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    Modified Chitosan. 3. Superabsorbency, Salt- and pH-Sensivity of Smart Ampholitic hydrogels from Chitosan-g-PAN [electronic resource]

    , Article Polymers for Advanced Technologies ; Volume 15, Issue 4, pages 173–180, April 2004 Mahdavinia, G. R. (Golam Reza) ; Zohuriaan-Mehr, M. J ; Pourjavadi, M. J
    Abstract
    Polyacrylonitrile (PAN) grafted chitosan was prepared by ceric-initiated graft polymerization of acrylonitrile onto chitosan in a homogenous medium. The copolymer chitosan-g-PAN product was then hydrolyzed to yield a novel smart hydrogel (H-chitoPAN) with superabsorbing properties. The influence of add-on values as well as temperature and time of hydrolysis of the initial chitosan-g-PAN on swelling behavior of the hydrogel was evaluated in water and various salt solutions. The swelling kinetics of the superabsorbing hydrogel was studied as well. The hydrogels exhibited ampholytic and pH-sensitivity characteristics. Several sharp swelling changes were observed in lieu of pH variations in a... 

    Modified carrageenan. 4. Synthesis and swelling behavior of crosslinked kappa C-g-AMPS superabsorbent hydrogel with antisalt and pH-responsiveness properties [electronic resource]

    , Article Journal of Applied Polymer Science ; Vol.98, No.1, 255-263, 2005 Pourjavadi, A. (Ali) ; Hosseinzadeh, H ; Mazidi, R
    Abstract
    To synthesize a novel biopolymer-based superabsorbent hydrogel, 2-acrylamido-2-methylpropanesulfonic acid (AMPS) was grafted onto kappa-carrageenan (KC) backbones. The graft copolymerization reaction was carried out in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator, N,N,N',N'-tetramethyl ethylenediamine (TMEDA) as an accelerator, and N,N'-methylene bisacrylamide (MBA) as a crosslinker. A proposed mechanism for KC-g-AMPS formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy. The affecting variables on swelling capacity, i.e., the initiator, the crosslinker, and the monomer concentration, as well as reaction temperature,... 

    A microfluidic concentration gradient generator for simultaneous delivery of two reagents on a millimeter-sized sample

    , Article Journal of Flow Chemistry ; Volume 10, Issue 4 , 2020 , Pages 615-625 Rismanian, M ; Saidi, M. S ; Kashaninejad, N ; Sharif University of Technology
    Springer International Publishing  2020
    Abstract
    Microfluidic concentration gradient generators (μCGGs) are indispensable parts of many emerging lab-on-a-chip platforms for biological studies and drug delivery applications. Most of the μCGGs reported in the literature can only generate the desired concentration gradients in a micron-sized sample (e.g., cells). As such, there is an unmet need to design a μCGG that can generate continuous concentration gradients of multi reagents (e.g., drugs) in a millimeter-sized sample (e.g., tissue). Herein, we report the proof-of-concept of this class of μCGG by combining a modified tree-like CGG with a micromixer. By conducting both experimental investigation and numerical analysis, we show that the... 

    Modified chitosan III, superabsorbency, salt- and pH-sensitivity of smart ampholytic hydrogels from chitosan-g-PAN

    , Article Polymers for Advanced Technologies ; Volume 15, Issue 4 , 2004 , Pages 173-180 ; 10427147 (ISSN) Mahdavinia, G. R ; Zohuriaan Mehr, M. J ; Pourjavadi, A ; Sharif University of Technology
    John Wiley and Sons Ltd  2004
    Abstract
    Polyacrylonitrile (PAN) grafted chitosan was prepared by ceric-initiated graft polymerization of acrylonitrile onto chitosan in a homogenous medium. The copolymer chitosan-g-PAN product was then hydrolyzed to yield a novel smart hydrogel (H-chitoPAN) with superabsorbing properties. The influence of add-on values as well as temperature and time of hydrolysis of the initial chitosan-g-PAN on swelling behavior of the hydrogel was evaluated in water and various salt solutions. The swelling kinetics of the superabsorbing hydrogel was studied as well. The hydrogels exhibited ampholytic and pH-sensitivity characteristics. Several sharp swelling changes were observed in lieu of pH variations in a... 

    Application of sensitivity analysis to the development of high performance adaptive hydraulic engine mounts

    , Article Vehicle System Dynamics ; Volume 39, Issue 4 , 2003 , Pages 257-278 ; 00423114 (ISSN) Foumani, M. S ; Khajepour, A ; Durali, M ; Sharif University of Technology
    2003
    Abstract
    In this paper, the sensitivity analysis is applied to the development of high performance adaptive hydraulic mounts. The analysis allows us to select the most effective design parameters for tuning an adaptive mount to different road and engine conditions. It is shown that in the low frequency road excitation, the upper chamber compliance and inertia of the fluid column in the inertia track are the most influential properties in changing the dynamic stiffness of the hydraulic mount. These properties for the high frequency engine excitations are the upper compliance and the inertia of the fluid column of the decoupler. For tuning the adaptive mount to different road and engine excitation, a... 

