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Implementing an automated feedback program for a foreign language writing course: A learner-centric study
, Article Journal of Computer Assisted Learning ; Volume 37, Issue 5 , 2021 , Pages 1494-1507 ; 02664909 (ISSN) ; Fotoohnejad, S ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
Considering the prominence attached to written corrective feedback (WCF) within the domain of second/foreign language (L2) acquisition, automated writing evaluation (AWE) tools have steadily gained ground over the last two decades. The current study was an attempt to investigate the extent incorporating an AWE program, known as Criterion®, within a process writing framework would affect learners' writing quality in an English as a foreign language context. Moreover, we drew a comparison between the overall effects of computer- versus teacher-generated WCF. Participants consisted of 53 tertiary level students from two intact essay-writing classes. The within-group findings revealed that the...
Characterization of constrained aged niti strips for using in artificial muscle actuators
, Article International Journal of Engineering, Transactions A: Basics ; Volume 24, Issue 4 , 2011 , Pages 321-329 ; 17281431 (ISSN) ; Sadrnezhaad, S. K ; Sharif University of Technology
2011
Abstract
Marvelous bending/straightening effects of two-way shape memory alloy (TWSMA) help their employment in design and manufacturing of new medical appliances. Constrained ageing with bending load scheme can induce two-way shape memory effect (TWSME). Scanning electron microscopic (SEM) analysis, electrical resistivity measurement (ERM) and differential scanning calorimetry (DSC) are employed to determine the property change due to flat strip constrained aging. Results show that flat-annealing prior to the aging shifts NiTi transformations temperatures to higher values. Superelastic behavior of the as-received/flat- annealed/aged samples with more adequate transition temperatures due to...
The impact of computer-aided concept mapping on EFL learners' lexical diversity: A process writing experiment
, Article ReCALL ; Volume 33, Issue 3 , 2021 , Pages 214-228 ; 09583440 (ISSN) ; Saffari, E ; Rezaei, S ; Sharif University of Technology
Cambridge University Press
2021
Abstract
Nowadays, many second/foreign language (L2) academic writing instruction programs place a high premium on pre-writing strategies. The current study examined the effect of software-supported concept mapping on lexical diversity (LD) of English learners' argumentative essays within a process writing framework. Additionally, the relationship between the learners' LD and their overall writing quality was investigated. To this end, 53 university English as a foreign language (EFL) undergraduates were assigned to a computer-aided concept mapping (CACM) and a traditional outlining condition over a span of seven weeks. The CACM group was instructed through the graphic organizer software...
A multi-dimensional fairness combinatorial double-sided auction model in cloud environment
, Article 2016 8th International Symposium on Telecommunications, IST 2016, 27 September 2016 through 29 September 2016 ; 2017 , Pages 672-677 ; 9781509034345 (ISBN) ; Movaghar, A ; Hassanzadeh, H. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
In cloud investment markets, consumers are looking for the lowest cost and a desirable fairness while providers are looking for strategies to achieve the highest possible profit and return. Most existing models for auction-based resource allocation in cloud environments only consider the overall profit increase and ignore the profit of each participant individually or the difference between the rich and the poor participants. This paper proposes a multi-dimensional fairness combinatorial double auction (MDFCDA) model which strikes a balance between the revenue and the fairness among participants. We solve a winner determination problem (WDP) through integer programming which incorporates the...
In-situ hydrothermal synthesis of Na3MnCO3PO4/rGO hybrid as a cathode for Na-ion battery
, Article Electrochimica Acta ; Volume 208 , 2016 , Pages 188-194 ; 00134686 (ISSN) ; Sadrnezhaad, S. K ; Chen, G ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Novel Na3MnCO3PO4 (NMCP)/reduced graphene oxide (rGO) nanocomposite was successfully synthesized via one-step hydrothermal method. The produced materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetry (TG), galvanostatic charge/discharge test and inductively coupled plasma optical emission spectroscopy (ICP-OES). Obtained results indicate the formation of ∼25 nm NMCP nanoparticles randomly distributed on rGO sheets. As a promising cathode material for Na-ion batteries, the hybrids deliver gravimetric discharge capacities of...
