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Total 327 records

    Use of gas chromatography-mass spectrometry combined with resolution methods to characterize the essential oil components of Iranian cumin and caraway

    , Article Journal of Chromatography A ; Volume 1143, Issue 1-2 , 2007 , Pages 215-226 ; 00219673 (ISSN) Jalali Heravi, M ; Zekavat, B ; Sereshti, H ; Sharif University of Technology
    2007
    Abstract
    Gas chromatography-mass spectrometry combined with iterative and non-iterative resolution methods was used to characterize the essential oil components of Iranian cumin and caraway. Orthogonal projection resolution (OPR) as a non-iterative and distance-selection-multivariate curve resolution-alternative least squares (DS-MCR-ALS) as an iterative method were used as auxiliary means to the analysis in the case of overlapping peaks. A total of 19 and 39 components were identified by direct similarity searches for cumin and caraway oils, respectively. These numbers were extended to 49 and 98 components, respectively with the help of chemometric techniques. Major constituents in cumin are... 

    Maximizing the secrecy energy efficiency of the cooperative rate-splitting aided downlink in multi-carrier uav networks

    , Article IEEE Transactions on Vehicular Technology ; Volume 71, Issue 11 , 2022 , Pages 11803-11819 ; 00189545 (ISSN) Bastami, H ; Moradikia, M ; Abdelhadi, A ; Behroozi, H ; Clerckx, B ; Hanzo, L ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2022
    Abstract
    Although Unmanned Aerial Vehicles (UAVs) are capable of significantly improving the information security by detecting the eavesdropper's location, their limited energy motivates our research to propose a secure and energy efficient scheme. Thanks to the common-message philosophy introduced by Rate-Splitting (RS), we no longer have to allocate a portion of the transmit power to radiate Artificial Noise (AN), and yet both the Energy Efficiency (EE) and secrecy can be improved. Hence we define and study the Secrecy Energy Efficiency (SEE) of a multi-carrier multi-UAV network, in which Cooperative Rate-Splitting (CRS) is employed by each multi-antenna UAV Base-Station (UAV-BS) for protecting... 

    Winding function model for predicting performance of 2-DOF wound rotor resolver

    , Article IEEE Transactions on Transportation Electrification ; Volume 8, Issue 2 , 2022 , Pages 2062-2069 ; 23327782 (ISSN) Zare, F ; Nasiri Gheidari, Z ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2022
    Abstract
    Two-degree-of-freedom (2-DOF) electrical machines require position sensors for their motion control. In comparison with using two independent sensors, using a 2-DOF sensor enhances the closed-loop control system's performance. However, due to the 3-D structure of the 2-DOF sensor, its performance evaluation needs 3-D analysis. Also, due to helical motion the accuracy deterioration of the sensor, under mechanical faults needs more attention. Although the finite element method (FEM) is the best way to simulate such sensors, most of the commercial packages for transient finite element simulations are not able to consider two separate motions simultaneously. Furthermore, FEM has a high... 

    Joint multi-user interference and clipping noise cancellation in uplink MC-CDMA system

    , Article AEU - International Journal of Electronics and Communications ; Volume 64, Issue 5 , 2010 , Pages 425-432 ; 14348411 (ISSN) AliHemmati, R ; Azmi, P ; Marvasti, F ; Sharif University of Technology
    Abstract
    In this paper, an iterative method is proposed to jointly cancel multi-user interference and clipping noise in uplink Multi-Carrier Code Division Multiple Access (MC-CDMA) systems. Clipping is the simplest method to overcome high peak-to-average power ratio of multi-carrier signals but it makes the signals distorted. Reconstruction methods use non-distorted samples to reconstruct distorted samples in the receiver but multi-user interference causes the methods do not work properly because all the received samples are distorted due to clipping and interference and so there is no undistorted samples to be used in recovering clipped samples. On the other hand, multi-user interference... 

    Assessment of sustainable groundwater resources management using integrated environmental index: Case studies across Iran

    , Article Science of the Total Environment ; Volume 676 , 2019 , Pages 792-810 ; 00489697 (ISSN) Hosseini, S. M ; Parizi, E ; Ataie Ashtiani, B ; Simmons, C. T ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    Assessing environmentally sustainable GW management (ESGM) needs a deep knowledge of the present and the projected status of GW (GW) quantity and quality. Translations of these data into policy relevant information are usually done through quantitative indices. Despite the availability of a dozen GW sustainability indicators, defining an integrated index based on internationally accepted scientific standards indicators is required. To fill this gap, an in-depth review on the developed indicators/index for evaluation of GW sustainable management (GWSM) from an environmental viewpoint at aquifer scales is provided in this study. Thirteen environmentally related quantitative indicators are... 

    Structured multiblock body-fitted grids solution of transient inverse heat conduction problems in an arbitrary geometry

    , Article Numerical Heat Transfer, Part B: Fundamentals ; Volume 54, Issue 3 , July , 2008 , Pages 260-290 ; 10407790 (ISSN) Azimi, A ; Kazemzadeh Hannani, S ; Farhanieh, B ; Sharif University of Technology
    2008
    Abstract
    The aim of this study is to develop iterative regularization algorithms based on parameter and function estimation techniques to solve two-dimensional/axisymmetric transient inverse heat conduction problems in curvilinear coordinate system. The multiblock method is used for geometric decomposition of the physical domain into regions with patched-overlapped interface grids. The central finite-difference version of the alternating-direction implicit technique together with structured body-fitted grids is implemented for numerical solution of the direct problem and other partial differential equations derived by inverse analysis. The approach of estimating unknown parameters and functions is... 

    Nonlinear aeroelastic response of slender wings based on Wagner function

    , Article Thin-Walled Structures ; Volume 46, Issue 11 , 2008 , Pages 1192-1203 ; 02638231 (ISSN) Shams, Sh ; Sadr Lahidjani, M. H ; Haddadpour, H ; Sharif University of Technology
    2008
    Abstract
    This paper presents a method for nonlinear aeroelastic analysis of Human Powered Aircraft (HPA) wings. In this type of aircraft there is a long, highly flexible wing. Wing flexibility, coupled with long wing span can lead to large deflections during normal flight operation; therefore, a wing in vertical and torsional motion using the second-order form of nonlinear general flexible Euler-Bernoulli beam equations is used for structural modeling. Unsteady linear aerodynamic theory based on Wagner function is used for determination of aerodynamic loading on the wing. Combining these two types of formulations yields the nonlinear integro-differentials aeroelastic equations. Using the Galerkin's...