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    Characterization of the effect of disturbance on the hydro-mechanical behavior of a highly collapsible loessial soil

    , Article Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014 ; Vol. 1, issue , 2014 , p. 261-266 Haeri, S. M ; Khosravi, A ; Ghaizadeh, S ; Garakani, A. A ; Meehan, C. L ; Sharif University of Technology
    Highly collapsible loessial soils are characterized by an open void structure that can experience significant settlement upon loading. In the field, these partially saturated Aeolian deposits are particularly susceptible to wetting-induced collapse. Due to difficulties in preparing undisturbed specimens from highly collapsible soils, previous studies have generally performed laboratory tests on reconstituted specimens with different water contents and densities, and the effect of disturbance on the initial state of the soil was ignored. Disturbance in highly collapsible soil specimens may significantly affect the natural composition of the soil matrix, the non-homogeneous distribution of... 

    Synthesis of new modified MCM-41/PSF nanocomposite membrane for improvement of water permeation flux

    , Article Desalination and Water Treatment ; Volume 41, Issue 1-3 , 2012 , Pages 53-61 ; 19443994 (ISSN) Jomekian, A ; Shafiee, A ; Moradian, A ; Sharif University of Technology
    The preparation of MCM-41 nanoparticles was made using tetraethylorthosilicate as silica source and cetyltrimethylammonium bromide as surfactant. The X-ray diffraction, transmission electron microscopy, laser particle size analysis and N2 adsorption techniques were used for characterization of nanoparticles. The dimethyldichlorosilan (DMDCS) was applied to improve the dispersion of MCM-41 nanoparticles into the polysulfone (PSF) matrix. The investigation on the thermal stability with thermogravimetric analysis showed the enhanced stability of membranes possessing higher loading of MCM-41 nanaoparticles. The scanning electron microscopy was used to evaluate the quality of particles dispersion... 

    Prediction of CO2 equilibrium moisture content using least squares support vector machines algorithm

    , Article Petroleum and Coal ; Volume 58, Issue 1 , 2016 , Pages 27-46 ; 13377027 (ISSN) Ghiasi, M.M ; Abdi, J ; Bahadori, M ; Lee, M ; Bahadori, A ; Sharif University of Technology
    Slovnaft VURUP a.s  2016
    The burning of fossil fuels such as gasoline, coal, oil, natural gas in combustion reactions results in the production of carbon dioxide. The phase behavior of the carbon dioxide + water system is complex topic. Unlike methane, CO2 exhibits a minimum in the water content. These minima cannot be predicted by existing methods accurately. In this communication, two mathematical-based procedures have been proposed for accurate computation of CO2 water content for tempe-ratures between 273.15 and 348.15 K and the pressure range between 0.5 and 21 MPa. The first is based on least squares support vector machine (LSSVM) algorithm and the second applies multilayer perceptron (MLP) artificial neural... 

    Poly (vinyl alcohol)/nano-diamond composite films and hydrogels prepared by gamma ray

    , Article Journal of Polymer Engineering ; Volume 38, Issue 9 , 2018 , Pages 857-862 ; 03346447 (ISSN) Frounchi, M ; Dadbin, S ; Haddadi, S ; Sharif University of Technology
    De Gruyter  2018
    Poly (vinyl alcohol) and nano-diamond, PVA/ND, hydrogels were prepared and assessed as prosthetic material suitable for replacement of the nucleus pulposus. The hydrogels were prepared by gamma irradiation at various doses (15 kGy, 25 kGy, 35 kGy, 45 kGy) and at various ND concentrations ranging from 0.25 wt.% to 3 wt.%. Extent of gelation, equilibrium water content, and viscoelastic properties of swelled hydrogels at definite water contents were measured and examined as a function of ND concentration as well as gamma dose. According to viscoelastic measurements, the strength of hydrogels increased considerably over that of pure PVA at a low concentration of ND. By increasing irradiation... 

    Evaluation of SMAP/Sentinel 1 high-resolution soil moisture data to detect irrigation over agricultural domain

    , Article IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing ; Volume 14 , 2021 , Pages 10733-10747 ; 19391404 (ISSN) Jalilvand, E ; Abolafia Rosenzweig, R ; Tajrishy, M ; Das, N ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Irrigation is not well represented in land surface, hydrological, and climate models. One way to account for irrigation is by assimilating satellite soil moisture data that contains irrigation signal with land surface models. In this study, the irrigation detection ability of SMAP enhanced 9 km and SMAP-Sentinel 1 (SMAP-S1), 3 km and 1 km soil moisture products are evaluated using the first moment (mean) and the second moment (variability) of soil moisture data. The SMAP enhanced 9 km soil moisture product lacks irrigation signals in an irrigated plain south of Urmia Lake, whereas SMAP-S1 products record irrigation signal in soil moisture variability. Despite observing higher variability... 

