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    Gas permeability measurement in polyethylene and its copolymer films

    , Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) Gholizadeh, M ; Razavi, J ; Mousavi, A ; Sharif University of Technology
    2006
    Abstract
    In this research, low density polyethylene (LDPE) and poly ethylene-co-vinyl acetate (EVA) were used as polymeric materials. The methods used to produce LDPE and EVA was Film Blowing and ThermalDry Phase Inversion. The amount of permeability, diffusivity and solubility of O2 and CO2 through above polymers were obtained and also the effect of temperature, pressure and film thickness for LDPE was measured. The Barometric method was considered and measurements were based on ASTM standard. To study film cross-section morphology in EVA, Scanning Electron Microscopy (SEM) was applied. From results we considered that the amount of permeability and solubility were decreased by increasing film... 

    A new linguistic steganography scheme based on lexical substitution

    , Article 2014 11th International ISC Conference on Information Security and Cryptology, ISCISC 2014 ; 2014 , pp. 155-160 ; ISBN: 9781479953837 Yajam, H. A ; Mousavi, A. S ; Amirmazlaghani, M ; Sharif University of Technology
    Abstract
    Recent studies in the field of text-steganography shows a promising future for linguistic driven stegosystems. One of the most common techniques in this field is known as lexical substitution which provides the requirements for security and payload capacity. However, the existing lexical substitution schemes need an enormous amount of shared data between sender and receiver which acts as the stego key. In this paper, we propose a novel encoding method to overcome this problem. Our proposed approach preserves the good properties of lexical substitution schemes while it provides short length stego keys and significant robustness against active adversary attacks. We demonstrate high efficiency... 

    Simplified MAP-MUD for active user CDMA

    , Article IEEE Communications Letters ; Volume 15, Issue 6 , April , 2011 , Pages 599-601 ; 10897798 (ISSN) Pad, P ; Mousavi, A ; Goli, A ; Marvasti, F ; Sharif University of Technology
    2011
    Abstract
    In CDMA systems with variable number of users, the decoder consists of two stages. The first stage is the active user identification and the second one is the multi-user detection. Most of the proposed active user identification methods fail to work in overloaded CDMA systems (when the number of users is more than the spreading factor). In this paper we propose a joint active user identification and multi-user detection for binary input CDMA systems using the Viterbi algorithm. We will show that the proposed identification/detection method is Maximum A posteriori Probability (MAP) and outperforms the pervious results. In addition, some suboptimum decoders will be proposed that have lower... 

    Modeling magneto-mechanical behavior of Fe3O4 nanoparticle/polyamide nanocomposite membrane in an external magnetic field

    , Article Journal of Composite Materials ; Volume 52, Issue 11 , 2018 , Pages 1505-1517 ; 00219983 (ISSN) Tayefeh, A ; Wiesner, M ; Mousavi, A ; Poursalehi, R ; Sharif University of Technology
    SAGE Publications Ltd  2018
    Abstract
    The magnetic response of a polyamide nanocomposite membrane under applying a magnetic field has been modeled to evaluate elastic deformation order of magnitude. A PA-Fe3O4 nanocomposite membrane is considered to be modeled under influence of volume plane stress caused by a magnetic field. The modeling of the mechanical behavior of Fe3O4-PA nanocomposite membrane suggests that nanoparticle displacements within the nanocomposite, in the order of 200 nm under applying an external magnetic field, are greater than free volumes or porosities of the polyamide membrane. The membrane can be excited to mechanically vibrate by applying an alternating magnetic field lower than 0.1 T. As the results... 

    Enzymatically crosslinked hyaluronic acid microgels as a vehicle for sustained delivery of cationic proteins

    , Article European Polymer Journal ; Volume 115 , 2019 , Pages 234-243 ; 00143057 (ISSN) Jooybar, E ; Abdekhodaie, M. J ; Mousavi, A ; Zoetebier, B ; Dijkstra, P. J ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    In this study, a novel biodegradable hyaluronic acid (HA) based microgel were prepared via enzymatic crosslinking of tyramine conjugated HA (HA-TA) in an inverse microemulsion. HA-TA microdroplets were crosslinked within a few seconds in the presence of horseradish peroxidase (HRP) and hydrogen peroxide (H 2 O 2 ). The high water content of the polymeric network and the inherent negative charge of the HA-TA microgels provided a suitable platform for encapsulation of cationic proteins like lysozyme and TGF-β1 growth factor. The results demonstrated that lysozyme was released, after an initial burst release, in a suitable sustained manner over a period of four weeks. Both diffusion and... 

