technology
    2011
    Abstract
    The objective of the present work is to compare the performance of the regenerator of pulse tube refrigerators at low and high frequencies. The hydrodynamic and thermal behavior of the regenerator is investigated in this respect. To consider the system performance, a system of conservation equations including two energy equations for the regenerator as a porous media is employed. The present model considers one-dimensional, periodic, unsteady, compressible flow in the regenerator. The conservation equations are transformed by implementing the volumetric average scheme. The method of harmonic approximation is employed to derive an analytical solution. To explore the system performance, net... 

    The effect of viscosity, applied frequency and driven pressure on the laser induced bubble luminescence in water-sulfuric acid mixtures

    , Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 380, Issues 27–28 , June , 2016 , Pages 2219–2226 ; 03759601 (ISSN) Sadighi Bonabi, R ; Alijan Farzad Lahiji, F ; Razeghi, F ; Sharif University of Technology
    Elsevier  2016
    Abstract
    Production and oscillation of sonoluminescence bubbles by laser pulse in the presence of acoustic field in water and different concentrations of sulfuric acid are investigated. In the presence of acoustic field, the laser causes variable speed of sound, surface tension and density; and the host liquid acts as a compressible one and strongly affects the bubble's dynamics equations. The effect of various concentrations of sulfuric acid as a host liquid on the oscillation of bubble radius, bubble wall velocity and bubble interior temperature is studied. Furthermore, the effect of applied frequency on LI-SCBL in the presence of the acoustic field is investigated and an optimum sound wave... 

    Frozen leg operation of a three-phase dual active bridge DC/DC converter at light loads

    , Article Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC ; Volume 2018-March , 18 April , 2018 , Pages 3385-3391 ; 9781538611807 (ISBN) Haghbin, S ; Blaabjerg, F ; Yazdani, F ; Bahman, A. S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    A three-phase dual active bridge (DAB) converter is designed and constructed as the DC/DC stage of a 50 kW fast charger station. Recently introduced 300A SiC power modules and drivers are utilized in the converter to obtain a high efficiency. Each module has two interconnected switches with anti-parallel diodes resembling a converter leg. It is observed that the driver halts the module operation as a result of protective actions such as over-current, gate under-voltage, or gate overvoltage. In such case the module operates as a leg with two diodes until an external hardware signal resets the driver. The aim of this paper is to provide analysis, simulation and experiments for a three-phase... 

    NLOS identification in range-based source localization: statistical approach

    , Article IEEE Sensors Journal ; Volume 18, Issue 9 , 1 May , 2018 , Pages 3745-3751 ; 1530437X (ISSN) Abolfathi Momtaz, A ; Behnia, F ; Amiri, R ; Marvasti, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    Least squares estimation is a widely-used technique for range-based source localization, which obtains the most probable position of mobile station. These methods cannot provide desirable accuracy in the case with a non line of sight (NLOS) path between mobile station and base stations. To circumvent this drawback, many algorithms have been proposed to identify and mitigate this error; however, they have a large run-time overhead. On the other hand, new positioning systems utilize a large set of base stations, and a practical algorithm should be fast enough to deal with them. In this paper, we propose a novel algorithm based on subspace method to identify and eliminate the NLOS error.... 

    Failure mode, effects and criticality analysis (FMECA) in power electronic based power systems

    , Article 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, 3 September 2019 through 5 September 2019 ; 2019 ; 9789075815313 (ISBN) Peyghami, S ; Davari, P ; F. Firuzabad, M ; Blaabjerg, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Power electronics is becoming an underpinning technology for modern power systems. Power converters are increasingly used in various applications implying different levels of importance in power systems. Hence, optimal decision-making for manufacturing, control, operation and maintenance of them requires understanding of their importance in the power systems. Furthermore, identifying the converters importance may be beneficial for simplifying the system-level reliability modeling in a large Power Electronic based Power Systems (PEPSs). Thereby, a Failure Mode, Effects and Criticality Analysis (FMECA) approach is proposed in this paper in order to figure out the importance of converters in... 

    Effect of soil types on the dynamic response of an embedded pipe in a typical slope

    , Article 7th International Conference on Earthquake Geotechnical Engineering, ICEGE 2019, 17 January 2019 through 20 January 2019 ; 2019 , Pages 2316-2324 ; 9780367143282 (ISBN) Farahi Jahromi, H ; Jafarzadeh, F ; Silvestri F ; Moraci N ; Sharif University of Technology
    CRC Press/Balkema  2019
    Abstract
    The land-sliding forces applied to buried pipelines depend on the ground condition, types of loading and pipelines features. This paper intends to numerically investigate the effect of ground condition on pipelines. The loading type and pipeline features are kept constant. The pipeline which is positioned at mid-length of the slope, is made of steel and intersects the slope at the angle of 90o. The slope material specifications are determined based on geotechnical reports andthe harmonic loading simulates a 7.5 magnitude earthquake. The descending trend of slope displacement in sandy clay, loose to medium sand, cemented sand and medium to hard clayare shown by numerical calculations. But,... 

    Inhibitory effects of functionalized indium doped ZnO nanoparticles on algal growth for preservation of adobe mud and earthen-made artworks under humid conditions

    , Article International Biodeterioration and Biodegradation ; Volume 127 , Febraury , 2018 , Pages 209-216 ; 09648305 (ISSN) Shariati, M ; Mallakin, A ; Malekmohammady, F ; Khosravi Nejad, F ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    In this article, indium doped ZnO nanoparticles (alloy nanoparticles) were investigated as inhibitors against algae growth on adobe mud and earthen artworks for surface preservation from destruction caused by micro-organisms under humid conditions, through surface modification and activation run off. Nanoparticles (NPs) were fabricated by physical vapor deposition (PVD) growth mechanism. The fabricated NPs were approximately 20 nm in size. The Chlorella vulgaris and Scenedesmus quadricauda were tested by application of indium doped ZnO nanoparticles (In/ZnO NPs) as inhibitors. As concentrations of NPs increased, the negative impacts of NPs on the algal growth were enhanced and physical... 

    Effect of soil types on the dynamic response of an embedded pipe in a typical slope

    , Article 7th International Conference on Earthquake Geotechnical Engineering, ICEGE 2019, 17 January 2019 through 20 January 2019 ; 2019 , Pages 2316-2324 ; 9780367143282 (ISBN) Farahi Jahromi, H ; Jafarzadeh, F ; Silvestri F ; Moraci N ; Sharif University of Technology
    CRC Press/Balkema  2019
    Abstract
    The land-sliding forces applied to buried pipelines depend on the ground condition, types of loading and pipelines features. This paper intends to numerically investigate the effect of ground condition on pipelines. The loading type and pipeline features are kept constant. The pipeline which is positioned at mid-length of the slope, is made of steel and intersects the slope at the angle of 90o. The slope material specifications are determined based on geotechnical reports andthe harmonic loading simulates a 7.5 magnitude earthquake. The descending trend of slope displacement in sandy clay, loose to medium sand, cemented sand and medium to hard clayare shown by numerical calculations. But,...