    Experimental Study of the Effects of Compaction Water Content on Dynamic Properties of Babolsar Sand under Anisotropic Loading

    , M.Sc. Thesis Sharif University of Technology Khorami, Shahriar (Author) ; Jafarzadeh, Fardin (Supervisor)
    In many of the geotechnical engineering projects, such as construction of embankments and roads, soil is compacted with different water contents. Difference in compaction water content leads to different dynamic behaviors under cyclic loadings like earthquake and traffic. On the other hand, the magnitude and the direction of principal stresses on soil element, affect the dynamic response of the soil. The main objective of this research is to study the effects of compaction water content on dynamic properties of soil in anisotropic loading conditions. Therefore, the dynamic parameters of Babolsar sand, including shear strain amplitude, shear modulus and damping ratio under induced anisotropic... 

    Effect of water-methanol content on the structure of Nafion in the sandwich model and solvent dynamics in nano-channels; A molecular dynamics study

    , Article Molecular Physics ; Volume 109, Issue 5 , Mar , 2011 , Pages 709-724 ; 00268976 (ISSN) Abroshan, H ; Akbarzadeh, H ; Taherkhani, F ; Parsafar, G ; Sharif University of Technology
    Continuing an ongoing study, molecular dynamics (MD) simulations were performed to investigate the effects of methanol concentration on Nafion morphology, such as the size of solvent cluster, solvent location, and polymer structure via the sandwich model. Our survey shows that high methanol concentrations resulted in increment of solvent cluster size in Nafion membrane. The sulfonic acid clusters also befall much in order as subsequent layers of such ionic clusters are formed. The number of neighbouring hydronium ions around a sulfur atom is independent of methanol concentration, but the first shell of hydronium and water around sulfonic acid clusters is broader. Although methanol would... 

    Prediction of water content of sour and acid gases

    , Article Fluid Phase Equilibria ; Volume 299, Issue 2 , December , 2010 , Pages 171-179 ; 03783812 (ISSN) Zirrahi, M ; Azin, R ; Hassanzadeh, H ; Moshfeghian, M ; Sharif University of Technology
    Estimating the feasibility of acid gas geological disposal requires the knowledge of the water content of the gas phase at moderate pressures and temperatures (typically below 50MPa, below 380K) and up to 6mol NaCl. In this paper, a non-iterative model is developed to predict the water content of sour and acid gases at equilibrium with pure water and brine. This model is based on equating the chemical potential of water and using the modified Redlich-Kwong equation of state to calculate the fugacity of the gas phase. The water content of pure CH4, CO2 and H2S are represented with average absolute deviations of less than 3.36, 7.04 and 8.4%, respectively. Experimental data of the water... 

    Analytical and Experimental Study to Predict the Residual Resistance Factor on Polymer Flooding Process in Fractured Medium

    , Article Transport in Porous Media ; Volume 85, Issue 3 , 2010 , Pages 825-840 ; 01693913 (ISSN) Ahmad Ramazani, S. A ; Nourani, M ; Emadi, M. A ; Jafari Esfad, N ; Sharif University of Technology
    The major objectives of this study are to analytically and experimentally determine the residual resistance factor in the fractured medium based on the polymer solution properties and operational conditions. The parameters considered in this study are the polymer concentration, power law constitutive equation parameter, and salt concentration, sulfonation content of polymer, temperature, and molecular weight of the water soluble polymers which are used in polymer flooding for enhanced oil recovery. The results indicated that residual resistance factor in fractured medium is dependent on the coil overlap parameter and power law equation parameter of polymer. The coil overlap parameter is a... 

