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    Experimental analysis of CO2, CO, SO2 and NO x emission factors of Iran's fossil fuel fired power plants

    , Article 2010 IEEE International Energy Conference and Exhibition, EnergyCon 2010, 18 December 2010 through 22 December 2010 ; 2010 , Pages 775-779 ; 9781424493807 (ISBN) Shahsavari Alavijeh, H ; Shahsavari Alavijeh, H ; Kiumarsi Oskuei, A ; Asheri, M. H ; Sharif University of Technology
    2010
    Abstract
    In this paper, the effect of different parameters of power plants, such as height above sea level, performance, ambient temperature, fuel type on emissions in Iran's power plants is investigated. Based on that, a general strategy for selecting the type of power plant, fuel that fit with the geographical situation in the Middle East is presented. Results taken from this scientific study shows that using natural gas to generate power in the region should be a priority. As well as expected, the value of various emission factors decrease by increasing power produce. Also the emission factors of combined cycle power plants are the lowest as compared to other types of power plants  

    Greenhouse gas emission measurement and economic analysis of Iran natural gas fired power plants

    , Article Energy Policy ; Volume 60 , 2013 , Pages 200-207 ; 03014215 (ISSN) Shahsavari Alavijeh, H ; Kiyoumarsioskouei, A ; Asheri, M. H ; Naemi, S ; Shahsavari Alavije, H ; Basirat Tabrizi, H ; Sharif University of Technology
    2013
    Abstract
    This study attempts to examine the natural gas fired power plants in Iran. The required data from natural gas fired power plants were gathered during 2008. The characteristics of thirty two gas turbine power plants and twenty steam power plants have been measured. Their emission factor values were then compared with the standards of Energy Protection Agency, Euro Union and World Bank. Emission factors of gas turbine and steam power plants show that gas turbine power plants have a better performance than steam power plants. For economic analysis, fuel consumption and environmental damages caused by the emitted pollutants are considered as cost functions; and electricity sales revenue are... 

    Investigation of scaling effects on fiber metal laminates under tensile and flexural loading

    , Article Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications ; Volume 229, Issue 3 , 2015 , Pages 189-201 ; 14644207 (ISSN) Haghi Kashani, M ; Sadighi, M ; Mohammadkhah, M ; Shahsavari Alavijeh, H ; Sharif University of Technology
    SAGE Publications Ltd  2015
    Abstract
    In this study, scaling effects on fiber metal laminates under tensile and three-point bending tests were investigated numerically and experimentally. The fiber metal laminate specimens were made of aluminum 1050 and unidirectional glass-epoxy. Two scaled sizes of specimens were prepared based on A1n, 0n=90n s. Some specified mechanical properties of these samples were investigated and results showed that fiber metal laminates obey scaling law under quasi-static loading. Explicit finite element code LS-DYNA was utilized for numerical simulation. After validating numerical simulation with experiments, scaling law was studied numerically for four different... 

    Biocompatibility and hyperthermia efficiency of sonochemically synthesized magnetic nanoparticles

    , Article SPIN ; Volume 9, Issue 2 , 2019 ; 20103247 (ISSN) Talebi, M ; Malaie Balasi, Z ; Ahadian, M. M ; Hatamie, S ; Shahsavari Alavijeh, M. H ; Ghafuri, H ; Sharif University of Technology
    World Scientific Publishing Co. Pte Ltd  2019
    Abstract
    Hereby, a sonochemical method for synthesis of pure magnetic Fe3O4Onanoparticles (Fe3O4-NPs) in large scale is being introduced. Synthesis proceeds via simple approach, at room temperature, under sonication, using cheap reagents, green antioxidant-reductant reagent and without using inert gas purge as protective atmosphere condition. During this procedure, hydrogen gas releases continuously as valuable byproduct at the anaerobic step of reaction. Characterizations' results indicate that the final product is pure spherical Fe3O4-NPs, with narrow size distribution and about less than 32nm in mean diameter while more than 99% of particles size were less than 40nm. According to Vibrational... 

    Speech activity detection using deep neural networks

    , Article 2017 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 1564-1568 ; 9781509059638 (ISBN) Shahsavari, S ; Sameti, H ; Hadian, H ; Sharif University of Technology
    2017
    Abstract
    In this paper, we introduce a new dataset for SAD and evaluate certain common methods such as GMM, DNN, and RNN on it. We have collected our dataset in a semi-supervised approach, using subtitled movies, with a labeling accuracy of 95%. This semi-automatic method can help us collect huge amounts of labeled audio data with very high diversity in language, speaker, and channel. We model the problem of SAD as a classification task to two classes of speech and non-speech. When using GMM for this problem, we use two separate mixtures to model speech and non-speech. In the case of neural networks, we use a softmax layer at the end of the network, with two neurons which represent speech and... 

