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    Encapsulation strategies for highly stable perovskite solar cells under severe stress testing: damp heat, freezing, and outdoor illumination conditions

    , Article ACS Applied Materials and Interfaces ; Volume 13, Issue 38 , 2021 , Pages 45455-45464 ; 19448244 (ISSN) Mohammadi, M ; Gholipour, S ; Malekshahi Byranvand, M ; Abdi, Y ; Taghavinia, N ; Saliba, M ; Sharif University of Technology
    American Chemical Society  2021
    Abstract
    A key direction toward managing extrinsic instabilities in perovskite solar cells (PSCs) is encapsulation. Thus, a suitable sealing layer is required for an efficient device encapsulation, preventing moisture and oxygen ingression into the perovskite layer. In this work, a solution-based, low-cost, and commercially available bilayer structure of poly(methyl methacrylate)/styrene-butadiene (PMMA/SB) is investigated for PSCs encapsulation. Encapsulated devices retained 80% of the initial power conversion efficiency (PCE) at 85 °C temperature and 85% relative humidity after 100 h, while reference devices without SB (only PMMA) suffer from rapid and intense degradation after only 2 h, under the... 

    Effects of alumina nanoparticles on the microstructure, strength and wear resistance of poly (methyl methacrylate)-based nanocomposites prepared by friction stir processing

    , Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 79 , March , 2018 , Pages 246-253 ; 17516161 (ISSN) Aghajani Derazkola, H ; Simchi, A ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    In this study, alumina-reinforced poly(methyl methacrylate) nanocomposites (PMMA/Al2O3) containing up to 20 vol% nanoparticles with an average diameter of 50 nm were prepared by friction stir processing. The effects of nanoparticle volume fraction on the microstructural features and mechanical properties of PMMA were studied. It is shown that by using a frustum pin tool and employing an appropriate processing condition, i.e. a rotational speed of 1600 rpm/min and transverse velocity of 120 mm/min, defect free nanocomposites at microscale with fine distribution of the nanoparticles can successfully been prepared. Mechanical evaluations including tensile, flexural, hardness and impact tests... 

    A new procedure for the fabrication of dissimilar joints through injection of colloidal nanoparticles during friction stir processing: Proof concept for AA6062/PMMA joints

    , Article Journal of Manufacturing Processes ; Volume 49 , 2020 , Pages 335-343 Aghajani Derazkola, H ; Simchi, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    We present a new semi-solid state procedure for efficient joining of dissimilar materials. The process called fed friction stir processing (FFSP) and works based on in-situ injection of colloidal nanoparticles in the welding line during processing. To present the efficiency of the process, friction stir welding of AA6062 aluminum alloy and poly(methyl methacrylate) (PMMA) through injection of alumina nanoparticles is presented. Microstructural features and mechanical characteristics of the weldments are elaborated. It is shown that in-situ feeding of the alumina nanoparticles during FFSP changes the thermo-mechanical regimes of the bonding zone and decreases the thickness of interaction... 

    Experimental and thermomechanical analysis of the effect of tool pin profile on the friction stir welding of poly(methyl methacrylate) sheets

    , Article Journal of Manufacturing Processes ; Volume 34 , 2018 , Pages 412-423 ; 15266125 (ISSN) Aghajani Derazkola, H ; Simchi, A ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    Effects of frustum, cubic and triangle tool pin profiles on the friction stir welding (FSW) of poly(methyl methacrylate) (PMMA) were studied by experimental analysis and thermomechanical simulations. It is shown that employing pins with a low contact surface area form macrocracks and voids along the joint line. Edged-type pins locally stir the polymer and cause tunnel defects which are formed at the root of the joint. In contrast, pins with relatively smooth and large surface area would yield a defect-free weldment if an appropriate processing condition is employed. Mechanical examinations in longitudinal (LS) and transverse (TS) directions indicate that the highest tensile strength (LS = 59... 

