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    Synthesis and swelling behavior of a new superabsorbent hydrogel network based on polyacrylamide grafted onto salep [electronic resource]

    , Article Journal of Applied Polymer Science ; Volume 112, Issue 5, pages 2625–2633, 5 June 2009 Pourdjavadi, A. (Ali) ; Rezanejad Barajee, Ghasem ; Soleyman, Rouhollah ; Sharif University of Technology
    Abstract
    Synthesis and swelling behavior of a new superabsorbent hydrogel based on natural salep grafted with polyacrylamide is described. The new superabsorbent hydrogel biopolymer was synthesized via radical crosslinking and graft copolymerization of acrylamide monomer onto salep backbones. Regarding to the water absorption of hydrogel, the best synthesis condition is reported. FTIR spectroscopy and thermogravimetric analysis were used to confirm the structure of the final product and a mechanism for superabsorbent hydrogel formation was also suggested. After preparing the desired hydrogels based on optimum condition, several factors affecting the swelling behavior of hydrogel including pH of... 

    A novel composite gold/gold nanoparticles/carbon nanotube electrode for frequency-stable micro-electrical impedance tomography

    , Article Journal of Materials Science: Materials in Electronics ; Volume 31, Issue 13 , 2020 , Pages 10803-10810 Rezanejad Gatabi, Z ; Mohammadpour, R ; Rezanejad Gatabi, J ; Mirhoseini, M ; Sasanpour, P ; Sharif University of Technology
    Springer  2020
    Abstract
    A novel electrode structure is introduced for micro-electrical impedance tomography. The composite electrode structure is made up of gold nanoparticles (AuNPs) and carbon nanotube (CNT) which are deposited on the surface. The nanostructure-based composition of electrodes improved the effective surface area, increased the double-layer capacitance of electrodes, and enhanced the electron transfer on the electrode–analyte interface. The proposed electrodes exhibit lower frequency-dependent electrical properties in impedance measurement. © 2020, Springer Science+Business Media, LLC, part of Springer Nature  

    Academic dishonesty at universities: The case of plagiarism among iranian language students

    , Article Journal of Academic Ethics ; Volume 11, Issue 4 , 2013 , Pages 275-295 ; 15701727 (ISSN) Rezanejad, A ; Rezaei, S ; Sharif University of Technology
    2013
    Abstract
    This study investigated Iranian language students' perception of and familiarity with plagiarism, their attitudes toward their professors regarding this issue, and their reasons for doing so. The participants were 122 undergraduate and graduate language students in Translation, Literature, TEFL, and Linguistics who filled out a validated and piloted questionnaire. Overall, the results indicated that students had different views about the definition of plagiarism and plagiarism was mostly perceived by students as using someone else's words as if they were their own rather than taking someone's ideas without permission. It was also found that in their academic career, students mostly consider... 

    Down from the pedestal: Revisiting the exploit of literature in EFL language classes

    , Article International Journal of Applied Linguistics and English Literature ; Volume 4, Issue 2 , 2015 , Pages 158-168 ; 22003592 (ISSN) Rezanejad, A ; Lari, Z ; Mosalli, Z ; Sharif University of Technology
    Australian International Academic Centre PTY LTD  2015
    Abstract
    According to Arthur (2006, p. 200), “Through the use of literature, a language learning experience might become at the same time a source of immediate pleasure and satisfaction for the student. This possibility makes literature an appealing teaching device for ESL teachers”. However, numerous factors may contribute to the teachers’ lack of interest in using literary texts as a teaching tool. This study was an attempt to investigate Iranian EFL teachers’ attitude toward using literature in language classes and their perception toward the probable reasons of some teachers’ lack of interest in doing so. Altogether forty-four language teachers (19 females and 25 males, with a mean age of 26)... 

    Novel high capacity swelling superabsorbent composite and its potential for controlled release of fertilizers

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 29, Issue 4 , 2010 , Pages 113-123 ; 10219986 (ISSN) Pourjavadi, A ; Soleyman, R ; Rezanejad Bardajee, G ; Sharif University of Technology
    2010
    Abstract
    A hydrophilic macromolecular network is prepared by performing graft opolymerization of poly (sodium acrylate) chains onto salep and silica gel. The reaction parameters affecting the water absorbency of the superabsorbent composite were optimized using Taguchi method. FT-IR spectroscopy and Thermo Gravimetric Analysis (TGA) were used for confirming the structure of the final product and morphology of the synthesized superabsorbent composite was examined by SEM. The swelling behavior of optimum superabsorbent composite was measured in various swelling media. In addition, swelling kinetics and on-off switching behavior were investigated. In order to evaluate the controlled release potential of... 