    Biological hydrogen production by Enterobacter aerogenes: Structural analysis of treated rice straw and effect of substrate concentration

    , Article International Journal of Hydrogen Energy ; Volume 43, Issue 18 , 2018 , Pages 8718-8728 ; 03603199 (ISSN) Asadi, N ; Karimi Alavijeh, M ; Zilouei, H ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    The effect of organosolv pretreatment on the structure of rice straw was analyzed under different treatment severities and solvent concentrations. At higher severities, on account of a greater fragmentation of less crystalline parts, including amorphous cellulose, hemicellulose, and lignin, the severer the pretreatment was, the higher the crystallinity index became; however, changes in the index was less tangible with a severity factor lower than 3.3. At the low to mild pretreatment temperatures (120 °C and 150 °C), higher ethanol concentrations led to the lower crystallinity index. Despite an increasing trend of crystallinity index at harsh conditions, SEM images indicated the formation of... 

    Development of a mathematical methodology to investigate biohydrogen production from regional and national agricultural crop residues: A case study of Iran

    , Article International Journal of Hydrogen Energy ; Volume 42, Issue 4 , 2017 , Pages 1989-2007 ; 03603199 (ISSN) Asadi, N ; Karimi Alavijeh, M ; Zilouei, H ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    This study aims to construct a quantitative framework to assess biological production of hydrogen from agricultural residues in a country or region. The presented model is able to determine proper crops for biohydrogen production, its possible applications and use as well as environmental aspects. A multiplicative decomposition method was designed to forecast future production and Monte Carlo simulation was employed in the model to evaluate the risk of estimations. From 2013 to 2050, the hydrogen production capacity could increase from 53.59 to 164.41 kilotonnes (kt) in Iran. The highest contribution to biohydrogen production (52.1% in 2013 and 73.3% in 2050) belongs to cereal crops... 

    Effect of preweld microstructure on HAZ liquation cracking of rene 80 superalloy

    , Article Materials Science and Technology ; Volume 23, Issue 5 , 2007 , Pages 547-555 ; 02670836 (ISSN) Shahsavari, H. A ; Kokabi, A. H ; Nategh, S ; Sharif University of Technology
    2007
    Abstract
    The objective of this work was to study the microstructure of as cast, solution treated and overaged Rene 80 superalloy before and after welding treatment. Studies focused on identifying heat affected zone (HAZ) liquation cracking mechanism and the effect of preweld microstructure on it. The formation of HAZ liquation cracking or microfissuring is found to be strongly dependent on constitutional liquation of grain boundary precipitates. These liquated precipitates in the as cast state contain MC carbides and particularly γ/γ' eutectic islands. While in the overaged condition they consist of the MC carbides and borides. Also HAZ grain boundary liquation and subsequent resolidification occur... 

    Multi-quality of service routing and spectrum assignment in elastic optical networks

    , Article IEEE International Conference on Communications, 21 May 2017 through 25 May 2017 ; 2017 ; 15503607 (ISSN) ; 9781467389990 (ISBN) Shahsavari, S ; Beyranvand, H ; Salehi, J. A ; Sharif University of Technology
    2017
    Abstract
    In this paper, we investigate multi-quality of service (QoS) routing and spectrum assignment in elastic optical networks (EONs) by utilizing network state information in terms of bandwidth usage and holding time of established connections. Toward this aim, two types of traffic, namely big data traffic (BDT) requests, and fixed rate flow requests (FLRs) are considered, where BDTs can tolerate a pre-determined initial delay while FLRs must be served immediately without any delay. We assume that both frequency and time usage of optical bandwidth is slotted, and accordingly optical resources are defined in a two-dimensional (2D) time/frequency domain, where the smallest resource is specified... 

    Large eddy simulations of unconfined non-reacting and reacting turbulent low swirl jets

    , Article Flow, Turbulence and Combustion ; Volume 98, Issue 3 , 2017 , Pages 817-840 ; 13866184 (ISSN) Shahsavari, M ; Farshchi, M ; Arabnejad, M. H ; Sharif University of Technology
    Springer Netherlands  2017
    Abstract
    The low swirl flow is a novel method for stabilizing lean premixed combustion to achieve low emissions of nitrogen oxides. Understanding the characteristics of low swirl flows is of both practical and fundamental interest. In this paper, in order to gain better insight into low swirl stabilized combustion, large eddy simulation and dynamically thickened flame combustion modeling are used to characterize various features of non-reacting and reacting low swirl flows including vortex breakdown, shear layers’ instability, and coherent structures. Furthermore, four test cases with different equivalence ratios are studied to evaluate the effects of equivalence ratio on the flame and flow... 

