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    Effect of nanoclays on the mechanical properties and durability of novolac phenolic resin/woven glass fiber composite at various chemical environments

    , Article Composites Part A: Applied Science and Manufacturing ; Vol. 63 , 2014 , pp. 149-158 ; ISSN: 1359835X Eesaee, M ; Shojaei, A ; Sharif University of Technology
    Both natural montmorilonite (CN) and organically modified montmorilonite (CB) improved significantly the mechanical performance of novolac phenolic resin (PF)/woven glass-fiber (GF) composites due to their nanodispersion and good interfacial interaction with the matrix. It was revealed that the incorporation of 2.5 wt% of the clays enhances the elastic modulus up to 38% for CN and 43% for CB. Aging of PF/GF composites at various aqueous solutions, i.e. water, brine and acidic environments, increased stiffness of the composite (∼100-250% increase in elastic modulus) due to possible secondary crosslinking caused by water molecules and hydroxyl groups of PF resin. However, aging led to the... 

    Adsorptive stripping differential pulse voltammetric determination of mebendazole at a graphene nanosheets and carbon nanospheres/chitosan modified glassy carbon electrode

    , Article Sensors and Actuators, B: Chemical ; Volume 185 , 2013 , Pages 669-674 ; 09254005 (ISSN) Ghalkhani, M ; Shahrokhian, S ; Sharif University of Technology
    For the first time graphene nanosheets and carbon nanospheres/chitosan (GNS-CNS/CS) based nanocomposite film modified electrode was used for the electro-oxidation of mebendazole (MD). MD is a benzimidazole drug that is used to treat human infections caused by parasitic worms. MD causes slow immobilization and death of the worms by selectively and irreversibly blocking uptake of glucose. The electrochemical behavior of MD at GNS-CNS/CS modified glassy carbon electrode has been investigated using cyclic and differential pulse voltammetry in aqueous media at different pHs. The prepared electrode showed an excellent electrochemical activity toward the electro-oxidation of MD leading to a... 

    A comparative study on WAS, SWAS, and solvent-soak scenarios applied to heavy-oil reservoirs using five-spot glass micromodels

    , Article Journal of Canadian Petroleum Technology ; Volume 51, Issue 5 , 2012 , Pages 383-392 ; 00219487 (ISSN) Farzaneh, S. A ; Dehghan, A. A ; Ghazanfari, M. H ; Kharrat, R ; Sharif University of Technology
    In this work, a series of solvent- and water-injection scenarios were conducted on horizontal five-spot glass micromodels that were saturated initially with heavy oil. Sandstone and limestone rock look-alike and network patterns with different pore structures were used in the experiments. The results show that the ultimate oil recovery of a water-alternating-solvent (WAS) scheme was greater than that of a simultaneously water-alternating-solvent (SWAS) scheme, and the efficiency of a solvent-soak scheme also offers a greater recovery. Likewise, the WAS scheme resulted in greater oil recovery when compared with continuous solvent injection (CSI), with the same amount of solvent consumption.... 

    Pore-Level Observation of Free Gravity Drainage of Oil in Fractured Porous Media

    , Article Transport in Porous Media ; Volume 87, Issue 2 , 2011 , Pages 561-584 ; 01693913 (ISSN) Mashayekhizadeh, V ; Ghazanfari, M. H ; Kharrat, R ; Dejam, M ; Sharif University of Technology
    This work presents results from two sets of experiments conducted to study, in pore level, the role of fracture aperture and tilt angle on the stability of liquid bridges and the shape of a front during free gravity drainage process. Glass micromodels of two different aperture sizes were used to monitor the mechanism of gravity drainage of air-crude oil system, rotating around a bottom corner to create different tilting angles. Oil content within the matrix blocks was determined as a function of time using a series of images obtained during the experiments, from which net drainage rate from the upper and lower matrix blocks is calculated. Liquid bridges are more frequent but less stable at... 

    Application of glassy carbon electrode modified with a carbon nanoparticle/melamine thin film for voltammetric determination of raloxifene

    , Article Journal of Electroanalytical Chemistry ; Volume 780 , 2016 , Pages 126-133 ; 15726657 (ISSN) Shahrokhian, S ; Ghalkhani, M ; Balotf, H ; Salimian, R ; Sharif University of Technology
    Elsevier B.V  2016
    As a selective estrogen receptor modulator, raloxifene (RXF) prevent of osteoporosis in postmenopausal women by estrogenic actions on bone and decreases the risk of invasive breast cancer by anti-estrogenic actions on the breast and uterus tissue. However, RXF may increase the risk of blood clots, including deep vein thrombosis and pulmonary embolism. For the first time glassy carbon electrode modified with a thin film of melamine/carbon nanoparticles (CNPs/Mela) was constructed and used for the sensitive voltammetric determination of RXF. In comparison with unmodified electrode, the presence of the CNPs/Mela film resulted in a remarkable increase in the peak currents and sharpness of the... 