    Effect of dispersion fluctuations on longitudinal gain evolution in phase-sensitive parametric amplifiers

    , Article Optics InfoBase Conference Papers ; 2014 ; ISSN: 21622701 ; ISBN: 9781557529992 Alishahi, F ; Vedadi, A ; Shoaie, M. A ; Soto, M. A ; Denisov, A ; Mehrany, K ; Thevenaz, L ; Bres, C. S ; Sharif University of Technology
    Abstract
    A Brillouin probing method is proposed to extract the distribution of signal power along phase-sensitive parametric amplifiers. Operation near the zero-dispersion-wavelength shows enhanced sensitivity to dispersion fluctuations, allowing effective extraction of the dispersion map  

    Improved efficiency of dye-sensitized solar cells based on a single layer deposition of skein-like TiO 2 nanotubes

    , Article Journal of the American Ceramic Society ; Vol. 97, issue. 9 , 2014 , pp. 2873-2879 ; ISSN: 00027820 Mojaddami, M ; Mohammadi, M. R ; Madaah Hosseini, H. R ; Sharif University of Technology
    Abstract
    We present a new TiO2 morphology, featuring high surface area and open structure, synthesized by a two-step chemical route for the manufacture of dye-sensitized solar cells (DSSCs). This construct is sets of intertwined one-dimensional (1D) nanostructures (i.e., nanotubes), so-called skein-like nanotubes (NTs). Such morphology is produced by a combination of TiC oxidation and hydrothermal processes. The mesoporous TiO2 nanoparticles, as the product of TiC oxidation operation, is used as the precursor of hydrothermal process to grow the skein-like NTs. The effect of processing parameters of TiC oxidation and hydrothermal processes is studied. The skein-like morphology enables to eliminate the... 

    Double-Layer TiO2 Electrodes with Controlled Phase Composition and Morphology for Efficient Light Management in Dye-Sensitized Solar Cells

    , Article Journal of Cluster Science ; Vol. 25, issue. 4 , 2014 , p. 1029-1045 Abdi-Jalebi, M ; Mohammadi, M. R ; Fray, D. J ; Sharif University of Technology
    Abstract
    The light-scattering effect in the dye-sensitized solar cells (DSCs) was studied by controlling TiO2 phase composition and morphology by fabrication of double-layer cells with different arrangement modes. The starting material for preparation of TiO2 cells was synthesized by an aqueous sol-gel process. X-ray diffraction and field emission scanning electron microscopic analyses revealed that TiO2 nanoparticles had particle size ranging between 18 and 44 nm. The optical property and band gap energy of TiO2 nanoparticles were studied through UV-Vis absorption. The indirect optical band gap energy of anatase and rutile nanoparticles was found to be 3.47 and 3.41 eV, respectively. The... 

    Redox-sensitive smart nanosystems for drug and gene delivery

    , Article Current Organic Chemistry ; Volume 20, Issue 28 , 2016 , Pages 2949-2959 ; 13852728 (ISSN) Karimi, M ; Moosavi Basri, S. M ; Vossoughi, M ; Pakchin, P. S ; Mirshekari, H ; Hamblin, M. R ; Sharif University of Technology
    Bentham Science Publishers B.V 
    Abstract
    Background: Smart stimulus-responsive nanocarriers represent a rapidly growing class of drug-delivery systems for cancer and other diseases. Objective: The alterations of redox potential between the intracellular environment and the extracellular space have been widely utilized as a trigger for delivery of therapeutic agents by smart stimulus-responsive nanocarriers. We set out to review the scientific literature. Method: Published papers between 1980 and the present day were surveyed. Results: The advantages of redox-activated smart delivery of drugs, genes, and imaging agents include: the amplitude of the redox-responsive signal; the simple chemical features needed to trigger the... 

    Using geometrical routing for overlay networking in MMOGs

    , Article Multimedia Tools and Applications ; Volume 45, Issue 1-3 , October , 2009 , Pages 61-81 Hariri, B. (Behnoosh) ; Pakravan, M. R. (Mohammad Reza) ; Shirmohammadi, Sh. (Shervin) ; Alavi, H. (Hossein) ; Sharif University of Technology
    Abstract
    At a first glance, transmitting update information to a geographic region in the virtual space seems to be an attractive primitive in Massively Multiplayer Online Gaming (MMOG) applications where players are constantly moving and need to send updates to their neighbors who are in the same region of the virtual space. The system would become more scalable if entities did not need to keep track of each other or send messages directly to one another. Rather, an entity could just send a message to a specific region in the virtual space (its area of effect), as opposed to sending packets to specific IP addresses, significantly reducing tracking and routing overhead. Fundamentally speaking, update... 