    Rating EFL Learner's Interlanguag Pragmatic Competence by Native and Non-native English Speaking Teachers

    , M.Sc. Thesis Sharif University of Technology Rezanejad, Atefeh (Author) ; Alemi, Minoo (Supervisor) ; Eslami Rasekh, Zohreh (Co-Advisor)
    Abstract
    Pragmatic assessment and consistency in rating are among the subject matters which are still in need of more in-depth investigations. The significance of the issue is highlighted when remembering that inconsistency in ratings would surely damage the test fairness issue in assessment and lead to much diversity in ratings. The purpose of this study was investigating the criteria that native (American) and non-native (Iranian) English speaking teachers considered while rating the pragmatic productions of Iranian EFL learners regarding the two speech acts of compliment and compliment response. Overall, a hundred and twenty teachers (sixty native and sixty non-native raters) participated in this... 

    Analyzing Existing Challenges of Building Construction Supervision Contracts and Proposing A Balanced Form of Supervision Contract

    , M.Sc. Thesis Sharif University of Technology Rezanejad, Mohsen (Author) ; Alvanchi, Amin (Supervisor) ; Jafari Fasharaki, Mohammad (Supervisor)
    Abstract
    Supervision is considered one of the fundamental pillars in the construction of building projects within the country's engineering system. Enhancing the supervision process for construction projects can significantly improve the quality of buildings nationwide. However, in many cases, the supervision process has not effectively fulfilled its assigned responsibilities and has encountered numerous challenges. This study aims to identify and prioritize the challenges present in the operational processes of supervisors within the engineering system. The primary objective of this research is to identify and analyze these challenges and propose solutions to enhance supervisors' performance and... 

    Sandblasting improves the performance of electrodes of miniature electrical impedance tomography via double layer capacitance

    , Article Heliyon ; Volume 6, Issue 4 , 2020 Rezanejad Gatabi, Z ; Mohammadpour, R ; Gatabi, J. R ; Mirhoseini, M ; Ahmadi, M ; Sasanpour, P ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Effect of sandblasting of the copper electrode structures before deposition of gold thin film for micro electrical impedance tomography (EIT) system has been studied experimentally. The comparison has been performed on the unmodified copper electrodes and the sandblasted electrodes before deposition of gold layer, using structural analysis while their performance in EIT system has been measured and analyzed. The results of scanning electron microscopy and atomic force microscopy show that the sandblasting of the electrodes results in the deposition of gold film with smaller grain size and uniformly, comparing to the unmodified structure. The measurement of impedance shows that the... 

    Intelligent semi-active vibration control of eleven degrees of freedom suspension system using magnetorheological dampers

    , Article Journal of Mechanical Science and Technology ; Volume 26, Issue 2 , 2012 , Pages 323-334 ; 1738494X (ISSN) Zareh, S. H ; Sarrafan, A ; Khayyat, A. A. A ; Zabihollah, A ; Sharif University of Technology
    2012
    Abstract
    A novel intelligent semi-active control system for an eleven degrees of freedom passenger car's suspension system using magnetorheological (MR) damper with neuro-fuzzy (NF) control strategy to enhance desired suspension performance is proposed. In comparison with earlier studies, an improvement in problem modeling is made. The proposed method consists of two parts: a fuzzy control strategy to establish an efficient controller to improve ride comfort and road handling (RCH) and an inverse mapping model to estimate the force needed for a semi-active damper. The fuzzy logic rules are extracted based on Sugeno inference engine. The inverse mapping model is based on an artificial neural network... 

    Performance and exhaust emission characteristics of a spark ignition engine operated with gasoline and CNG blend

    , Article Proceedings of the Spring Technical Conference of the ASME Internal Combustion Engine Division ; 2012 , Pages 179-187 ; 15296598 (ISSN) ; 9780791844663 (ISBN) Dashti, M ; Hamidi, A. A ; Mozafari, A. A ; Sharif University of Technology
    2012
    Abstract
    Using CNG as an additive for gasoline is a proper choice due to higher octane number of CNG enriched gasoline with respect to that of gasoline. As a result, it is possible to use gasoline with lower octane number in the engine. This would also mean the increase of compression ratio in SI engines resulting in higher performance and lower gasoline consumption. Over the years, the use of simulation codes to model the thermodynamic cycle of an internal combustion engine have developed tools for more efficient engine designs and fuel combustion. In this study, a thermodynamic cycle simulation of a conventional four-stroke spark-ignition engine has been developed. The model is used to study the... 