    Finemet nanocrystalline soft magnetic alloy: Investigation of glass forming ability, crystallization mechanism, production techniques, magnetic softness and the effect of replacing the main constituents by other elements

    , Article Journal of Magnetism and Magnetic Materials ; Volume 408 , 2016 , Pages 177-192 ; 03048853 (ISSN) Gheiratmand, T ; Madaah Hosseini, H. R ; Sharif University of Technology
    Elsevier  2016
    Finemet soft magnetic alloy has been in the focus of interest in the last years due to its high saturation magnetization, high permeability and low core loss. The great quantity of papers has been devoted to the study of its structural and magnetic properties, confirms this claim. This paper reviews the different researches performed on Finemet up to now. The criteria that should be satisfied in order to have the high glass forming ability in an alloy and also the techniques applied for production of Finemet ribbons, powders and bulk samples have been explained. In addition, the mechanism of devitrification, nanocrystallization and magnetic softness in this applicable magnetic alloy has been... 

    Structural modification through pressurized sub-Tg annealing of metallic glasses

    , Article Journal of Applied Physics ; Volume 122, Issue 21 , 2017 ; 00218979 (ISSN) Foroughi, A ; Ashuri, H ; Tavakoli, R ; Stoica, M ; Ažopu, D ; Eckert, J ; Sharif University of Technology
    The atomic structure of metallic glasses (MGs) plays an important role in their physical and mechanical properties. Numerous molecular dynamics (MD) simulations have been performed to reveal the structure of MGs at the atomic scale. However, the cooling rates utilized in most of the MD simulations (usually on the order of 109-1012 K/s) are too high to allow the structure to relax into the actual structures. In this study, we performed long-term pressurized sub-Tg annealing for up to 1 μs using MD simulation to systematically study the structure evolution of Cu50Zr50 MG. We find that from relaxation to rejuvenation, structural excitation of MGs and transition during sub-Tg annealing depend on... 

    Experiments and probabilistic models of bond strength between GFRP bar and different types of concrete under aggressive environments

    , Article Construction and Building Materials ; Volume 148 , 2017 , Pages 429-443 ; 09500618 (ISSN) Bazli, M ; Ashrafi, H ; Vatani Oskouei, A ; Sharif University of Technology
    Bond durability of FRP bars and concrete is an important issue to the overall integrity and long-term performance of a strengthening structure. This paper examines the bond durability of GFRP bars embedded in different types of concrete (Normal, self-compacting, light weight, and high strength) exposed to aggressive environments, namely, sea water, alkaline, and acid. A total of 132 specimens were tested in direct pull-out. The development lengths of both control and conditioned specimens were obtained and compared to the current standards. The results revealed bond strength reductions of 0–21% for the light weight, 1–16% for the normal, 5–9% for the high strength, and 4–12% for the... 

    Glassy carbon electrode modified with 3D graphene–carbon nanotube network for sensitive electrochemical determination of methotrexate

    , Article Sensors and Actuators, B: Chemical ; Volume 239 , 2017 , Pages 617-627 ; 09254005 (ISSN) Asadian, E ; Shahrokhian, S ; Iraji Zad, A ; Ghorbani Bidkorbeh, F ; Sharif University of Technology
    Elsevier B.V  2017
    In the present study, a 3D porous graphene-carbon nanotube (G-CNT) network is successfully constructed on the surface of glassy carbon electrode (GCE) by electrochemical co-deposition from a concentrated graphene dispersion. The large accessible surface area provided by the interpenetrated graphene backbone in one hand and the enhanced electrical conductivity of the 3D network by incorporating CNTs on the other hand, dramatically improved the electrochemical performance of GCE in determination of Methotrexate (MTX) as an important electroactive drug compound. Under the optimum conditions, the electrode modification led to a significant increase in the anodic peak current (∼25 times) along... 