    Joint cell muting and user scheduling in multicell networks with temporal fairness

    , Article Wireless Communications and Mobile Computing ; Volume 2018 , 2018 ; 15308669 (ISSN) Shahsavari, S ; Akar, N ; Khalaj, B. H ; Sharif University of Technology
    Hindawi Limited  2018
    Abstract
    A semicentralized joint cell muting and user scheduling scheme for interference coordination in a multicell network is proposed under two different temporal fairness criteria. In the proposed scheme, at a decision instant, each base station (BS) in the multicell network employs a cell-level scheduler to nominate one user for each of its inner and outer sections and their available transmission rates to a network-level scheduler which then computes the potential overall transmission rate for each muting pattern. Subsequently, the network-level scheduler selects one pattern to unmute, out of all the available patterns. This decision is shared with all cell-level schedulers which then forward... 

    DNA binding and recognition of a CC mismatch in a DNA duplex by water-soluble peptidocalix[4]arenes: synthesis and applications

    , Article Organic Letters ; Volume 18, Issue 19 , 2016 , Pages 4766-4769 ; 15237060 (ISSN) Alavijeh, N. S ; Zadmard, R ; Balalaie, S ; Alavijeh, M. S ; Soltani, N ; Sharif University of Technology
    American Chemical Society  2016
    Abstract
    Water-soluble peptidocalix[4]arenes were synthesized by the introduction of arginine-rich narrow groove-binding residues at lower rims through solid-phase synthesis. The study of binding of these water-soluble bidentate ligands to well-matched and mismatched DNA duplexes by fluorescent titrations, ethidium bromide (EB) displacement assays, DNA-melting experiments, and circular dichroism (CD) analysis revealed a sequence-dependent groove-binding mechanism  

    Numerical anaysis of a thermopneumatic micropump

    , Article ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels Collocated with 3rd Joint US-European Fluids Engineering Summer Meeting, ICNMM2010, 1 August 2010 through 5 August 2010, Montreal, QC ; 2010 , Pages 1135-1140 ; 9780791854501 (ISBN) Shahsavari, S ; Shafii, M. B ; Saidi, M. H ; Sharif University of Technology
    2010
    Abstract
    Thermopneumatic micropump is one type of positive displacement micropump, which has many applications due to its relatively large stroke volume, low working voltage, and simple fabrication in microscale. In this paper, a numerical study of heat transfer and fluid flow in a valveless thermopneumatically driven micropump is presented. For rectifying the bidirectional flow, a nozzle and a diffuser are used as the inlet and outlet channels of the chamber. Since the fluid flow is induced by the motion of a diaphragm, the numerical simulation includes fluid structure interaction, which requires applying a dynamic mesh. The domain of solution is divided into two sections; the actuator unit, which... 

    Improving materials logistics plan in road construction projects using discrete event simulation

    , Article Engineering, Construction and Architectural Management ; Volume 28, Issue 10 , 2021 , Pages 3144-3163 ; 09699988 (ISSN) Alvanchi, A ; Baniassadi, F ; Shahsavari, M ; Kashani, H ; Sharif University of Technology
    Emerald Group Holdings Ltd  2021
    Abstract
    Purpose: Motivated by the high cost of material movements in road construction projects, past studies have used analytical methods to optimize materials logistics plans. A key shortcoming of these methods is their inability to capture the uncertain, dynamic and complex characteristics of the road construction material logistics. Failure to incorporate these characteristics can lead to sub-optimal results. The purpose of this study is to propose the use of discrete event simulation (DES) to address the existing shortfall. Design/methodology/approach: Despite the powerful capabilities of DES models in capturing the operational complexities of construction projects, they have not been... 

    Supercritical carbon dioxide utilization in drug delivery: Experimental study and modeling of paracetamol solubility

    , Article European Journal of Pharmaceutical Sciences ; Volume 177 , 2022 ; 09280987 (ISSN) Bagheri, H ; Notej, B ; Shahsavari, S ; Hashemipour, H ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    In the present study, the solubility of paracetamol in supercritical CO2 is measured at temperatures between 311 and 358 K and pressures between 95 and 265 bar. It was shown that the solubility of paracetamol through a static solubility measurement method was between 0.3055 × 10−6 to 16.3582 × 10−6 based on mole fraction. The obtained experimental solubility data revealed the direct effect of pressure on the paracetamol experimental data, while the temperature has a dual effect of both increasing and decreasing effect considering the shifting point known as crossover pressure which was measured to be around 110 bar for paracetamol. Besides, two theoretical approaches were applied to predict... 