    A comparative study of the performance of a SI engine fuelled by natural gas as alternative fuel by thermodynamic simulation

    , Article 2009 ASME Internal Combustion Engine Division Fall Technical Conference, ICEF 2009, Lucerne, 27 September 2009 through 30 September 2009 ; 2009 , Pages 49-57 ; 9780791843635 (ISBN) Dashti, M ; Hamidi, A. A ; Mozafari, A. A ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2009
    Abstract
    With the declining energy resources and increase of pollutant emissions, a great deal of efforts has been focused on the development of alternatives for fossil fuels. One of the promising alternative fuels to gasoline in the internal combustion engine is natural gas [1-5]. The application of natural gas in current internal combustion engines is realistic due to its many benefits. The higher thermal efficiency due to the higher octane value and lower exhaust emissions including CO2 as a result of the lower carbon to hydrogen ratio of the fuel are the two important feature of using CNG as an alternative fuel. It is well known that computer simulation codes are valuable economically as a cost... 

    Analytical and experimental analyses of nonlinear vibrations in a rotary inverted pendulum

    , Article Nonlinear Dynamics ; Volume 107, Issue 3 , 2022 , Pages 1887-1902 ; 0924090X (ISSN) Dolatabad, M.R ; Pasharavesh, A ; Khayyat, A. A. A ; Sharif University of Technology
    Springer Science and Business Media B.V  2022
    Abstract
    Gaining insight into possible vibratory responses of dynamical systems around their stable equilibria is an essential step, which must be taken before their design and application. The results of such a study can significantly help prevent instability in closed-loop stabilized systems by avoiding the excitation of the system in the neighborhood of its resonance. This paper investigates nonlinear oscillations of a rotary inverted pendulum (RIP) with a full-state feedback controller. Lagrange’s equations are employed to derive an accurate 2-DoF mathematical model, whose parameter values are extracted by both the measurement and 3D modeling of the real system components. Although the governing... 

    A suction-controlled ring device to measure the coefficient of lateral soil pressure in unsaturated soils

    , Article Geotechnical Testing Journal ; Volume 44, Issue 1 , 2020 Pirjalili, A ; Garakani, A. A ; Golshani, A ; Mirzaii, A ; Sharif University of Technology
    ASTM International  2020
    Abstract
    A suction-controlled ring device has been developed to continuously measure the coefficient of lateral soil pressure in deformable unsaturated soil samples from the at-rest to the active condition under application of increasing vertical pressure and controlled matric suction. The device incorporates a thin aluminum specimen ring equipped with horizontal strain gages for recording the lateral soil strains. In addition, a sensor recording water volume changes is utilized to continuously monitor the degree of saturation of the soil sample during tests. The matric suction within the soil texture is controlled using the axis translation technique. In order to verify the performance of the ring... 

    Gum tragacanth gels as a new supporting matrix for immobilization of whole-cell

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 24, Issue 4 , 2005 , Pages 1-7 ; 10219986 (ISSN) Otady, M ; Vaziri, A ; Seifkordi, A. A ; Kheirolomoom, A ; Sharif University of Technology
    2005
    Abstract
    We introduce a new smooth, non-toxic, biocompatible method for cross-linking of gum tragacanth (GT), a polysaccharide of natural origin, in order to serve as a new supporting matrix for immobilization systems. The modified gum is used as a matrix for the catalysis of the conversion of benzyl penicillin to 6-aminopenicillanic acid (6-APA) by means of Escherichia coli ATCC11105 with penicillin G acylase (PGA) activity. The results show that GT beads can not only serve as a proper matrix for immobilization, but show enhanced hydrolysis rate and stability compared to other immobilization systems used for this reaction. This signifies the potential of GT as a biocompatible matrix for... 

    True Class-E Design For Inductive Coupling Wireless Power Transfer Applications

    , Article 30th International Conference on Electrical Engineering, ICEE 2022, 17 May 2022 through 19 May 2022 ; 2022 , Pages 864-868 ; 9781665480871 (ISBN) Haeri, A. A. R ; Safarian, A ; Fotowat Ahmady, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2022
    Abstract
    The Class-E power amplifier has been widely studied and formulated in the literature. Although the majority of reported inductive coupling wireless power transfer (WPT) systems use a class-E power amplifier for driving the primary coil, still there is a lack of a comprehensive study on class-E circuit dedicated to WPT, providing a set of closed form design equations for proper class-E operation. This paper presents the required design equations needed to design a 'true' class-E circuit for WPT applications. Equations for the series-tuned secondary coil WPT system are presented, as well as two different design procedures for the parallel-tuned secondary coil. The derived equations have been... 