    Gain ripple minimization in the wide-band SCISSOR raman amplifier

    , Article Optics Communications ; Volume 282, Issue 8 , 2009 , Pages 1648-1653 ; 00304018 (ISSN) Bahrampour, A. R ; Bazouband, F ; Sharif University of Technology
    A side coupled integrated spaced sequence (SCISSOR) of Silicon or Chalcogenide glass microrings of different diameter are considered as a wide-band Raman amplifier. Because the two-photon absorption (TPA) losses in Chalcogenide glass are less than that of Silicon, it is shown that Chalcogenide microrings are suitable for wide-band Raman amplifier in the telecommunication bandwidth (1.5 μm). The Lagrange unknown multiplier method is employed to minimize the gain ripple of the amplifier versus the pump and system parameters. Crown Copyright © 2008  

    The effect of particle size on the structural, magnetic and electrical properties of La0.9Ba0.1MNO3 manganite samples

    , Article Phase Transitions ; Volume 92, Issue 11 , 2019 , Pages 949-959 ; 01411594 (ISSN) Shogh, S ; Eshraghi, M ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    In this work, the magnetic and transport properties of micro and nanometer-sized samples of La0.9Ba0.1MnO3 manganite have been studied. The temperature variation of ac susceptibility of the nanometer-sized sample shows one transition at high temperature (265 K). On the contrary, the ac susceptibility of the micrometer-sized sample shows two transitions with a high-temperature transition occurring at 240 K and low-temperature transition around 100 K. The high-temperature transition corresponds to the paramagnetic-ferromagnetic (PM–FM) transition (Tc) and is independent of frequency, while the low-temperature transition is frequency-dependent and shifts toward high temperatures by increasing... 

    Interaction of glazing parameters, climatic condition and interior shadings: performing energy and cost analysis in a residential building in Iran

    , Article Energy Efficiency ; Volume 13, Issue 1 , 21 December , 2020 , Pages 159-176 Yousefi, F ; Gholipour, Y ; Saboohi, Y ; Yan, W ; Sharif University of Technology
    Springer  2020
    In this paper, the interaction between various window specifications and different climate conditions is investigated. For this purpose, simultaneous effects of several aspects including glazing system, glass type, filling gas, glass thickness, window frame fraction, and interior shading are considered under three different climatic conditions. To evaluate the energy performance of various considered alternatives, the energy simulation of a base case building is evaluated in a computer environment. Using the validated model, the energy analysis is quantitatively performed, and cost-benefit analyses from the viewpoints of both residents and government are carried out based on the domestic and... 

    Performance characterization of composite materials based on recycled high-density polyethylene and ground tire rubber reinforced with short glass fibers for structural applications

    , Article Journal of Applied Polymer Science ; Volume 104, Issue 1 , 2007 , Pages 1-8 ; 00218995 (ISSN) Shojaei, A ; Yousefian, H ; Saharkhiz, S ; Sharif University of Technology
    This study addresses the issue of using recycled materials to obtain low-cost structural products for practical applications. Through the use and re-extrusion of virgin high-density polyethylene (HDPE), the effects of the degradation level of HDPE as a matrix phase on its mechanical properties and the mechanical performance of composites produced with the degraded polyethylene have been examined. The degradation level of HDPE caused by reextrusion has been evaluated by the measurement of the melt flow index and mechanical properties of virgin and degraded HDPEs. The results indicate that the modulus and strength of HDPE significantly increase with the addition of polypropylene filled with 30... 

    Micro-scale evolution of mechanical properties of glass-ceramic sealant for solid oxide fuel/electrolysis cells

    , Article Ceramics International ; Volume 47, Issue 3 , 2021 , Pages 3884-3891 ; 02728842 (ISSN) Fakouri Hasanabadi, M ; Malzbender, J ; Groß Barsnick, S. M ; Abdoli, H ; Kokabi, A. H ; Faghihi Sani, M. A ; Sharif University of Technology
    Elsevier Ltd  2021
    The structural integrity of the sealant is critical for the reliability of solid oxide cells (SOCs) stacks. In this study, elastic modulus (E), hardness (H) and fracture toughness (KIC) of a rapid crystallizing glass of BaO–CaO–SiO2 system termed “sealant G” are reported as determined using an indentation test method at room temperature. A wide range of indentation loads (1 mN–10 N) was used to investigate the load-dependency of these mechanical properties. Values of 95 ± 12 GPa, 5.8 ± 0.2 GPa and 1.15 ± 0.07 MPa m0.5 were derived for E, H and KIC using the most suitable indentation loads. An application relevant annealing treatment of 500 h at 800 °C does not lead to a significant change of... 

    Longitudinal quantitative assessment of covid-19 infection progression from chest CTs

    , Article 24th International Conference on Medical Image Computing and Computer Assisted Intervention, MICCAI 2021, 27 September 2021 through 1 October 2021 ; Volume 12907 LNCS , 2021 , Pages 273-282 ; 03029743 (ISSN); 9783030872335 (ISBN) Kim, S. T ; Goli, L ; Paschali, M ; Khakzar, A ; Keicher, M ; Czempiel, T ; Burian, E ; Braren, R ; Navab, N ; Wendler, T ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Chest computed tomography (CT) has played an essential diagnostic role in assessing patients with COVID-19 by showing disease-specific image features such as ground-glass opacity and consolidation. Image segmentation methods have proven to help quantify the disease and even help predict the outcome. The availability of longitudinal CT series may also result in an efficient and effective method to reliably assess the progression of COVID-19, monitor the healing process and the response to different therapeutic strategies. In this paper, we propose a new framework to identify infection at a voxel level (identification of healthy lung, consolidation, and ground-glass opacity) and visualize the... 

