Search for: mazloum-ardakani--m
0.143 seconds

    Degradation of phenanthrene and anthracene by Nocardia otitidiscaviarum strain TSH1, a moderately thermophilic bacterium

    , Article Journal of Applied Microbiology ; Volume 105, Issue 2 , 11 July , 2008 , Pages 398-406 ; 13645072 (ISSN) Zeinali, M ; Vossoughi, M ; Ardestani, S. K ; Sharif University of Technology
    Aims: The metabolism of phenanthrene and anthracene by a moderate thermophilic Nocardia otitidiscaviarum strain TSH1 was examined. Methods and Results: When strain TSH1 was grown in the presence of anthracene, four metabolites were identified as 1,2-dihydroxy-1,2-dihydroanthracene, 3-(2-carboxyvinyl)naphthalene-2-carboxylic acid, 2,3-dihydroxynaphthalene and benzoic acid using gas chromatography-mass spectrometry (GC-MS), reverse phase-high performance liquid chromatography (RP-HPLC) and thin-layer chromatography (TLC). Degradation studies with phenanthrene revealed 2,2′-diphenic acid, phthalic acid, 4-hydroxyphenylacetic acid, o-hydroxyphenylacetic acid, benzoic acid, a phenanthrene... 

    Methane molecule over the defected and rippled graphene sheet

    , Article Solid State Communications ; Volume 152, Issue 15 , August , 2012 , Pages 1493-1496 ; 00381098 (ISSN) Shayeganfar, F ; Neek Amal, M ; Sharif University of Technology
    Elsevier  2012
    Adsorption of a methane molecule (CH 4) onto a defected and rippled graphene sheet is studied using ab initio and molecular mechanics calculations. The optimal adsorption position and orientation of this molecule on the graphene surface (motivated by the recent realization of graphene sensors to detect individual gas molecules) is determined and the adsorption energies are calculated. In light of the density of states, we used the SIESTA code. It is found that (i) classical force field yields adsorption energy comparable with experimental result and ab initio calculation; (ii) the periodic nature of the van der Waals potential energy stored between methane and perfect sheet is altered due to... 

    Efficient Friedel-crafts alkylation of indoles and pyrrole with enones and nitroalkene in water

    , Article Organic and Biomolecular Chemistry ; 2006, Volume 4, Issue 23, Pages 4275-4277 Azizi, N. (Najmodin) ; Arynasab, F ; Saidi, M. R ; Sharif University of Technology
    An operationally simple and entirely green protocol for heteropoly acid catalyst conjugate addition of indoles and pyrrole to unsaturated carbonyl compounds and nitro-alkene in water was investigated. It is important that the products arising from 1,2-addition were not observed under the reaction conditions. Pyrroles also readily underwent Michael addition at Α-positions under the same reaction conditions. Indole and many of its derivatives are present in many substances commonly found in nature. Micheal addition reactions are performed in organic solvents with the reactions in water are relatively scarce. The Michael addition between indole and methyl vinyl ketone in the presence of... 

    P-V-L Deep: A big data analytics solution for now-casting in monetary policy

    , Article Journal of Information Technology Management ; Volume 12, Issue 4 , 2021 , Pages 22-62 ; 20085893 (ISSN) Sarduie, M. H ; Kazemi, M. A ; Alborzi, M ; Azar, A ; Kermanshah, A ; Sharif University of Technology
    University of Tehran  2021
    The development of new technologies has confronted the entire domain of science and industry with issues of big data's scalability as well as its integration with the purpose of forecasting analytics in its life cycle. In predictive analytics, the forecast of near-future and recent past - or in other words, the now-casting - is the continuous study of real-time events and constantly updated where it considers eventuality. So, it is necessary to consider the highly data-driven technologies and to use new methods of analysis, like machine learning and visualization tools, with the ability of interaction and connection to different data resources with varieties of data regarding the type of big... 

    A new low voltage precision CMOS current reference with no external components

    , Article IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing ; Volume 50, Issue 12 , 2003 , Pages 928-932 ; 10577130 (ISSN) Dehghani, R ; Atarodi, S. M ; Sharif University of Technology
    A novel current reference with low temperature and supply sensitivity and without any external component has been developed in a 0.25 μm mixed-mode process. The circuit is based on a bandgap reference (BGR) voltage and a CMOS circuit similar to a beta multiplier. An NMOS transistor in triode region has been used in place of a resistor in conventional beta multiplier to achieve a current which has a negative temperature coefficient and only oxide thickness dependent. The BGR voltage has a positive temperature coefficient to cancel the negative temperature coefficient of the beta multiplier. The simulation results using Bsim3v3 model show max-to-min fluctuation of less than 1 % over a... 