    Optimum design of R.O. membrane by using simulation techniques

    , Article Desalination and Water Treatment ; Volume 9, Issue 1-3 , 2009 , Pages 189-194 ; 19443994 (ISSN) Afrasiabi, N ; Ehteshami, M ; Ardakanian, R ; Sharif University of Technology
    2009
    Abstract
    Increasing demand of fresh water, and limitation water resources, with respect to world economic growth brings up the importance of utilization of saline water. At the current research the sensitivity analysis of ROSA was conducted. For this analysis, a single stage reverse osmosis is designed for well water specifi cation in southern Tehran under following condition: Feed fl ow: 40 m3/h and membrane Element: BW30–400 FR. The sensitivity analyses for all chemical element of base water were performed. As a result of sensitivity analysis shortest sensitivity gap, belongs to boron, and longest sensitivity gap, belongs to calcium. Which refl ects, under the same conditions, the least element to... 

    On ontology alignment experiments

    , Article Webology ; Volume 3, Issue 3 , 2006 ; 1735188X (ISSN) Abolhassani, H ; Bagheri Hariri, B ; Haeri, S. H ; Sharif University of Technology
    2006
    Abstract
    Ontology Alignment is a process for finding related entities of different ontologies. This paper discusses the results of our research in this area. One of them is a formulation for a new structural measure which extends famous related works. In this measure with a special attention to the transitive properties, it is tried to increase recall with less harm on precision. Second contribution is a new method for compound measure creation without any need to the mapping extraction phase. Effectiveness of these ideas is discussed and quantitative evaluations are explained in this paper. Copyright © 2006, Hassan Abolhassani, Babak Bagheri Hariri, & Seyed H. Haeri  

    Analytical solution of nonlinear differential equations two oscillators mechanism using Akbari-Ganji method

    , Article Modern Physics Letters B ; Volume 35, Issue 31 , 2021 ; 02179849 (ISSN) Hosseinzadeh, S ; Hosseinzadeh, K ; Rahai, M ; Ganji, D. D ; Sharif University of Technology
    World Scientific  2021
    Abstract
    In the last decade, many potent analytical methods have been utilized to find the approximate solution of nonlinear differential equations. Some of these methods are energy balance method (EBM), homotopy perturbation method (HPM), variational iteration method (VIM), amplitude frequency formulation (AFF), and max-min approach (MMA). Besides the methods mentioned above, the Akbari-Ganji method (AGM) is a highly efficient analytical method to solve a wide range of nonlinear equations, including heat transfer, mass transfer, and vibration problems. In this study, it was constructed the approximate analytic solution for movement of two mechanical oscillators by employing the AGM. In the derived... 

    Sensitivity and generalized analytical sensitivity expressions for quantitative analysis using convolutional neural networks

    , Article Analytica Chimica Acta ; 2021 ; 00032670 (ISSN) Shariat, K ; Kirsanov, D ; Olivieri, A. C ; Parastar, H ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    In recent years, convolutional neural networks and deep neural networks have been used extensively in various fields of analytical chemistry. The use of these models for calibration tasks has been highly effective; however, few reports have been published on their properties and characteristics of analytical figures of merit. Currently, most performance measures for these types of networks only incorporate some function of prediction error. While useful, these measures are incomplete and cannot be used as an objective comparison among different models. In this report, a new method for calculating the sensitivity of any type of neural network is proposed and studied on both simulated and real... 

    Modified carrageenan. 2. Hydrolyzed crosslinked κ -carrageenan-g-PAAm as a novel smart superabsorbent hydrogel with low salt sensitivity

    , Article Journal of Biomaterials Science, Polymer Edition ; Volume 15, Issue 12 , 2004 , Pages 1499-1511 ; 09205063 (ISSN) Hosseinzadeh, H ; Pourjavavdi, A ; Zohuriaan Mehr, M. J ; Sharif University of Technology
    2004
    Abstract
    A novel pH-responsive superabsorbing hydrogel based on κ-carrageenan (κC) was prepared through polyacrylamide crosslinking grafting followed by alkaline hydrolysis. The hydrogel structure was confirmed using FT-IR spectroscopy. The hydrolysis conditions were systematically optimized to obtain a hydrogel with maximum swelling capacity. Thus, the reaction variables, including the hydrolysis time and temperature, concentration of sodium hydroxide, amount of hydrogel hydrolyzed and post-neutralization pH, were optimized. The swelling measurements of the hydrogels were conducted in 0.15 M aqueous solutions of LiCl, NaCl, KCl, CaCl2 and AlCl3. As observed for the hydrolyzed hydrogel (H-carragPAM),... 