    A new study on binder performance and formulation modification of anti-corrosive primer based on ethyl silicate resin

    , Article Progress in Organic Coatings ; Volume 65, Issue 3 , 2009 , Pages 410-413 ; 03009440 (ISSN) Hoshyargar, F ; Sherafati, S. A ; Hashemi, M. M ; Sharif University of Technology
    Zinc-rich ethyl silicate coatings are quite successful in protecting steel against corrosion under severe exposing conditions. In spite of providing excellent cathodic protection to steel structure after film curing, two-component zinc-rich ethyl silicate coatings have some limitations, one of which is inadequate shelf life as a result of in-can binder gelation. In this work, the preparation steps of ethyl silicate such as pre-hydrolysis, dehydration and organometallic reactions were surveyed and herein an approach towards understanding the cause and effect relationship of the use of ingredients is presented. The effects of water and catalytic acid dosages on gel time under accelerated... 

    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
    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... 

    Experimental and theoretical study of crude oil pretreatment using low-frequency ultrasonic waves

    , Article Ultrasonics Sonochemistry ; Volume 48 , 2018 , Pages 383-395 ; 13504177 (ISSN) Khajehesamedini, A ; Sadatshojaie, A ; Parvasi, P ; Rahimpour, M. R ; Naserimojarad, M. M ; Sharif University of Technology
    In this work, an ultrasound experimental setup was designed to investigate the feasibility of using low-frequency ultrasonic waves as a substitute to reduce the consumption of chemical demulsifiers in the pretreatment of crude oil. The experiments were planned to study the effects of irradiation time, ultrasonic field intensity and initial water content on the efficiency of separation. The results of experiments showed that by selecting a proper irradiation time and field intensity, it is possible to decrease the usage of demulsifiers by 50%. Moreover, a population balance model was proposed to explicate the experimental data. A hybrid coalescence model was developed to determine the... 

    Persistent superhydrophilicity of sol-gel derived nanoporous silica thin films

    , Article Journal of Physics D: Applied Physics ; Volume 42, Issue 2 , 2009 ; 00223727 (ISSN) Ganjoo, S ; Azimirad, R ; Akhavan, O ; Moshfegh, A. Z ; Sharif University of Technology
    In this investigation, sol-gel synthesized nanoporous silica thin films, annealed at different temperatures, with long time superhydrophilic property have been studied. Two kinds of sol-gel silica thin films were fabricated by dip-coating of glass substrates in two different solutions; with low and high water. The transparent coated films were dried at 100 °C and then annealed in a temperature range of 200-500 °C. The average water contact angle of the silica films prepared with low water content and annealed at 300 °C measured about 5° for a long time (6 months) without any UV irradiation. Instead, adding water into the sol resulted in silica films with an average water contact angle... 

    Effects of solar energy on the mechanical properties of tailings in tailings dams

    , Article GeoCongress 2008: Characterization, Monitoring, and Modeling of GeoSystems, New Orleans, LA, 9 March 2008 through 12 March 2008 ; Issue 179 , 2008 , Pages 605-612 ; 08950563 (ISSN); 9780784409725 (ISBN) Osouli, A. R ; Pak, A ; Sharif University of Technology
    Mine tailings are the most common materials that are used in construction of tailings dams. Due to high level of environmental hazard and serious consequences that are associated with tailings dam failure, proper design of tailings dams is an important factor in mining industry. Water level fluctuation, change in permeability of dam foundation, seismic loads, and excessive settlements are the most common reasons of failure, particularly in upstream type tailings dams. Due to low shear strength of wet tailings, drying of tailing material is very common in practice during the dam construction. In hot climate, the received solar energy at the soil surface converts to soil heat flux, air heat... 

    Applying ultrasonic fields to separate water contained in medium-gravity crude oil emulsions and determining crude oil adhesion coefficients

    , Article Ultrasonics Sonochemistry ; Volume 70 , 2021 ; 13504177 (ISSN) Sadatshojaie, A ; Wood, D. A ; Jokar, S. M ; Rahimpour, M. R ; Sharif University of Technology
    Elsevier B.V  2021
    Separating produced water is a key part of production processing for most crude oils. It is required for quality reasons, and to avoid unnecessary transportation costs and prevent pipework corrosion rates caused by soluble salts present in the water. A complicating factor is that water is often present in crude oil in the form of emulsions. Experiments were performed to evaluate the performance of ultrasonic fields in demulsifying crude oil emulsions using novel pipe-form equipment. A horn-type piezoelectric ultrasonic transducer with a frequency of 20 kHz and power ranging from 80 W to 1000 W was used for experimental purposes. The influences of the intensity of ultrasonic fields,... 