    Modeling behavior in compositions of software architectural primitives

    , Article Proceedings - 19th International Conference on Automated Software Engineering, ASE 2004, Linz, 20 September 2004 through 24 September 2004 ; 2004 , Pages 371-374 ; 0769521312 (ISBN); 9780769521312 (ISBN) Mehta, N. R ; Medvidovic, N ; Sirjani, M ; Arbab, F ; Sharif University of Technology
    Software architectures and architectural styles are increasingly used for designing large-scale software systems. Alfa is a framework for the composition of style-based software architectures from a small set of primitives. It models the behavior of architectural components and connectors as orderings among events at their inputs and outputs. Formalizing such behavior is useful for checking conformance of architectures to their styles. We therefore propose a formal approach that uses data-abstract constraint automata to model the behavior of Alfa's compositions, and to verify their behavioral style conformance. We have also developed an automated conformance analyzer for Alfa. © 2004 IEEE  

    Kinetics and mechanism of diallyl sulfoxide pyrolysis; a combined theoretical and experimental study in the gas phase

    , Article RSC Advances ; Volume., 4, No (108) , Nov , 2014 , pp. (62809-62816) Izadyar, M. (Mohammad) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
    A combined experimental and computational study was carried out on the gas phase pyrolysis reaction of diallylsulfoxide. Allylalcohol and Thioacrolein were detected as the major products during a unimolecular reaction. Experimental kinetic studies were carried out via a static system over the pressure of 21-55 torr and temperature of 435.2-475.1 K. Based on the experiments, the reaction is homogeneous and proceeds through a zwitterionic intermediate. Computational studies at the DFT (B3LYP) and QCISD(T) levels with 6-311++G(d,p) basis set indicated a two-step concerted pathway as the possible route. Comparison between the experimental and theoretical activation parameters for the most... 

    Systems designed with an ionic liquid and molecular solvents to investigate the kinetics of an SNAr reaction

    , Article Progress in Reaction Kinetics and Mechanism ; Volume 38, Number 2 , 2013 , pp. 157-170 Salari, H. (Hadi) ; Padervand, M. (Mohsen) ; Gholami, M. R. (Mohammad Reza) ; Hallett, Jason P ; Sharif University of Technology
    The microscopic features of binary solvent systems formed by molecular solvents (methanol, ethanol, 2-methylpropan-2-ol, water, pyridine, acetonitrile, 1-propanol, 2-propanol, dimethylformamide) and the ionic liquid ([bmim]BF4) as cosolvent were used to select mixed solvents with particular characteristics. Molecular-microscopic solvent parameters corresponding to these binary mixtures were utilised to study the kinetics of the nucleophilic substitution reaction between 2-chloro-3,5-dinitropyridine and aniline to investigate and compare the effects of the solvents on a model chemical reaction. For these mixtures, the solvation behaviour is dominated by both the dipolarity/ polarisability and... 

    Some aspects of c = -2 theory

    , Article Fortschritte der Physik ; Volume 55, Issue 11-12 , 2007 , Pages 1289-1308 ; 00158208 (ISSN) Rajabpour, M. A ; Rouhani, S ; Saberi, A. A ; Sharif University of Technology
    We investigate some aspects of the c = -2 logarithmic conformal field theory (LCFT). At first, we calculate some correlators of logarithmic conformal fields which have third order singular OPE with the energymomentum tensor. Then, we argue about the fields in the c = -2 model which are associated with this kind of more general logarithmic primary fields. We go on to find fermionic representations for all the fields in the extended Kac table, in particular the untwisted sector. Moreover, we calculate the various OPEs of the fields, especially for the logarithmic energy-momentum tensor and by using these OPEs we find the exact finite transformation of this field. We briefly discuss about the... 

    A Multi-Objective Robust Optimization Model for Logistics Planning in the Earthquake Response Phase [electronic resource]

    , Article Transportation Research Part E: Logistics and Transportation Review, Elsevier ; Volume 49, Issue 1, January 2013, , Pages 217–249 Najafi, M. (Mehdi) ; Eshghi, Kourosh ; Dullaert, Wout ; Sharif University of Technology
    Usually, resources are short in supply when earthquakes occur. In such emergency situations, disaster relief organizations must use these scarce resources efficiently to achieve the best possible emergency relief. This paper therefore proposes a multi-objective, multi-mode, multi-commodity, and multi-period stochastic model to manage the logistics of both commodities and injured people in the earthquake response. Also, a robust approach is developed and used to make sure that the distribution plan performs well under the various situations that can follow an earthquake. Afterwards, it proposes a solution methodology according to hierarchical objective functions and uses it to illustrate the... 

