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    Development of high-resolution emission inventory to study the relative contribution of a local power plant to criteria air pollutants and Greenhouse gases

    , Article Urban Climate ; Volume 38 , 2021 ; 22120955 (ISSN) Shahbazi, H ; Abolmaali, A. M ; Alizadeh, H ; Salavati, H ; Zokaei, H ; Zandavi, R ; Torbatian, S ; Yazgi, D ; Hosseini, V ; Sharif University of Technology
    Elsevier B.V  2021
    Electrification of energy systems, including an increased percentage of electric vehicles on the road, is one of the primary paths to achieve zero carbon emissions. However, a reduced share of fossil fuel in transportation and industry requires a significant shift in power generation energy sources. Power generation from renewable sources is still limited and will be for the foreseeable future. Developing countries and oil-producing nations in the middle east may shift to electric vehicles, but electricity energy sources will not be easily moved to renewables., A detailed and comprehensive emission inventory was developed in a bottom-up method for a typical populated city in Iran,... 

    A novel method in adaptive image enlargement

    , Article Eurasip Journal on Advances in Signal Processing ; Volume 2012, Issue 1 , 2012 ; 16876172 (ISSN) Bayat, M ; Kafaie, G ; Ayremlou, A ; Marvasti, F ; Sharif University of Technology
    This article introduces a new adaptive method for image interpolation. In order to obtain a high resolution (HR) image from its low resolution (LR) counterpart (original image), an interpolator function (array) is used, and the main focus of this manuscript is to formulate and define this function. By applying this interpolator function to each row and column of a LR image, it is possible to construct its HR counterpart. One of the main challenges of image interpolation algorithms is to maintain the edge structures while developing an HR image from the LR replica. The proposed approach overcomes this challenge and exhibits remarkable results at the image edges. The peak signal to noise ratio... 

    High resolution DOA estimation in fully coherent environments

    , Article Progress In Electromagnetics Research C ; Volume 5 , 2008 , Pages 135-148 ; 19378718 (ISSN) Shahi, S. N ; Emadi, M ; Sadeghi, K ; Sharif University of Technology
    Electromagnetics Academy  2008
    A novel method for direction-of-arrival (DOA) estimation is proposed. This technique employs the excellent performance of Bartlett method in coherent environments as well as high resolution and low computational complexity of Beamspace MUSIC. Simulation results show that the use of Beamspace MUSIC with Bartlett yields significantly improved performance compared to the original MUSIC especially in highly correlated situations. © 2008, Electromagnetics Academy. All rights reserved  

    Development of Gamma Spectroscopy Software for Analysis of High Resolution Detectors

    , M.Sc. Thesis Sharif University of Technology Jamshidi, Vahid (Author) ; Sohrabpur, Mostafa (Supervisor)
    Gamma-ray spectroscopy is the quantitative study of the energy spectra of gamma-ray sources. A gamma-ray spectrometer also determines the energies of the gamma-rays photons emitted by the source. A radioactive nucleus (radionuclide) commonly emits gamma rays in the energy range from a few keV to ~10 MeV, corresponding to the typical energy levels in nuclei with reasonably long lifetimes. Most radioactive sources produce gamma rays of various energies and intensities. When these emissions are collected and analyzed with a gamma-ray spectroscopy system, a gamma-ray energy spectrum can be produced. A detailed analysis of this spectrum is typically used to determine the identity and quantity of... 

    Radar HRRP modeling using dynamic system for radar target recognition

    , Article Radioengineering ; Vol. 23, issue. 1 , 2014 , p. 121-127 Aljorloo, A ; Hadavi, M ; Bastani, M. H ; Nayebi, M. M ; Sharif University of Technology
    High resolution range profile (HRRP) is being known as one of the most powerful tools for radar target recognition. The main problem with range profile for radar target recognition is its sensitivity to aspect angle. To overcome this problem, consecutive samples of HRRP were assumed to be identically independently distributed (IID) in small frames of aspect angles in most of the related works. Here, considering the physical circumstances of maneuver of an aerial target, we have proposed dynamic system which models the short dependency between consecutive samples of HRRP in segments of the whole HRRP sequence. Dynamic system (DS) is used to model the sequence of PCA (principal component... 