    The non-linear effect of oil polarity on the efficiency of low salinity waterflooding: A pore-level investigation

    , Article Journal of Molecular Liquids ; January , 2021 ; 01677322 (ISSN) Golmohammadi, M ; Mohammadi, S ; Mahani, H ; Ayatollahi, S ; Sharif University of Technology
    Elsevier B. V  2021
    Oil polarity is an important property impacting the efficiency of low salinity waterflooding (LSWF). It directly affects fluid/fluid and rock/fluid interactions, controlling the interfacial properties and forces. However, the current findings in the literature on the effect of concentration of polar components on oil recovery by LSWF are contradictory. Therefore, the main objective of this paper is to investigate how the type of non-polar fractions and the concentration of acidic polar oil constituents change the trapped oil saturation at the pore-scale during LSWF. In this regard, we conducted a series of microfluidics LSWF experiments in both secondary and tertiary modes, using clay-free... 

    Characterization of etched glass surfaces by wave scattering

    , Article Surface and Interface Analysis ; Volume 37, Issue 7 , 2005 , Pages 641-645 ; 01422421 (ISSN) Jafari, G. R ; Mahdavi, S. M ; Iraji Zad, A ; Kaghazchi, P ; Sharif University of Technology
    The roughness of glass surfaces after different stages of etching is investigated by reflection measurements with a spectrophotometer, light scattering, atomic force microscopy (AFM, on a small scale) and profilometry (on a large scale). The results suggest that there are three regimes during etching, according to their optical reflectivity and roughness. The first and the second regimes are studied by the Kirchhoff theory and the third one is studied by the optical geometric theory. Also, the roughness obtained by optical scattering is compared with the AFM results. Copyright © 2005 John Wiley & Sons, Ltd  

    Influence of Microstructure on Mechanical Properties and Fracture Behavior of Hybrid PP/GF/CaCO3 Composites

    , M.Sc. Thesis Sharif University of Technology Tabatabaei Ardakani, Ramin (Author) ; Ekrami, Ali Akbar (Supervisor) ; Bagheri, Reza (Supervisor)
    Homo-polymer of Polypropylene is a commodity thermoplastic with good physical and mechanical properties along with fair recyclability and cost. However, its application is limited in some cases, especially in automotive industry, due to a lack of toughness. One of the approaches for PP toughening is the copolymerization of PP with some ethylene co-monomers. However, existence of elastomers in this kind of polymers causes a decrease in tensile properties. Besides, glass fibers improve tensile properties of homo-and co-PP and decrease toughness of co-polymers but result in an increase for homo-polymers. A rise in expenditure of energy due to increasing the processing temperature and... 

    Experimental Investigation of Mechanical Behavior of Structural Concrete with Combination of Waste Glass and Silica Fume

    , M.Sc. Thesis Sharif University of Technology Faghihi, Kamyar (Author) ; Khaloo, Ali Reza (Supervisor)
    Concrete is the second most structural material in the world. So attention and promotion of the concrete mix design with respect to variable issues and requirements, is very important. On the other hand, these days environment and its pollution has become very popular discussion. Waste-glass which is produced by human products is one of the environmental pollutants. In this thesis it replaces some aggregate in concrete and it can reduce the level of this material in the world. Also we study effects of silica-fume as cement replacement and properties enhancer in our concrete mix design and see how it can ... 

    Chitosan–Bioactive Glass Composite Coating on Nd-Fe-B Magnetic Alloy Substrate by Electrophoretic Deposition

    , M.Sc. Thesis Sharif University of Technology Mehdipour, Mehrad (Author) ; Afshar, Abdollah (Supervisor)
    This research work deals with application of poly-saccharide to improve coating process of bioactive ceramic composite on aNd-Fe-B magnetic alloy substrate. Bioactive glass particles were synthesized through a sol-gel process and coated in the form of composite with poly-saccharide onto a magnetic substrate by electrophoretic deposition technique. Stable suspensions of 0.5 gr/lit polysaccharide polymer-ceramic were prepared using bioactive glass particles (<1µm), acetic acid 1%. The influence of added water to ethanol, pH and tri-ethanol-amine (TEA) additive on suspension stability, deposition rate and coating’s structure was investigated. It was shown that by increasing the water to ethanol...