    Preferential solvation and behavior of solvatochromic indicators in mixtures of an ionic liquid with some molecular solvents

    , Article The Journal of Physical Chemistry B ; vol.114 (29) , July , 2010 , pp 9586–9593 Salari, H. (Hadi) ; Khodadadi-Moghaddam, M.(Mohammad) ; Harifi-Mood, A. R. (Ali Reza) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
    Structural and intermolecular interactions of solvatochromic probes 4-nitroaniline, 4-nitroanisole, and Reichardt’s dye were investigated in the binary mixtures of 2-hydroxy ethylammonium formate as an ionic liquid with N,N-dimethyl formamide, dimethyl amine, and dimethyl sulfoxide. Solvatochromic parameters (ETN, normalized polarity parameter; π*, dipolarity/polarizability; β, hydrogen-bond acceptor basicity; α, hydrogen -bond donor acidity) were determined in ionic liquid mixtures at 25 °C using UV−vis spectroscopy. ETN parameters obtained from absorbance of Reichardt’s dye within various mixtures of ionic liquid were observed to be higher than predicted values from ideal additive... 

    Sole versus dual-sourcing under order dependent lead-times and prices [electronic resource]

    , Article Computers And Operations Research, Published in: Elsevier Journals ; Volume 36, Issue 12, December 2009, Pages 3272–3280 Sajjadieh, M. (Mohsen) ; Eshghi, Kourosh ; Sharif University of Technology
    In this paper, we consider a dual-sourcing model with constant demand and stochastic lead times. Two suppliers may be different in terms of purchasing prices and lead-time parameters. The ordering takes place when the inventory level depletes to a reorder level, and the order is split among two suppliers. Unlike previous works in the order splitting literature, the supply lead time between vendor and buyer as well as unit purchasing prices is considered to be order quantity dependent. The proposed model finds out the optimal reorder point, order quantity and splitting proportion, using a solution procedure. Numerical results show that neglecting the relationship between ordering batch size... 

    A system-level design method for RF receiver front-end with low power consumption

    , Article Analog Integrated Circuits and Signal Processing ; 2021 ; 09251030 (ISSN) Fazel, Z ; Atarodi, M ; Sadughi, S ; Sharif University of Technology
    Springer  2021
    Due to wireless communication’s rapid growth, the need for low power integrated transceivers is increasing. The receiver power is a major limiting factor, and the radio frequency (RF) front-end is often its significant power consuming part. Therefore, system-level design in which the overall specifications are distributed among RF front-end building blocks such that the minimum total power is consumed is crucial. A complete system-level design method for a low power RF front-end is presented in this paper. For this purpose, the performance of each block is modeled by its current and overdrive voltage. An analytical associated with a search-based optimization technique is employed to derive... 

    Deformation and stability of surface states in Dirac semimetals

    , Article Physical Review B ; Volume 97, Issue 16 , April , 2018 , Article number 165129 ; 24699950 (ISSN) Kargarian, M ; Lu, Y. M ; Randeria, M ; Sharif University of technology
    American Physical Society  2018
    The unusual surface states of topological semimetals have attracted a lot of attention. Recently, we showed [Proc. Natl. Acad. Sci. USA 113, 8648 (2016)PNASA60027-842410.1073/pnas.1524787113] that for a Dirac semimetal (DSM) arising from band inversion, such as Na3Bi and Cd3As2, the expected double Fermi arcs on the surface are not topologically protected. Quite generally, the arcs deform into states similar to those on the surface of a strong topological insulator. Here we address two questions related to deformation and stability of surface states in DSMs. First, we discuss why certain perturbations, no matter how large, are unable to destroy the double Fermi arcs. We show that this is... 

    Data envelopment analysis based comparison of two hybrid multi-criteria decision-making approaches for mobile phone selection: a case study in Iranian telecommunication environment

    , Article International Journal of Information and Decision Sciences ; Volume 1, Issue 2 , 2008 , Pages 194-220 ; 17567017 (ISSN) Mahdavi, I ; Fazlollahtabar, H ; Mozaffari, E ; Heidari, M ; Mahdavi Amiri, N ; Sharif University of Technology
    The arrival of the mobile phone and its rapid and widespread growth may well be seen as one of the most significant developments in the fields of communication and information technology over the past two decades. The aim of this study is to compare two hybrid multi-criteria decision-making (MCDM) approaches to evaluate the mobile phone options with respect to user’s preferences. Firstly, we identify the most desirable features influencing the choice of a mobile phone. This is realised through a survey conducted among the target group, the experiences of the telecommunication sector experts and the studies in the literature. Secondly, two MCDM methods are used in the evaluation procedure.... 