    A wide dynamic range low power 2× time amplifier using current subtraction scheme

    , Article 2016 IEEE International Symposium on Circuits and Systems, ISCAS 2016, 22 May 2016 through 25 May 2016 ; Volume 2016-July , 2016 , Pages 462-465 ; 02714310 (ISSN); 9781479953400 (ISBN) Molaei, H ; Khorami, A ; Hajsadeghi, K ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2016
    The most challenging issue of conventional Time Amplifiers (TAs) is their limited Dynamic Range (DR). This paper presents a mathematical analysis to clarify principle of operation of conventional 2× TA's. The mathematical derivations release strength reduction of the current sources of the TA is the simplest way to increase DR. Besides, a new technique is presented to expand the Dynamic Range (DR) of conventional 2× TAs. Proposed technique employs current subtraction in place of changing strength of current sources using conventional gain compensation methods, which results in more stable gain over a wider DR. The TA is simulated using Spectre-rf in TSMC 0.18um COMS technology. DR of the 2×... 

    High-resolution air temperature mapping in urban areas a review on different modelling techniques

    , Article Thermal Science ; Volume 21, Issue 6 , 2017 , Pages 2267-2286 ; 03549836 (ISSN) Taheri Shahraiyni, H ; Sodoudi, S ; Sharif University of Technology
    In this study, the importance of air temperature from different aspects (e. g., human and plant health, ecological and environmental processes, urban planning, and modelling) is presented in detail, and the major factors affecting air temperature in urban areas are introduced. Given the importance of air temperature, and the necessity of developing high-resolution spatio-temporal air-temperature maps, this paper categorizes the existing approaches for air temperature estimation into three categories (interpolation, regression, and simulation approaches) and reviews them. This paper focuses on high-resolution air temperature mapping in urban areas, which is difficult due to strong... 

    Application and performance comparison of high-resolution central schemes for the black oil model

    , Article International Journal of Numerical Methods for Heat and Fluid Flow ; Volume 17, Issue 7 , 2007 , Pages 736-753 ; 09615539 (ISSN) Naderan, H ; Taghizadeh Manzari, M ; Kazemzadeh Hannani, S ; Sharif University of Technology
    Purpose - The purpose of this paper is to investigate the performance of a specific class of high-resolution central schemes in conjunction with the black oil models for hydrocarbon reservoir simulation. Design/methodology/approach - A generalized black oil model is adopted, in which the solubility of gas in both oil and water and evaporation of oil are considered, leading to a system of equations prone to degeneracy. A computer code is generated and three test cases are solved to evaluate the performance of various schemes in terms of accuracy and discontinuity handling. Findings - It is shown that, although some of the central schemes are highly sensitive to the choice of... 

    Compositional Simulation of 1-D Oil Reservoirs Flow Using a High-Resolution Central Scheme

    , M.Sc. Thesis Sharif University of Technology Haghighi, Erfan (Author) ; Taghizadeh Manzari, Mehrdad (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor)
    In recent years, oil and gas reservoirs are one of the most valuable natural resources and are the main economical basis of the country. Therefore any research which can help to optimize the efficiency and enhance their recovery is of great importance. In the past 30 years, reservoir simulation has evolved from a research field to one of the most flexible tools in reservoir engineering. Simulation is usually more quick, cost effective and reliable than other methods in predicting reservoir performance. Because of complexity of the great amount of computations, research in oil reservoirs field is usually done by mathematical/computer programs, named as simulators. For this reason, various... 

    Empirical study on effect of surface texture and grain size on displacement measurement of optical flow sensors

    , Article 2014 2nd RSI/ISM International Conference on Robotics and Mechatronics, ICRoM 2014 ; Oct , 2014 , p. 493-497 ; ISBN: 9781479967438 Azizi, A ; Vossoughi, G ; Sharif University of Technology
    Although, the optical flow sensors which are used in optical mouse have high resolution in measuring displacement, their error refrain us from a precise and reliable measurement. Besides, these sensors require calibration based on the surface. Their error has different sources and the most important is surface texture in micro level. In this research, we have worked to find surface conditions on which sensor measurement is more precise. For this aim, we used an 800 DPI low cost optical flow sensor. For making different surface textures and grains, we printed different textures with 600 and 1200DPI resolution on white paper with certain length. Then we used optical flow sensor for measuring... 