    Impact of difference of feeder impedances on the performance of a static transfer switch

    , Article IEEE Transactions on Power Delivery ; Volume 19, Issue 2 , 2004 , Pages 679-685 ; 08858977 (ISSN) Mokhtari, H ; Iravani, M. R ; Sharif University of Technology
    2004
    Abstract
    Conventionally, control system of a static transfer switch (STS) is designed based on the assumption that the STS terminal voltages are in-plane. This paper investigates the impact of phase difference of the STS terminal voltages on the STS transfer time and cross current. The phase difference is assumed to be a result of the difference of the feeder impedances. The paper shows that phase differences of even up to 4.5°, which are accompanied by up to 5% voltage drop at the STS terminal, can noticeably increase the transfer time and the cross current magnitude. The studies are conducted on the IEEE STS-1 benchmark system using the PSCAD/EMTDC software  

    Transient behavior of load transformer during subcycle bus transfer

    , Article IEEE Transactions on Power Delivery ; Volume 18, Issue 4 , 2003 , Pages 1342-1349 ; 08858977 (ISSN) Mokhtari, H ; Iravani, M. R ; Dewan, S. B ; Sharif University of Technology
    2003
    Abstract
    Fast (subcycle) bus transfer by means of a static transfer switch (STS) requires short time intervals for detection and transfer process. Due to these time intervals, the load transformer is subjected to a transient process which can be accompanied by large transient current components through the transformer. The transient current, in turn, can cause voltage sag at the load terminal. The STS control logic must be able to distinguish such a voltage sag from those due to the supply disturbances and not disconnect the load. This paper provides simplified analytical expressions to predict F of the load transformer which can be used to estimate the corresponding voltage sag. PSCAD/EMTDC-based... 

    Superabsorbent hydrogels from starch-g-PAN: Effect of some reaction variables on swelling behavior

    , Article Journal of Polymer Materials ; Volume 20, Issue 1 , 2003 , Pages 113-120 ; 09700838 (ISSN) Zohuriaan Mehr, M. J ; Pourjavadi, A ; Sharif University of Technology
    2003
    Abstract
    Two series of alkali hydrolyzed starch-g-polyacrylonitrile (H-SPAN) superabsorbents were prepared from granular and gelatinized corn starches. The grafting parameters of SPAN copolymers were determined and the polymers were analyzed by FTIR spectroscopy. A combination of three influencing factors (i.e. thermal pre-treatment of the initial starch, presence or absence of oxygen in the stage of ceric-initiated PAN grafting, and neutralization after alkali treatment) on swelling characteristics of the final hydrogel was evaluated in a practical viewpoint. The superabsorbents were discriminated according to their swelling behavior in water and different aqueous salt solutions. The swelling... 

    Performance evaluation of thyristor-based static transfer switch with respect to cross current

    , Article IEEE/PES Transmission and Distribution Conference and Exhibition 2002 : Asia Pacific, Yokahama, 6 October 2002 through 10 October 2002 ; Volume 2, Issue ASIA PACIFIC , 2002 , Pages 1326-1331 Mokhtari, H ; Sharif University of Technology
    2002
    Abstract
    Providing clean, continuous and reliable power to many industrial customers has become a necessity. Where possible, sensitive customers are supplied by two medium-voltage utility feeders one of which is used as back up. Thyristor-based Static Transfer Switches (STSs) are able to provide the loads with a fast transfer to the back up feeder when the main one fails. In addition to being fast, the transfer must be performed with no source paralleling which creates a cross current flowing between the main feeder and the back up one. Due to practical limitations, however, in some cases, cross current cannot be avoided. This paper investigates the performance of thyristor-based STSs with respect to... 

    Estimating aqueous nanofluids viscosity via GEP modeling: Correlation development and data assessment

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 41, Issue 1 , 2022 , Pages 266-283 ; 10219986 (ISSN) Mahdaviara, M ; Rostami, A ; Shahbazi, K ; Shokrollahi, A ; Ghazanfari, M. H ; Sharif University of Technology
    Iranian Institute of Research and Development in Chemical Industries  2022
    Abstract
    This paper focuses on developing a new method that represents user-accessible correlation for the estimation of water-based nanofluids viscosity. For this, an evolutionary algorithm, namely Gene Expression Programming (GEP), was adapted based on a wide selection of literature published databanks including 819 water-based nanofluids viscosity points. The developed model utilized the base fluid viscosity as well as volume fraction and size of the nanoparticles as the inputs of the model. Several statistical parameters integrated with graphical plots were employed in order to assess the accuracy of the proposed GEP-based model. Results of the evaluation demonstrate fairly enough accuracy of the...