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    Al-Al3Ti nanocomposite produced in situ by two-step hot-press sintering

    , Article IOP Conference Series: Materials Science and Engineering ; Volume 40, Issue 1 , 2012 ; 17578981 (ISSN) Nikfar, B ; Ghiabakloo, H ; Hosseini, H. R. M ; Mohammadi, A. V ; Sharif University of Technology
    2012
    Abstract
    Aluminum reinforced with a large amount (up to about 55 vol.%) of Al 3Ti particles can be fabricated from Al-20Ti elemental nanometer-sized powder mixture via in-situ two step hot press sintering (TSS). For production of intermetallic reinforced in-situ composite, TSS can provide elevated temperature to facilitate the formation of intermetallic phase in situ and hot consolidation to form a fully dense solid. The first step sintering was employed at a higher temperature to obtain an initial high density, and the second step was held at a lower temperature by isothermal sintering for more time than the first one to increase bulk density without significant grain growth. The optimum TSS regime... 

    Densification and properties of ZrO2 nanoparticles added magnesia–doloma refractories

    , Article Ceramics International ; Volume 42, Issue 14 , 2016 , Pages 15658-15663 ; 02728842 (ISSN) Ghasemi Kahrizsangi, S ; Barati Sedeh, M ; Gheisari Dehsheikh, H ; Shahraki, A ; Farooghi, M ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    In this work the effect of nano- and microZrO2 addition on the densification and hydration resistance of MgO–CaO refractories was investigated. 0, 2, 4, 6 and 8 wt% ZrO2 was added to MgO–CaO refractories that contain 35 wt% CaO. The crystalline phases and microstructure characteristics of specimens sintered at 1650 °C for 5 h in an electric furnace were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The physical properties are reported in terms of bulk density, apparent porosity and hydration resistance. Results show that with addition of ZrO2 the bulk density and hydration resistance of the samples increased while apparent porosity decreased. Also... 

    Analysis of cross correlations between well logs of hydrocarbon reservoirs

    , Article Transport in Porous Media ; Volume 90, Issue 2 , 2011 , Pages 445-464 ; 01693913 (ISSN) Dashtian, H ; Jafari, G. R ; Lai, Z. K ; Masihi, M ; Sahimi, M ; Sharif University of Technology
    Abstract
    We carry out a series of cross-correlation analysis of raw well-log data, in order to study the possible connection between natural gamma ray (GR) logs and other types of well logs, such as neutron porosity (NPHI), sonic transient time (denoted usually by DT), and bulk density (RHOB) of oil and gas reservoirs. Three distinct, but complementary, methods are used to analyze the cross correlations, namely, the multifractal detrended cross-correlation analysis (MF-DXA), the so-called Qcc(m) test in conjunction with the statistical test-the χ2(m) distribution-and the cross-wavelet transform (XWT) and wavelet coherency. The Qcc(m) test and MF-DXA are used to identify and quantify the strength of... 

    Current scenario of the tehran municipal solid waste handling rules towards green technology

    , Article International Journal of Environmental Research and Public Health ; Volume 16, Issue 6 , 2019 ; 16617827 (ISSN) Rupani, P. F ; Maleki Delarestaghi, R ; Asadi, H ; Rezania, S ; Park, J ; Abbaspour, M ; Shao, W ; Sharif University of Technology
    MDPI AG  2019
    Abstract
    This study aims to study the waste management process and recycling of municipal waste in Tehran. Currently, Kahrizak is the defined landfill area which collects the waste generated from 22 districts of Tehran. The organic wastes undergo to the windrow composting method in order to manage the partial of the waste generated in the city. Samples from the compost pile generated in Kahrizak were examined to evaluate its fertilizer value to be used further by the farmers. The results show that the obtained compost does not reach the acceptable quality to be used further in agriculture, due to lack of homogeneity, aeration and presence of heavy metals. Overall, it has been concluded that, due to... 

    Identification of catecholamine neurotransmitters using a fluorescent electronic tongue

    , Article ACS Chemical Neuroscience ; Volume 11, Issue 1 , November , 2020 , Pages 25-33 Jafarinejad, S ; Bigdeli, A ; Ghazi Khansari, M ; Sasanpour, P ; Hormozinezhad, M. R ; Sharif University of Technology
    American Chemical Society  2020
    Abstract
    Catecholamine neurotransmitters, specifically, dopamine (DA), epinephrine (EP), and norepinephrine (NE), are known as substantial indicators of various neurological diseases. Developing rapid detection methods capable of simultaneously screening their concentrations is highly desired for early clinical diagnosis of such diseases. To this aim, we have designed an optical sensor array using three fluorescent dyes with distinct emission bands and have monitored variations in their emission profiles upon the addition of DA, EP, and NE in the presence of gold ions. Because of the different reducing power of catecholamines, differently sized gold nanoparticles (GNPs) with different levels of... 