    An experimental and theoretical study on the structure and photoactivity of XFe2O4 (X = Mn, Fe, Ni, Co, and Zn) structures1

    , Article Russian Journal of Physical Chemistry A ; Volume, 88, Issue 13 , December , 2014 , pp. 2451-2461 ; 1531-863X Padervand, M ; Vossoughi, M ; Yousefi, H ; Salari, H ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
    XFe2O4 magnetic nanoparticles (X = Mn, Fe, Co, Ni, and Zn) were prepared by using two methods: coprecipitation and hydrothermal. The synthesized nanoparticles were compared according to the separation in an external magnetic field and finally, the hydrothermal method was specified as a better synthesis method. The magnetic nanoparticles were characterized by physico-chemical analysis methods such as Vibrating Sample Magnetometer (VSM), X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), nitrogen adsorption-adsorption isotherm and Transmission Electron Microscopy (TEM). Magnetic properties of synthesized nanoparticles were studied by ab-initio theoretical methods to... 

    Employing humanoid robots for teaching english language in Iranian junior high-schools [electronic resource]

    , Article International Journal of Humanoid Robotics ; Vol. 11, No. 3 (2014) 1450022 Alemi, M. (Minoo) ; Meghdari, Ali ; Ghazisaedy, Maryam ; Sharif University of Technology
    This paper presents the effect of robotics assisted language learning (RALL) on the vocabulary learning and retention of Iranian English as foreign language (EFL) junior high school students in Tehran, Iran. After taking a vocabulary pre-test, 46 beginner level female students at the age of 12, studying in their first year of junior-high participated in two groups of RALL (30 students) and non-RALL (16 students) in this study. The textbook used was the English book (Prospect-1) devised by the Iranian Ministry of Education for 7th graders, and the vocabulary taught and tested (pre-test and post-test) were taken from this book. Moreover, the treatment given by a teacher accompanied by a... 

    Reliability of recurrence quantification analysis measures of the center of pressure during standing in individuals with musculoskeletal disorders

    , Article Medical Engineering and Physics ; Volume 32, Issue 7 , 2010 , Pages 808-812 ; 13504533 (ISSN) Mazaheri, M ; Negahban, H ; Salavati, M ; Sanjari, M. A ; Parnianpour, M ; Sharif University of Technology
    Although the application of nonlinear tools including recurrence quantification analysis (RQA) has increasingly grown in the recent years especially in balance-disordered populations, there have been few studies which determine their measurement properties. Therefore, a methodological study was performed to estimate the intersession and intrasession reliability of some dynamic features provided by RQA for nonlinear analysis of center of pressure (COP) signals recorded during quiet standing in a sample of patients with musculoskeletal disorders (MSDs) including low back pain (LBP), anterior cruciate ligament (ACL) injury and functional ankle instability (FAI). The subjects completed postural... 

    Comparison and reduction of the chemical kinetic mechanisms proposed for thermal partial oxidation of methane (TPOX) in porous media

    , Article International Journal of Hydrogen Energy ; Volume 46, Issue 37 , 2021 , Pages 19312-19322 ; 03603199 (ISSN) Fotovat, F ; Rahimpour, M ; Sharif University of Technology
    Elsevier Ltd  2021
    The effectiveness and reducibility of the methane combustion kinetic mechanisms were examined for the TPOX process in a porous medium. To this end, TPOX was successfully simulated using ANSYS CHEMKIN-Pro through a reactor network model composed of perfectly stirred and honeycomb-monolith reactors. The efficacy of six chemical kinetic mechanisms was compared for the equivalence ratios (ERs) ranging from 2.4 to 2.6 with a constant thermal load of 1540 kW/m2. This comparison revealed that Konnov was the most successful mechanism in the prediction of the H2 and CO mole fractions. This mechanism along with the GRI-3.0 and USC-Mech 2.0 mechanisms were then reduced by the direct relation graph with... 

    On the reduction of the number of required motions in the dynamic analysis using a refined spectral matching

    , Article Earthquake and Structures ; Volume 21, Issue 4 , 2021 , Pages 425-444 ; 20927614 (ISSN) Harati, M ; Mashayekhi, M ; Mohammadnezhad, H ; Jaberi, H ; Estekanchi, H. E ; Sharif University of Technology
    Techno-Press  2021
    This study aims to show the efficiency of a proposed spectral matching technique for the reduction of required ground motions in the dynamic time history analysis. In this non-stationary spectral matching approach, unconstrained optimization is employed to adjust the signal to match a target spectrum. Adjustment factors of discrete wavelet transform (DWT) coefficients associated with the signals are then considered as decision variables and the Levenberg-Marquardt algorithm is employed to find the optimum values of DWT coefficients. This matching algorithm turns out to be quite effective in the spectral matching objective, where matching at multiple damping ratios can be readily achieved....