    Statistical modeling of consecutive range profiles for radar target recognition

    , Article Proceedings International Radar Symposium, Dresden ; Volume 2 , June , 2013 , Pages 608-613 ; 21555753 (ISSN) ; 9783954042234 (ISBN) Ajorloo, A ; Hadavi, M ; Nayebi, M. M ; Bastani, M. H ; Sharif University of Technology
    The high resolution range profile (HRRP) is known as the most important tool in radar target recognition. Mainly, the sensitivity to the aspect angle limits the performance of the related methods. To overcome this problem, Gaussian mixture distribution is used to model the short-term relation of consecutive HRRPs. In this work, an alternative dynamical system based method is proposed to overcome the limitations of recent methods in the field such as the independency assumption. Here, the performance of the method is tested by the data produced in an electromagnetic simulation for the radar return from an aerial maneuvering target. The results show the performance of the proposed method... 

    A low power high resolution time to digital converter for ADPLL application

    , Article 59th IEEE International Midwest Symposium on Circuits and Systems, MWSCAS 2016, 16 October 2016 through 19 October 2016 ; 2017 ; 15483746 (ISSN); 9781509009169 (ISBN) Molaei, H ; Hajsadeghi, K ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2017
    A new nonlinear Time to Digital Converter (TDC) based on time difference amplification is the proposed. A new gain compensation method is presented to expand the DR of conventional × 2 Time Amplifiers (TAs). Instead of conventional gain compensation approach based on changing strength of current sources, the proposed technique uses current difference which results more stable gain over wider DR. In order to avoid two different paths of the stages, a sign bit detection part is the proposed at the front of the TDC to allow using one path of stages for both positive and negative input time differences. As a result, the most advantages of the proposed TDC are its high resolution, wide DR, and... 

    Design and fabrication of a new multi-loop saddle coil for 1.5 T MRI

    , Article Review of Scientific Instruments ; Volume 90, Issue 11 , 2019 ; 00346748 (ISSN) Parsa, J ; Mohammadzadeh, M ; Sharif University of Technology
    American Institute of Physics Inc  2019
    Radiofrequency coils provide high-resolution magnetic resonance (MR) imaging of human tissues. A small RF coil produces MR images with a higher resolution compared to the commercial volume MR coils from mass limited samples. Signal to noise ratio (SNR) plays a key role in the optimal design of receiver radiofrequency coils. In this work, we present a three-loop saddle coil suitable for MR imaging of digits of the human body. The geometry of the introduced coil is optimized to achieve the highest SNR. The coil performance is evaluated through comparing the measured SNR maps of the optimal coil derived from MR images of a saline phantom with the corresponding measured SNR maps of a commercial... 

    Numerical simulation using a modified solver within OpenFOAM for compressible viscous flows

    , Article European Journal of Computational Mechanics ; Volume 28, Issue 6 , 2020 , Pages 541-572 Ghazanfari, V ; Salehi, A. A ; Keshtkar, A ; Shadman, M. M ; Askari, M. H ; Sharif University of Technology
    River Publishers  2020
    In this work, we attempted to develop an Implicit Coupled Density-Based (ICDB) solver using LU-SGS algorithm based on the AUSM+ up scheme in OpenFOAM. Then sonicFoam solver was modified to include viscous dissipation in order to improve its capability to capture shock wave and aerothermal variables. The details of the ICDB solver as well as key implementation details of the viscous dissipation to energy equation were introduced. Finally, two benchmark tests of hypersonic airflow over a flat plate and a 2-D cylinder were simulated to show the accuracy of ICDB solver. To verify and validate the ICDB solver, the obtained results were compared with other published experimental data. It was... 

    Numerical solution of high-frequency oscillations of a gas column using a modified lax-wendroff scheme

    , Article International Conference on Noise and Vibration Engineering 2006, ISMA 2006, Heverlee, 18 September 2006 through 20 September 2006 ; Volume 4 , 2006 , Pages 2191-2199 Ghasemi, A ; Sharif University of Technology
    Katholieke Universiteit Leuven  2006
    Recently, several high-order accurate methods have been developed for solving nonlinear equations governing in the high-frequency oscillations of a fluid column. If we assume that the value of Reynolds and Prandtl numbers are high enough then it is possible to neglect the effect of Stokes Layer and it has been previously shown that the calculated pressure profile obtained by solving three-dimensional axisymmetric compressible NS (Navier-Stokes) equations is in good agreement with one-dimensional adiabatic model of Ilinskii. For this particular flow which is the typical of engineering flows inside acoustical compressors, it is clear that high-resolution simulation of NS equations in higher... 