    Scaling, multifractality, and long-range correlations in well log data of large-scale porous media

    , Article Physica A: Statistical Mechanics and its Applications ; Vol. 390, issue. 11 , June , 2011 , p. 2096-2111 ; ISSN: 03784371 Dashtian, H ; Jafari, G. R ; Sahimi, M ; Masihi, M ; Sharif University of Technology
    Abstract
    Three distinct methods, namely, the spectral density, the multifractal random walk approach, and the multifractal detrended fluctuation analysis are utilized to study the properties of four distinct types of well logs from three oil and gas fields, namely, the natural gamma ray emission, neutron porosity, bulk density, and the sonic transient time logs. Such well logs have never been analyzed by the methods that we utilize in the present study. The results indicate that the well logs exhibit multifractal characteristics, and the estimated Hurst exponents by the three methods are close to each other. Using multifractal detrended fluctuation analysis and the shuffled and surrogated data, we... 

    Production of waste bio-fiber cement-based composites reinforced with nano-SiO 2 particles as a substitute for asbestos cement composites

    , Article Construction and Building Materials ; Volume 31 , 2012 , Pages 105-111 ; 09500618 (ISSN) Hosseinpourpia, R ; Varshoee, A ; Soltani, M ; Hosseini, P ; Ziaei Tabari, H ; Sharif University of Technology
    2012
    Abstract
    The environmental impact of asbestos fibers on human health and their consequent safety-related problems indicate that there is a significant need to replace this material in all asbestos-containing products. Many different types of fibers have been introduced to replace asbestos fibers. In this study, the performance of silica nano-particles combined with waste paper pulp fibers (sulfite fibers) has been investigated. Different mechanical (compressive and flexural strengths and bending performance), durability (water absorption), physical (bulk density and flowability), and microstructural (scanning electron microscopy) tests were conducted to examine the properties of manufactured green... 

    Scaling, multifractality, and long-range correlations in well log data of large-scale porous media

    , Article Physica A: Statistical Mechanics and its Applications ; Volume 390, Issue 11 , 2011 , Pages 2096-2111 ; 03784371 (ISSN) Dashtian, H ; Jafari, G. R ; Sahimi, M ; Masihi, M ; Sharif University of Technology
    2011
    Abstract
    Three distinct methods, namely, the spectral density, the multifractal random walk approach, and the multifractal detrended fluctuation analysis are utilized to study the properties of four distinct types of well logs from three oil and gas fields, namely, the natural gamma ray emission, neutron porosity, bulk density, and the sonic transient time logs. Such well logs have never been analyzed by the methods that we utilize in the present study. The results indicate that the well logs exhibit multifractal characteristics, and the estimated Hurst exponents by the three methods are close to each other. Using multifractal detrended fluctuation analysis and the shuffled and surrogated data, we... 

    Wettability alteration in carbonates during "Smart Waterflood": Underling mechanisms and the effect of individual ions

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 487 , 2015 , Pages 142-153 ; 09277757 (ISSN) Rashid, S ; Mousapour, M. S ; Ayatollahi, S ; Vossoughi, M ; Beigy, A. H ; Sharif University of Technology
    Elsevier  2015
    Abstract
    There are increasing evidences that adjusting the chemistry of the injecting water improves the oil recovery efficiency. However, the underlying mechanisms for this technique which is referred to as "smart waterflood" have not yet been thoroughly understood. It is needed to explore the role of individual ions through set of different tests, to find the right mechanisms behind "smart waterflood". This study is focused on the fluid/solid (carbonate) interactions through systematic wettability measurement. Contact angle measurements accompanied by spontaneous imbibition tests were employed to determine the role of individual monovalent and divalent ions in wettability alteration process by... 

    Characterization of carbon nanotube dispersion and filler network formation in melted polyol for nanocomposite materials

    , Article Powder Technology ; Volume 276 , 2015 , Pages 222-231 ; 00325910 (ISSN) Pircheraghi, G ; Foudazi, R ; Manas Zloczower, I ; Sharif University of Technology
    Elsevier  2015
    Abstract
    Different grades of carbon nanotubes (CNTs) were dispersed in poly(tetramethylene ether glycol) (PTMEG) without any solvent in the presence of a block copolymer dispersing agent by ultrasonication at a temperature well above the melting point of the PTMEG. The state of CNT dispersion at different length scales was evaluated by using optical microscopy, UV-Vis spectroscopy, rheological measurements, differential scanning calorimetry, thermogravimetric analysis and sedimentation tests. Optical microscopy can be used to characterize the state of dispersion and CNT network formation on a micrometer scale, whereas UV-Vis provides useful information about the dispersion of individual CNTs at... 

    Bed mixing and leachate recycling strategies to overcome pressure drop buildup in the biofiltration of hydrogen sulfide

    , Article Bioresource Technology ; Volume 109 , 2012 , Pages 26-30 ; 09608524 (ISSN) Roshani, B ; Torkian, A ; Aslani, H ; Dehghanzadeh, R ; Sharif University of Technology
    2012
    Abstract
    The effects of leachate recycling and bed mixing on the removal rate of H 2S from waste gas stream were investigated. The experimental setup consisted of an epoxy-coated three-section biofilter with an ID of 8cm and effective bed height of 120cm. Bed material consisted of municipal solid waste compost and PVC bits with an overall porosity of 54% and dry bulk density of 0.456gcm -3. Leachate recycling had a positive effect of increasing elimination capacity (EC) up to 21gSm -3 bedh -1 at recycling rates of 75mld -1, but in the bed mixing period EC declined to 8g Sm -3bedh -1. Pressure drop had a range of zero to 18mm H 2Om -1 in the course of leachate recycling. Accumulation of sulfur reduced...