    Plasma based surface modication of poly (dimethylsiloxane) electrospun membrane proper for organ-on-a-chip applications

    , Article Scientia Iranica ; Volume 26, Issue 2 , 2019 , Pages 808-814 ; 10263098 (ISSN) Kiyoumarsioskouei, A ; Saidi, M. S ; Moghadas, H ; Firoozabadi, B ; Sharif University of Technology
    Sharif University of Technology  2019
    Abstract
    Electrospun porous membrane; Superhydrophilic surfaces; Superhydrophobic surfaces; Cell culture; Organ on a chip; Flexible membrane; Strong membrane; Surface modications  

    Plasma based surface modication of poly (dimethylsiloxane) electrospun membrane proper for organ-on-a-chip applications

    , Article Scientia Iranica ; Volume 26, Issue 2 , 2019 , Pages 808-814 ; 10263098 (ISSN) Kiyoumarsioskouei, A ; Saidi, M. S ; Moghadas, H ; Firoozabadi, B ; Sharif University of Technology
    Sharif University of Technology  2019
    Abstract
    onstructing of the scaffolds for cell culture applications has long been of interest for engineering researchers and biologist. In this study, a novel process is utilized for construction of suitable membrane with a high mechanical strength and appropriate surface behavior. Poly (dimethylsiloxane) (PDMS) is electrospun into fine fibers using poly (methyl methacrylate) (PMMA) as the carrier polymer in different weight ratios. Since the surface behavior of all PDMS substrates is moderately hydrophobic (120 < contact angle (CA) < 150), the electrospun membranes with higher PDMS ratios show slightly higher hydrophilicity. Direct plasma treatment is utilized to change the interfacial wettability... 

    Synthesis and characterization of bagasse poly(methyl methacrylate) graft copolymer

    , Article Macromolecular Symposia ; Volume 274, Issue 1 , 2008 , Pages 49-54 ; 10221360 (ISSN) Sarvi, I ; Pourjavadi, A ; Noei Aghaei, M. A ; Sharif University of Technology
    2008
    Abstract
    Graft copolymerization of methyl methacrylate (MMA) was carried out on bagasse fibers in an aqueous medium using eerie ammonium nitrate (CAN) as initiator under a neutral atmosphere. In order to obtain the optimum condition for graft copolymerization, the effects of initiator concentration, temperature, time of reaction, and monomer concentration were studied. The maximum grafting percent was found to be 122%. The bagasse grafted poly(methyl methacrylate) was characterized by FTIR and its thermal behavior was characterized by TGA. Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA  

    A new detection chamber design on centrifugal microfluidic platform to measure hemoglobin of whole blood

    , Article SLAS Technology ; Volume 26, Issue 4 , 2021 , Pages 392-398 ; 24726303 (ISSN) Mahmodi Arjmand, E ; Saadatmand, M ; Eghbal, M ; Bakhtiari, M. R ; Mehraji, S ; Sharif University of Technology
    SAGE Publications Inc  2021
    Abstract
    Undoubtedly, microfluidics has been a focal point of interdisciplinary science during the last two decades, resulting in many developments in this area. Centrifugal microfluidic platforms have good potential for use in point-of-care devices because they take advantage of some intrinsic forces, most notably centrifugal force, which obviates the need to any external driving forces. Herein, we introduce a newly designed detection chamber for use on microfluidic discs that can be employed as an absorbance readout step in cases where the final solution has a very low viscosity and surface tension. In such situations, our chamber easily eliminates the air bubbles from the final solution without... 

    Nanotechnology-assisted microfluidic systems: From bench to bedside

    , Article Nanomedicine ; Volume 16, Issue 3 , 2021 , Pages 237-258 ; 17435889 (ISSN) Rabiee, N ; Ahmadi, S ; Fatahi, Y ; Rabiee, M ; Bagherzadeh, M ; Dinarvand, R ; Bagheri, B ; Zarrintaj, P ; Saeb, M. R ; Webster, T. J ; Sharif University of Technology
    Future Medicine Ltd  2021
    Abstract
    With significant advancements in research technologies, and an increasing global population, microfluidic and nanofluidic systems (such as point-of-care, lab-on-a-chip, organ-on-a-chip, etc) have started to revolutionize medicine. Devices that combine micron and nanotechnologies have increased sensitivity, precision and versatility for numerous medical applications. However, while there has been extensive research on microfluidic and nanofluidic systems, very few have experienced wide-spread commercialization which is puzzling and deserves our collective attention. For the above reasons, in this article, we review research advances that combine micro and nanotechnologies to create the next... 