    A high speed, high resolution, low voltage currentmode sample and hold

    , Article IEEE International Symposium on Circuits and Systems 2005, ISCAS 2005, Kobe, 23 May 2005 through 26 May 2005 ; 2005 , Pages 1417-1420 ; 02714310 (ISSN) Rajaee, O ; Bakhtiar, M. S ; Sharif University of Technology
    A low voltage current mode sample and hold (S/H) in 0.18μm technology with 1.5v supply voltage is presented. This S/H has 12-bit linearity, i.e., gain and nonlinearity errors of S/H are less than 0.02μA for 100uA input current. Maximum sampling rate for this structure is 100 MHz (using double sampling technique). © 2005 IEEE  

    A numerical comparative study of various flooding techniques in hydrocarbon reservoirs

    , Article Journal of Porous Media ; Volume 15, Issue 2 , 2012 , Pages 101-112 ; 1091028X (ISSN) Naderan, H ; Manzari, M. T ; Hannani, S. K ; Sharif University of Technology
    This paper investigates the efficiency and performance of several of the fiooding techniques popular in secondary and enhanced oil recovery. These processes include water fiooding, immiscible and miscible gas fiooding, and several forms of water-alternating-gas (WAG) injection. The study is carried out numerically on a typical one-dimensional domain using an advanced high-resolution central scheme. Some performance indices such as oil cut drop, breakthrough time, and sweep efficiency were employed to evaluate the appropriateness of each injection strategy  

    One-pot thermolysis synthesis of CuInS2 nanoparticles with chalcopyrite-wurtzite polytypism structure

    , Article Journal of Materials Science: Materials in Electronics ; Volume 26, Issue 11 , November , 2015 , Pages 8960-8972 ; 09574522 (ISSN) Vahidshad, Y ; Tahir, M. N ; Mirkazemi, S. M ; Iraji Zad, A ; Ghasemzadeh, R ; Tremel, W ; Sharif University of Technology
    Springer New York LLC  2015
    CuInS2 nanoparticles as the visible (wurtzite, 1.67 eV) or near infrared (chalcopyrite, 1.50 eV) light absorbing material in thin film solar cells, were synthesized using facile, one step heating up method by dissolving of CuCl, InCl3 and SC(NH2)2 as precursors in oleylamine (OLA) alone or in combination with oleic acid (OA) and 1-octadecene (ODE) as solvent. The phase, size, morphology, and size distribution were controlled by the coordination ability between solvent molecules and metal precursors, reaction temperature and time. The presence of higher amounts of thiourea or OA to OLA led to the formation of chalcopyrite phase in comparison to wurtzite structure. Also, higher reaction... 

    A low-power technique for high-resolution dynamic comparators

    , Article International Journal of Circuit Theory and Applications ; Volume 46, Issue 10 , 2018 , Pages 1777-1795 ; 00989886 (ISSN) Khorami, A ; Sharifkhani, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2018
    A low-power technique for high-resolution comparators is introduced. In this technique, p-type metal-oxide-semiconductor field-effect transistors are employed as the input of the latch of the comparator just like the input of the preamplifier. The latch and preamplifier stages are activated in a special pattern using an inverter-based controller. Unlike the conventional comparator, the preamplification delay can be set to an optimum low value even if after the preamplification, the output voltages is less than n-channel metal-oxide semiconductor voltage threshold. As a result, the proposed comparator reduces the power consumption significantly and enhances the speed. The speed and power... 

    Radar Target Recognition using High Resolution Range Profile

    , M.Sc. Thesis Sharif University of Technology Aghatabar Roodbary, Amin (Author) ; Bastani, Mohammad Hassan (Supervisor)
    One of the subsets of the radar systems is recognition of targets. Radar Target Recognition (RTR) is a process in which a target is distinguished from a set of targets. To recognize radar targets, we need to extract useful information from the returned signal from them. The most important issues in recognizing radar targets are the selection of information that reduces the amount of information needed for the identification process, the ease of extracting information from the moving target, and the ease of decision making to determine the identity of the target. One method is to produce a high resolution range profile, which is the one-dimensional image of the target in the direction of...