    Nano-magnetic poly (vinyl alcohol) hydrogels

    , Article Advanced Materials Research ; Volume 829 , 2014 , Pages 539-543 ; ISSN: 10226680 ; ISBN: 9783037859070 Asadi, S ; Frounchi, M ; Dadbin, S ; Sharif University of Technology
    Surface modified magnetic nanoparticles (M-NPs) were synthetized and stabilized in poly (vinylalcohol) solution. The solutions with various magnetic nanoparticles contents were gammairradiated and magnetic poly (vinyl-alcohol) (M-PVA) hydrogels were synthesized. The magnetic hydrogels and also the un-irradiated magnetic poly (vinyl alcohol) nanocomposite films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FTIR) and mechanical measurement. The M-NPs were uniformly dispersed in the polymer matrix due to a strong interaction between the surface-modified M-NPs and polymer matrix.... 

    Disc size markedly influences concentration profiles of intravenously administered solutes in the intervertebral disc: A computational study on glucosamine as a model solute

    , Article European Spine Journal ; Vol. 23, issue. 4 , April , 2014 , p. 715-723 Motaghinasab, S ; Shirazi-Adl, A ; Parnianpour, M ; Urban, J. P. G ; Sharif University of Technology
    Purpose: Tests on animals of different species with large differences in intervertebral disc size are commonly used to investigate the therapeutic efficacy of intravenously injected solutes in the disc. We hypothesize that disc size markedly affects outcome. Methods: Here, using a small non-metabolized molecule, glucosamine (GL) as a model solute, we calculate the influence of disc size on transport of GL into rat, rabbit, dog and human discs for 10 h post intravenous-injection. We used transient finite element models and considered an identical GL supply for all animals. Results: Huge effects of disc size on GL concentration profiles were found. Post-injection GL concentration in the rat... 

    High temperature synthesis of SAPO-34: applying an L9 taguchi orthogonal design to investigate the effects of experimental parameters

    , Article Powder Technology ; Volume 217 , February , 2012 , Pages 223-230 ; 00325910 (ISSN) Dargahi, M ; Kazemian, H ; Soltanieh, M ; Hosseinpour, M ; Rohani, S ; Sharif University of Technology
    SAPO-34 zeolite-like particles were successfully synthesized at high temperature environment. An L9 orthogonal array of the Taguchi method was implemented to investigate the effects of experimental conditions to prepare SAPO-34 with respect to crystallinity of the final product phase. The results showed that the favorable phase crystallinity was improved by increasing the hydrothermal synthesis temperature and organic template content, whereas increasing the water content in synthesis mixture decreased the crystallinity. No significant changes in crystallinity of the final products were observed by increasing the synthesis duration. In addition, zeolite SAPO-5, which was formed as the... 

    Small-strain shear modulus of cement-admixed kaolinite

    , Article Geotechnical and Geological Engineering ; Volume 30, Issue 1 , Oct , 2012 , Pages 163-171 ; 09603182 (ISSN) Bahador, M ; Pak, A ; Sharif University of Technology
    An experimental study is conducted to measure small-strain shear modulus of clay-cement mixture using bender element apparatus setup in a triaxial cell. Bender element tests were conducted on cement-treated soils and the results were analyzed to study the variation of shear modulus properties of soil specimens at different cement contents, confining pressures, curing times, and compaction moisture contents. Based on the obtained results increasing the cement ratio has a significant effect on the small-strain shear modulus of the treated soils, and this effect signifies with increasing the moisture content and curing time. Rates of shear modulus enhancements due to cement content, curing... 

    A study of the water-gas shift reaction in Ru-promoted Ir-catalysed methanol carbonylation utilising experimental design methodology

    , Article Chemical Engineering Science ; Volume 66, Issue 20 , October , 2011 , Pages 4798-4806 ; 00092509 (ISSN) Hosseinpour, V ; Kazemeini, M ; Mohammadrezaee, A ; Sharif University of Technology
    The water-gas shift reaction occurs competitively to the main reaction of the Ir-catalysed methanol carbonylation process. To study the effect of seven factors including temperature, pressure, iridium, ruthenium, methyl iodide, methyl acetate and water concentrations on the formation of hydrogen and carbon dioxide as a result of the water-gas shift reaction and other side reactions in the carbonylation of methanol to acetic acid, the experimental design method combined with response surface methodology (RSM) was utilised. Central composite design at five levels (with α=1.63) was used to design experiments. A quadratic model that included the main and interaction effects of variables for H 2...