    Crashworthiness determination of side doors and B pillar of a vehicle subjected to pole side impact

    , Article Applied Mechanics and Materials ; Vol. 663, issue , 2014 , p. 552-556 Lilehkoohi, A. H ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
    2014
    Abstract
    Pole Side Impact Tes is one out of three crash tests described by Euro NCAP standard for star rating of a vehicle and is required for assessing the Adult Occupant Protection. In this paper the goal is to determine the crashworthiness of side doors and B pillar in a Pole Side Impact Test based on Euro New Car Assessment Program (Euro-NCAP) using computer and simulation method. In this matter, a vehicle model has been prepared and meshed using Hypermesh and CATIA. The velocity of 29 km/h has been assigned to the vehicle which was on top of a cart while the pole has been assigned as a rigid static object based on Euro NCAP requirements specifically. Results show that different amounts of energy... 

    Investigation of Thickness Influences On Energy Absorption For Side Doors And B Pillar In Euro NCAP Pole Side Impact Test

    , Article Applied Mechanics and Materials ; Vol. 663, issue , Oct , 2014 , p. 585-589 Lilehkoohi, A. H ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
    2014
    Abstract
    To assess a car under the Euro New Car Assessment Program (Euro-NCAP), Adult Occupant Protection is one out of three parameters which need to be calculated with a weight factor of 50% while the other parameters, Child Occupant Protection and Pedestrian Occupant Protection, have a weight factor of 20%. The Pole Side Impact Test, beside two other tests, Side and Front Impact, is also required to calculate the Adult Occupant Protection. It shows how important the Pole Side Impact Test is and what an effective role it has in the car rating assessment. In this paper, the objective is to evaluate the effect of thickness on the energy absorbed by the side doors and the B pillar and its... 

    Crashworthiness determination for front and rear doors and B pillar subjected to side impact crash by a mobile deformable barrier

    , Article Advanced Science Letters ; Volume 19, Issue 2 , 2013 , Pages 392-395 ; 19366612 (ISSN) Lilehkoohi, A. H ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
    2013
    Abstract
    In Euro NCAP standard, adult protection is one of the most important rating scores with 50% weight factor while child protection and pedestrian protection are accounted into consideration with 20% weight factor. For adult protection testing, three tests are required to perform: (1) side impact, (2) pole impact, (3) front impact. In the side impact test, dummy's head, chest, shoulder, thorax, ribs, abdomen, pelvic and femur must be studied to evaluate the rating score. Crashworthiness of a car during side impact can describe the score rated for that car. In this paper the goal is to determine the crashworthiness of side doors and B-pillar in side impact crash est by simulation using LS DYNA... 

    Effect of material and thickness of side doors and B pillar on crashworthiness in euro NCAP side impact crash test

    , Article Advanced Science Letters ; Volume 19, Issue 2 , 2013 , Pages 420-424 ; 19366612 (ISSN) Lilehkoohi, A. H ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
    2013
    Abstract
    In side impact test which is one out of three tests of Euro NCAP standard, front and rear doors and B pillar are most absorbance parts among vehicle body parts. Passengers are highly in danger while side crash, because of the distance between passenger's head and vehicle body. In this paper effect of material and thickness of doors and B-pillar and their absorbed energy during crash and improvement of its crashworthiness with respect to light weight design are studied using LS DYNA solver. The objective of this paper is to propose a material for doors and B-pillar with a specified thickness to achieve maximum absorbed energy and minimum weight. The shape of the doors and B-pillar remains... 

    Effect of recycle gas composition of the performance of Fischer-Tropsch catalyst

    , Article Petroleum Science and Technology ; Volume 28, Issue 5 , 2010 , Pages 458-468 ; 10916466 (ISSN) Rohani, A. A ; Khorashe, F ; Safekordi, A. A ; Tavassoli, A ; Sharif University of Technology
    2010
    Abstract
    In this study, the influence of CO2 and CH4 on the performance and selectivity of Co-Ru/Al2O3 catalyst is investigated by injection of these gases (0-20 vol.% of feed) to the feed stream. The effect of temperature and feed flow rate are also inspected. The results show that low amounts of CO2 in the feed stream do not change the catalyst activity, but increasing the amount of CO2 (more than 10 vol.%), causes the CO conversion to decrease and the selectivity of heavy components to increase. Methane acts as an inert gas and does not affect the catalyst performance. Increasing feed flow rate has a negative effect on both CO conversion and heavy component selectivity. By raising the temperature,...