    A selective chemiresistive sensor for the cancer-related volatile organic compound hexanal by using molecularly imprinted polymers and multiwalled carbon nanotubes

    , Article Microchimica Acta ; Volume 186, Issue 3 , 2019 ; 00263672 (ISSN) Janfaza, S ; Banan Nojavani, M ; Nikkhah, M ; Alizadeh, T ; Esfandiar, A ; Ganjali, M. R ; Sharif University of Technology
    Springer-Verlag Wien  2019
    Abstract
    A chemiresistive sensor is described for the lung cancer biomarker hexanal. A composite consisting of molecularly imprinted polymer nanoparticles and multiwalled carbon nanotubes was used in the sensor that is typically operated at a voltage of 4 V and is capable of selectively sensing gaseous hexanal at room temperature. It works in the 10 to 200 ppm concentration range and has a 10 ppm detection limit (at S/N = 3). The sensor signal recovers to a value close to its starting value without the need for heating even after exposure to relatively high levels of hexanal  

    Gut-on-a-chip: Current progress and future opportunities

    , Article Biomaterials ; Volume 255 , 2020 Ashammakhi, N ; Nasiri, R ; Barros, N. R. D ; Tebon, P ; Thakor, J ; Goudie, M ; Shamloo, A ; Martin, M. G ; Khademhosseni, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Organ-on-a-chip technology tries to mimic the complexity of native tissues in vitro. Important progress has recently been made in using this technology to study the gut with and without microbiota. These in vitro models can serve as an alternative to animal models for studying physiology, pathology, and pharmacology. While these models have greater physiological relevance than two-dimensional (2D) cell systems in vitro, endocrine and immunological functions in gut-on-a-chip models are still poorly represented. Furthermore, the construction of complex models, in which different cell types and structures interact, remains a challenge. Generally, gut-on-a-chip models have the potential to... 

    Fabrication and characterization of low-cost, bead-free, durable and hydrophobic electrospun membrane for 3D cell culture

    , Article Biomedical Microdevices ; Volume 19, Issue 4 , 2017 ; 13872176 (ISSN) Moghadas, H ; Saidi, M. S ; Kashaninejad, N ; Kiyoumarsioskouei, A ; Trung Nguyen, N ; Sharif University of Technology
    Abstract
    This paper reports the fabrication of electrospun polydimethylsiloxane (PDMS) membranes/scaffolds that are suitable for three-dimensional (3D) cell culture. Through modification the ratio between PDMS and polymethylmethacrylate (PMMA) as carrier polymer, we report the possibility of increasing PDMS weight ratio of up to 6 for electrospinning. Increasing the PDMS content increases the fiber diameter, the pore size, and the hydrophobicity. To our best knowledge, this is the first report describing beads-free, durable and portable electrospun membrane with maximum content of PDMS suitable for cell culture applications. To show the proof-of-concept, we successfully cultured epithelial lung... 

    Recent progress in inorganic and composite coatings with bactericidal capability for orthopaedic applications

    , Article Nanomedicine: Nanotechnology, Biology, and Medicine ; Volume 7, Issue 1 , Feb , 2011 , Pages 22-39 ; 15499634 (ISSN) Simchi, A ; Tamjid, E ; Pishbin, F ; Boccaccini, A. R ; Sharif University of Technology
    Abstract
    This review covers the most recent developments of inorganic and organic-inorganic composite coatings for orthopedic implants, providing the interface with living tissue and with potential for drug delivery to combat infections. Conventional systemic delivery of drugs is an inefficient procedure that may cause toxicity and may require a patient's hospitalization for monitoring. Local delivery of antibiotics and other bioactive molecules maximizes their effect where they are required, reduces potential systemic toxicity and increases timeliness and cost efficiency. In addition, local delivery has broad applications in combating infection-related diseases. Polymeric coatings may present some... 

    Polyamide/titania hollow nanofibers prepared by core–shell electrospinning as a microextractive phase in a fabricated sandwiched format microfluidic device

    , Article Journal of Chromatography A ; Volume 1528 , 2017 , Pages 1-9 ; 00219673 (ISSN) Rezvani, O ; Hashemi Hedeshi, M ; Bagheri, H ; Sharif University of Technology
    Abstract
    In this study, a low–cost microfluidic device from polymethyl methacrylate was fabricated by laser engraving technique. The device is consisted of a central chip unit with an aligned microchannel. Both sides of the engraved microchannel were sandwiched by two synthesized sheets from polyamide/titania (PA/TiO2) hollow nanofibers as extractive phases. The inlet and outlet of the device were connected to the polyether ether ketone tubes, while a peristaltic pump was used to deliver both sample and desorbing solvent through the microchannel. The recorded scanning electron microscopy images from the surface of the synthesized PA/TiO2 nanofibers, exhibit a good degree of homogeneity and porosity...