Ball mill assisted synthesis of Na3MnCO3PO4 nanoparticles anchored on reduced graphene oxide for sodium ion battery cathodes
, Article Electrochimica Acta ; Volume 220 , 2016 , Pages 683-689 ; 00134686 (ISSN) ; Sadrnezhaad, S. K ; Chen, G ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Na3MnCO3PO4 (NMCP) particles were synthesized via ball milling of Mn(NO3)2.4H2O, Na2HPO4.2H2O and Na2CO3.H2O powders. The particles were anchored onto reduced graphene oxide (rGO) sheets during hydrothermal reduction process under stirring. Materials produced were characterized by x-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric (TG) measurement and galvanostatic charge/discharge tests. Results showed that dissolution of ball milling products in DI water is an effective method for separation of NMCP from byproducts. Best milling time for production of pure NMCP of minimum particle...
Concurrent project scheduling and material planning: a genetic algorithm approach
, Article Scientia Iranica ; Volume 16, Issue 2 E , 2009 , Pages 91-99 ; 10263098 (ISSN) ; Shadrokh, S ; Hassanzadeh, F ; Sharif University of Technology
2009
Abstract
Scheduling projects incorporated with materials ordering results in a more realistic problem. This paper deals with the combined problem of project scheduling and material ordering. The purpose of this paper is to minimize the total cost of this problem by determining the optimal values of activity duration, activity finish time and the material ordering schedule subject to constraints. We employ a genetic algorithm approach to solve it. Elements of the algorithm, such as chromosome structure, unfitness function, crossover, mutation and local search operations are explained. The results of the experimentation are quite satisfactory
An investigation of crystallization kinetics of the Na3MnCO3PO4 cathode material, synthesized by the hydrothermal method
, Article Materials Chemistry and Physics ; Volume 214 , 2018 , Pages 73-79 ; 02540584 (ISSN) ; Sadrnezhaad, S. K ; Ghorbanzadeh, M ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Na3MnCO3PO4 (NMCP) is produced by hydrothermal synthesis for rechargeable sodium-ion battery (SIB) cathode. Mechanism of formation of NMCP was investigated by measuring the influence of time and temperature on the rate of production of the NMCP crystallites. X-ray diffraction analysis of the synthesized samples showed that MnCO3 first formed as an intermediate phase. Na3MnCO3PO4 was, however, the last phase retained after 24 h of the hydrothermal process at 120 °C. Sigmoidal shape of the crystallization curves followed the Avrami–Erofeev model which described the chemical kinetics of the Na3MnCO3PO4 formation. Respective apparent activation energies of 29.10 for nucleation and 73.91 kJ/mol...
Halide (Cl-, Br-, I-) influence on the electronic properties of macrocyclic nickel(II) complexes: Ab-initio DFT study
, Article Journal of the Korean Chemical Society ; Volume 57, Issue 3 , 2013 , Pages 311-315 ; 10172548 (ISSN) ; Akhtari, K ; Hassanzadeh, K ; Piltan, M ; Saaidpour, S ; Abedi, M ; Sharif University of Technology
2013
Abstract
The geometry structures of hexa-coordinated [NiLX]X complexes (X = Cl -, Br-, I-) {L = 8,9,18,19-tetrahydro-7H,17H- dibenzo[f,o] [1,5,9,13]dioxadiaza cyclohexadecine-8,18-diol} are optimized by density functional theory (DFT) using B3LYP/LANL2DZ. The calculated geometric parameters are in good agreement with the corresponding experimental values. Calculation results about these complexes show that dipole moment decreases, and the energy levels of HOMOs descend from iodo-complex to chloro-complex. The energy levels of HOMOs descend gently from iodo-complex to chloro-complex, while the energy levels of LUMOs in the present complexes are almost similar; therefore the energy gapes between HOMOs...
Climate change or irrigated agriculture – what drives the water level decline of Lake Urmia
, Article Scientific Reports ; Volume 10, Issue 1 , 2020 ; Darehshouri, S ; Hassanzadeh, E ; Tajrishy, M ; Schüth, C ; Sharif University of Technology
Nature Research
2020
Abstract
Lake Urmia is one of the largest hypersaline lakes on earth with a unique biodiversity. Over the past two decades the lake water level declined dramatically, threatening the functionality of the lake’s ecosystems. There is a controversial debate about the reasons for this decline, with either mismanagement of the water resources, or climatic changes assumed to be the main cause. In this study we quantified the water budget components of Lake Urmia and analyzed their temporal evolution and interplay over the last five decades. With this we can show that variations of Lake Urmia’s water level during the analyzed period were mainly triggered by climatic changes. However, under the current...