    Efficient embedding of empirically-derived constraints in the ODE formulation of multibody systems: Application to the human body musculoskeletal system

    , Article Mechanism and Machine Theory ; Volume 133 , 2019 , Pages 673-690 ; 0094114X (ISSN) Ehsani, H ; Poursina, M ; Rostami, M ; Mousavi, A ; Parnianpour, M ; Khalaf, K ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    We present a novel method for deriving the governing equations of the musculoskeletal system, a new class of multibody systems in which the constituent components are connected together via anatomical joints which behave differently compared with traditional mechanical joints. In such systems, the kinematics of the joints and the corresponding constraints are characterized experimentally. We generate the equations of motion of these complex systems in which the homogeneous transformation matrices become matrix-valued functions of the generalized coordinate vector due to the empirical expression of body coordinates as smooth functions of generalized coordinates. The detailed mathematical... 

    Azo dye removal via surfactant-assisted polyvinylidene fluoride membrane

    , Article Environmental Health Engineering and Management ; Volume 8, Issue 1 , 2021 , Pages 25-32 ; 24233765 (ISSN) Darbandi, F ; Mousavi, A ; Bagheri Lotfabad, T ; Heydarinasab, A ; Yaghmaei, S ; Sharif University of Technology
    Kerman University of Medical Sciences  2021
    Abstract
    Background: Recently, concerns have been raised regarding the environmental and public health safety of azo dyes, the most widely used synthetic dyes. The membrane technique has been introduced as one of the efficient methods for dye removal treatments. Polyvinylidene fluoride (PVDF) membrane manipulated by surfactants was studied for removal of the azo dye, carmoisine. Methods: PVDF membrane was prepared via non-solvent-induced phase separation (NIPS) and used to remove the azo dye, carmoisine. Three nonionic surfactants including Tween 20, Tween 60, and Tween 80 were used individually as additives in casting solutions to improve PVDF membrane properties. Results: Fourier-transform infrared... 

    An injectable platelet lysate-hyaluronic acid hydrogel supports cellular activities and induces chondrogenesis of encapsulated mesenchymal stem cells

    , Article Acta Biomaterialia ; 2018 ; 17427061 (ISSN) Jooybar, E ; Abdekhodaie, M. J ; Alvi, M ; Mousavi, A ; Karperien, M ; Dijkstra, P. J ; Sharif University of Technology
    Acta Materialia Inc  2018
    Abstract
    Developing scaffolds that can provide cells and biological cues simultaneously in the defect site is of interest in tissue engineering field. In this study, platelet lysate (PL) as an autologous and inexpensive source of growth factors was incorporated into a cell-laden injectable hyaluronic acid-tyramine (HA-TA) hydrogel. Subsequently, the effect of platelet lysate on cell attachment, viability and differentiation of human mesenchymal stem cell (hMSCs) toward chondrocytes was investigated. HA-TA conjugates having a degree of substitution of 20 TA moieties per 100 disaccharide units were prepared and crosslinked in the presence of horseradish peroxidase and low concentrations of hydrogen... 

    Polycarbonate surface cell's adhesion examination after Nd:YAG laser irradiation

    , Article Materials Science and Engineering C ; Volume 29, Issue 4 , 2009 , Pages 1491-1497 ; 09284931 (ISSN) Ramezani Saadat Abadi, A ; Mousavi, A ; Seyedjafari, E ; Poursalehi, R ; Sareh, S ; Silakhori, K ; Poorfatollah, A. A ; Shamkhali, A. N ; Sharif University of Technology
    2009
    Abstract
    Nd:YAG laser treatment was used in order to increase surface cell adhesion aspects of polycarbonate (PC) films prepared via melt process. The treatment was carried out under different wavelengths and beam diameters. ATR-FTIR and UV spectra obtained from different samples before and after laser treatment in air showed that laser irradiation has induced some chemical and physical changes in surface properties. The irradiated films were also characterized using scanning electron microscopy (SEM) and contact angle measurements. Effect of pulse numbers on the surface properties was also investigated. Cell culture test was used to evaluate cell adhesion property on the PC films before and after... 

    Developing hyaluronic acid microgels for sustained delivery of platelet lysate for tissue engineering applications

    , Article International Journal of Biological Macromolecules ; Volume 144 , 2020 , Pages 837-846 Jooybar, E ; Abdekhodaie, M. J ; Karperien, M ; Mousavi, A ; Alvi, M ; Dijkstra, P. J ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    Platelet lysate (PL), a blood product that contains high concentrations of growth factors (GFs), can be considered as a cost-effective source of multiple GFs. In this study, hyaluronic acid (HA) based microgels were developed for delivery of PL proteins. Spherical microgel were prepared using a water in oil emulsion method. First, hyaluronic acid was grafted with tyramine groups, after which prepared microdroplets were crosslinked via an enzymatic reaction in the presence of hydrogen peroxide and horseradish peroxidase. Because of electrostatic interactions, these microgels are promising carriers for positively charged proteins entrapment like most of the GFs. When microgels are incubated in...