    Homotopy perturbation method for unsteady motion of a single bubble in a highly viscous liquid

    , Article Chemical Engineering Communications ; 2020 Shahsavari, M ; Oshaghi, M. R ; Afshin, H ; Firoozabadi, B ; Sharif University of Technology
    Taylor and Francis Ltd  2020
    Abstract
    In this study, the dynamics of the accelerated and steady-state motion of a single bubble in a quiescent highly viscous Newtonian liquid was investigated theoretically and experimentally. The presented mathematical model was based on Newton's second law of motion and a balance of buoyancy, drag, history, and added-mass forces. Due to the presence of non-linear terms in the equation of motion, homotopy perturbation method was used as a powerful analytical method to calculate the velocity analytically. To obtain accurate results in the experiments, a high-speed camera was used to record the bubble motion from the moment of detachment to the time at which the terminal velocity is reached.... 

    Homotopy perturbation method for unsteady motion of a single bubble in a highly viscous liquid

    , Article Chemical Engineering Communications ; Volume 208, Issue 8 , 2021 , Pages 1143-1159 ; 00986445 (ISSN) Shahsavari, M ; Oshaghi, M. R ; Afshin, H ; Firoozabadi, B ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    Abstract
    In this study, the dynamics of the accelerated and steady-state motion of a single bubble in a quiescent highly viscous Newtonian liquid was investigated theoretically and experimentally. The presented mathematical model was based on Newton's second law of motion and a balance of buoyancy, drag, history, and added-mass forces. Due to the presence of non-linear terms in the equation of motion, homotopy perturbation method was used as a powerful analytical method to calculate the velocity analytically. To obtain accurate results in the experiments, a high-speed camera was used to record the bubble motion from the moment of detachment to the time at which the terminal velocity is reached.... 

    The role of flame–flow interactions on lean premixed lifted flame stabilization in a low swirl flow

    , Article Combustion Science and Technology ; 2021 ; 00102202 (ISSN) Shahsavari, M ; Farshchi, M ; Arabnejad, M. H ; Wang, B ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    Abstract
    Swirling flows have been widely used to stabilize lean premixed combustion in various gas turbines and furnaces. In such flows, understanding and characterizing the flame stabilization are of both practical and fundamental interests. It is known that the swirling motion decreases the flow velocity at the burner outlet, which contributes to flame stabilization. In low swirl flows, such a deceleration stabilizes a premixed flame aerodynamically. The present investigations, using large eddy simulations, study flame–flow interactions in lean premixed lifted flame stabilized in a low swirl flow. The results show that in addition to the swirling motion, combustion heat release reduces axial... 

    Modeling and Simulation of Bioelectrochemical Systems

    , M.Sc. Thesis Sharif University of Technology Karimi Alavijeh, Masih (Author) ; Yaghmaei, Soheyla (Supervisor)
    Abstract
    The objective of the present research, for the first time, was to configure a novel dynamic model to be applied in a general manner to simulate bioelectrochemical systems including microbial fuel cell and microbial electrolysis cell. Biochemical reactions engaged in organic substances degradation in both anolyte and biofilm were described by two anaerobic digestion models; Bernard’s anaerobic digestion model and ADM1. In addition, the bioelectrogenesis and electron transfer were modeled based on the direct electron transfer mechanism across the conductive biofilm. The biofilm simulation was established upon the one-dimensional distributions of substrates and microorganisms. In this study,... 

    Experimental Study of Low Swirl Burners Interferences

    , M.Sc. Thesis Sharif University of Technology Shahsavari, Mohammad (Author) ; Farshchi, Mohammad (Supervisor)
    Abstract
    One of the problems associated with lean premixed combustion is their stability. Low swirl flame is a modern technology for reducing NOx emissions and increasing stability.In this thesis, first, the effect of geometric parameters on the flame stability was investigated. This study was carried out in high fuel and oxidizer mixture flow rate. Having find, the most stable burner, two other burners with the same geometrical parameters were built. Stability of these three burners were analyzed. Second, they were located in a ring together in three different relative positions. In each configuration stability and NOx emissions of the burners were determined.The study shows that NOx and CO...