Preparation and characterization of self-electrical stimuli conductive gellan based nano scaffold for nerve regeneration containing chopped short spun nanofibers of PVDF/MCM41 and polyaniline/graphene nanoparticles: Physical, mechanical and morphological studies
, Article International Journal of Biological Macromolecules ; 2020 ; Ramazani S., A ; H Shirazi, F ; Hassanzadeh Nemati, N ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Conductive self -electrical stimuli bioactive scaffolds could be used the potential for peripheral nerve regeneration with the maximum efficiency. To produce such conductive self-electrical stimuli bioactive scaffolds, chopped spun piezoelectric nanofibers of polyvinylidene fluoride/mesoporous silica nanoparticle (PVDF/MCM41) are prepared and incorporated in gellan/polyaniline/graphene (gellan/PAG) nanocomposites which have been previously prepared by incorporation of polyaniline/graphene (PAG) nanoparticles in gellan gel at 80 °C. Highly conductive binary doped polyaniline/graphene nanoparticles are prepared by chemical oxidative polymerization of aniline monomer using in-suite...
Magnetic stirring assisted hydrothermal synthesis of Na3MnCO3PO4 cathode material for sodium-ion battery
, Article Ceramics International ; Volume 47, Issue 19 , 2021 , Pages 26929-26934 ; 02728842 (ISSN) ; Sadrnezhaad, S.K ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Na3MnCO3PO4 (NMCP) is considered one of the promising cathode materials for sodium-ion batteries due to its high theoretical capacity. The hydrothermal method is an efficient, environmental-friendly, and simple route with low instrument cost to prepare active cathode materials such as NMCP. In this research, magnetic stirring was applied to promote the hydrothermal synthesis, and NMCP was produced by controlling different stirring times. This method results in the formation of pure NMCP upon only 45 min processing time. According to the ICP results, the Na to Mn ratio in the NMCP approached the stoichiometric value of 3 by prolonging the stirring time. By analyzing the charge-discharge...
A mixed methods approach to exploring grammar learning strategies in self-regulation task phases: Evidence from grounded theory and regression analysis
, Article Language Teaching Research ; 2022 ; 13621688 (ISSN) ; Ranjbar, M ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
While research into various dimensions of language learning strategies has been thriving over the recent years, grammar learning strategies (GLS) have largely remained under-explored. The present mixed methods research aimed to explore GLS in the three stages of classroom grammar tasks, while striving to determine the sequence of GLS and their contribution to grammar proficiency. In the qualitative phase, 13 participants partook in stimulated recall and semi-structured interviews after completing consciousness-raising (CR) tasks. Then, the grounded theory (GT) methodology was applied to conceptualize a theoretical model. For the quantitative phase, a modified version of Pawlak’s Grammar...
Single and double stage sintering of mechanically alloyed powder for nanostructured Ti6Al4V foams usable in cancellous scaffolds
, Article International Heat Treatment and Surface Engineering ; Volume 7, Issue 1 , 2013 , Pages 43-48 ; 17495148 (ISSN) ; Aryana, M ; Hassanzadeh Nemati, N ; Alizadeh, M ; Ebadifar, A ; Sharif University of Technology
2013
Abstract
Mechanical alloying and sintering were used to fabricate nanostructured Ti6Al4V scaffolds of highly controllable pore geometry and fully interconnected porous network. Elemental powders were milled for different periods of time (10, 20, 30, 40 and 60 h), mixed with 40-60 vol.-% of 200-400 μm cuboidal NaCl, compacted at 500-600 MPa and sintered according to single or double stage heat treatment regimes at 790 and 950°C under vacuum. After sintering, the samples were soaked in distilled water to washout the NaCl. Foamy microstructures were obtained showing well shaped biopores and fragmentary embedded micropores. The shape of initial NaCl was copied into the biopores which had highly...
Gellan gel comprising short PVDF based-nanofibers: The effect of piezoelectric nanofiber on the mechanical and electrical behavior
, Article Materials Today Communications ; Volume 26 , 2021 ; 23524928 (ISSN) ; Ramazani S. A., A ; H-Shirazi, F ; Hassanzadeh Nemati, N ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Gel-fiber structure with the potential of extracellular matrix (ECM) mimics can be introduced as a suitable candidate for bioengineering applications. In this study, piezoelectric gellan gel-fiber was prepared with incorporating poly(vinylidenefluoride) (PVDF)/glass-flake in the gellan matrix. Glass-flake nanoparticles were modified with silane group, PVDF/glass-flake nanofibers were synthesized and short-strand nanofibers were fabricated using the mechanical homogenizer method. Brunauer–Emmett–Teller (BET), Fourier-transform infrared spectroscopy (FTIR), and Thermogravimetric analysis (TGA) analyses were used for surface modification study, and scanning electron microscopy (SEM),...
Coupling of ANISN & MCNP Computer Codes for Neutron Importance Calculation
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor)
Abstract
For many reasons the Montecarlo method is chosen for investigation of problems like shielding. Nowadays, superiority of utilizing the codes based upon Montecarlo methods such as using cross sections with continuous energy or using exact models of complex geometries, is obvious for everyone. But obtaining results with least possible variance is extremely important. variance reduction methods usedfor achieving exact results with less calculating time. Up to now in the MCNP codes, many methods have been utilized for reducing the variance. One of the methods which have recently attracted attentions is using the importance function. For obtaining importance function we need to solve the...
Improving the Stability of an Urban Traffic Network with Limited Data by Using Percolation Theory and Dynamic Clustering
, M.Sc. Thesis Sharif University of Technology ; Amini, Zahra (Supervisor)
Abstract
One of the most vital aspects of understanding the traffic phenomenon is scrutinizing the traffic transition status, such as the transition from free flow to congestion. The Percolation Theory is a renowned theory focusing on analyzing various network types to detect the critical zones, which are the zones including links that are important to control to improve stability. By calculating the quality indices of network links, the Percolation Theory can simulate the traffic percolation propagation in the network and determine possible critical zones for further analysis. Most studies in this field assume access to data of several traffic parameters for the entire transportation network, such...
A density functional theory study of the reactivity descriptors and antioxidant behavior of Crocin
, Article Computational and Theoretical Chemistry ; Volume 1013 , June , 2013 , Pages 123-129 ; 2210271X (ISSN) ; Hassanzadeh, K ; Fakhraei, B ; Fakhraei, N ; Hassanzadeh, H ; Zarei, S. A ; Sharif University of Technology
2013
Abstract
The molecular characteristics of Crocin (digentiobiosyl-8,8'-diapocarotene-8,8'-oate; C44H64O24), naturally occurring carotenoid pigment compound, such as: the ionization potential (I), electron affinity (A), electronegativity (χ), electrophicility (ω), and hardness have been calculated using Density Functional Theory (DFT) approach with B3LYP/6-31G(d,p) level of theory. The plots of Frontier Molecular Orbital and molecular electrostatic potential (MEP) for Crocin molecule along with the spin density distribution for its cation radical have been demonstrated. For the first time, we indicated the chemically active sites of the Crocin molecule by Fukui functions. Calculated components of...
A 32kb 90nm 10T-cell sub-threshold SRAM with improved read and write SNM
, Article 2013 21st Iranian Conference on Electrical Engineering ; May , 2013 ; 9781467356343 (ISBN) ; Zamani, M ; Hajsadeghi, K ; Sharif University of Technology
2013
Abstract
The constraints of power saving have compelled SRAM designers to consider sub-threshold area as a viable choice. The biggest barrier of this progress is the stability of SRAM's cells and the correct operations. In this paper a 10T cell structure has been proposed with 90% read and 50% write SNM improvement in comparison to the conventional 6T cell. The hold SNM value is about the 6T cell SRAM. Also using differential read method in the proposed structure causes high read performance and using simpler sense amplifier. The symmetric configuration of this structure helps the SRAM has simpler layout and lower transistor mismatch. Using 90nm TSMC CMOS, 32kb 10T cell SRAM in sub-threshold area is...
A practical R&D selection model using fuzzy pay-off method
, Article International Journal of Advanced Manufacturing Technology ; Volume 58, Issue 1-4 , June , 2012 , Pages 227-236 ; 02683768 (ISSN) ; Collan, M ; Modarres, M ; Sharif University of Technology
2012
Abstract
The aim of this paper is to develop a practical R&D portfolio selection model that addresses effective R&D project valuation issue, while it tackles R&D uncertainty in portfolio optimization. Fuzzy sets theory is employed to capture and model the inaccuracy in project information. To avoid the well-known complications of fuzzy real option valuation, the fuzzy pay-off method is used to more effectively value R&D projects. The resulting problem is formulated as a fuzzy zero-one integer programming model which is later transformed into a crisp mathematical formulation to solve the problem for various degrees of risk. A numerical example is used to illustrate the proposed approach