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    Evaluation of viscosity and thermal conductivity of graphene nanoplatelets nanofluids through a combined experimental–statistical approach using respond surface methodology method

    , Article International Communications in Heat and Mass Transfer ; Volume 79 , 2016 , Pages 74-80 ; 07351933 (ISSN) Iranmanesh, S ; Mehrali, M ; Sadeghinezhad, E ; Ang, B. C ; Ong, H. C ; Esmaeilzadeh, A ; Sharif University of Technology
    Elsevier Ltd 
    In the present study, three influential parameters including concentration, temperature and specific surface area of graphene nanosheets were investigated, which are the effective parameters on the viscosity and thermal conductivity of aqueous graphene nanosheets (GNP) nanofluids. A mathematical model developed by respond surface methodology (RSM) based on a central composite design (CCD). Also, the significance of the models was tested using the analysis of variance (ANOVA). The optimum results of aqueous GNP nanofluid showed that the concentration has a direct effect on the relative viscosity and thermal conductivity. Furthermore, predicted responses proposed by the Design Expert software... 

    The axial and lateral behavior of low strength concrete confined by GFRP wraps: an experimental investigation

    , Article Structures ; Volume 27 , October , 2020 , Pages 747-766 Khaloo, A ; Tabatabaeian, M ; Khaloo, H ; Sharif University of Technology
    Elsevier Ltd  2020
    The purpose of this investigation is to investigate the axial and lateral behavior of low strength concrete confined by glass fiber reinforced polymer (GFRP) wraps. A total of 48 cylindrical samples having 150 mm diameter and 300 mm height were strengthened and examined. The mix designs were provided with four different target strength (5, 10, 15, and 20 MPa). The axial and lateral strain were studied to evaluate the axial strain relation and the lateral strain for axial compression. The results of this investigation present a comparison between the nine models previously reported for normal strength concrete and the lesser-known context of low strength concrete confined by fiber reinforced... 

    The large scale maximal covering location problem

    , Article Scientia Iranica ; Volume 18, Issue 6 , December , 2011 , Pages 1564-1570 ; 10263098 (ISSN) Fazel Zarandi, M. H ; Davari, S ; Haddad Sisakht, S. A ; Sharif University of Technology
    The maximal covering location problem (MCLP) is a challenging problem with numerous applications in practice. Previous publications in the area of MCLP proposed models and presented solution methodologies to solve this problem with up to 900 nodes. Due to the fact that in real-life applications, the number of nodes could be much higher, this paper presents a customized Genetic Algorithm (GA) to solve MCLP instances, with up to 2500 nodes. Results show that the proposed approach is capable of solving problems with a fair amount of exactness. In order to fine-tune the algorithm, Tukey's Least Significant Difference (LSD) tests are employed on a set of test problems  

    Waste ceramic powder-based geopolymer mortars: effect of curing temperature and alkaline solution-to-binder ratio

    , Article Construction and Building Materials ; Volume 227 , 2019 ; 09500618 (ISSN) Shoaei, P ; Musaeei, H. R ; Mirlohi, F ; Narimani zamanabadi, S ; Ameri, F ; Bahrami, N ; Sharif University of Technology
    Elsevier Ltd  2019
    In this study, the optimum curing temperature and alkaline solution-to-binder (S:B) ratio of geopolymer mortars based on waste ceramic powder (WCP) were investigated. For this purpose, mixes with S:B ratios of 0.4–0.7 were prepared and cured at 60, 75, 90, and 105 °C. The density, compressive and flexural strengths were measured at 3, 7, 14, and 28 days. Higher S:B ratios enhanced the flow of the fresh mortar. The optimum mortar was obtained for S:B ratio of 0.6 and curing temperature of 90 °C. The SEM analysis revealed that the optimal mix had a dense matrix with minimum pores. © 2019 Elsevier Ltd  

    Cleaner distribution of electricity energy considering Personnel's attitudes toward waste generation

    , Article Journal of Cleaner Production ; Volume 209 , 2019 , Pages 371-385 ; 09596526 (ISSN) Jamshidieini, B ; Rezaie, K ; Fotuhi Firuzabad, M ; Sharif University of Technology
    Elsevier Ltd  2019
    Electrification involves many activities that have detrimental impacts on environment. Over the last few years, many studies have been conducted to understand, estimate and mitigate the carbon footprint of electricity distribution but other environmental aspects of electrification remain almost neglected. In recent years, electricity distribution companies have adopted many waste management techniques to reduce the amount of waste generated in their key processes. However, the causes of waste and the necessary corrective actions to alleviate the waste generation in electricity distribution have not been studies in an integrated framework. In current study, which was conducted to fill this... 

    Laboratory and in situ investigation of the compressive strength of CFRD concrete

    , Article Construction and Building Materials ; Volume 242 , 2020 Vatani Oskouei, A ; Nazari, R ; Houshmand Khaneghahi, M ; Sharif University of Technology
    Elsevier Ltd  2020
    One of the most essential and costly stages in Concrete Face Rockfill Dams (CFRD) construction is to implement the concrete at the upstream face of the dam without joints. As the face concrete is considered as the most integral part to prevent water penetration in CFRDs, it's quality control is of paramount importance. One of the conventional approaches for quality control of the concrete which is used in CFRD is the compressive strength of laboratory samples. The comparison of laboratory and in situ measurements provides information about the accuracy of the obtained results. This research investigates the correlation of concrete compressive strength determined by using different methods in... 

    Experimental investigation of operating conditions for preparation of PVA-PEG blend membranes using supercritical CO2

    , Article Journal of Supercritical Fluids ; Vol. 95 , November , 2014 , pp. 603-609 ; ISSN: 08968446 Taji, S ; Nejad-Sadeghi, M ; Goodarznia, I ; Sharif University of Technology
    Poly(vinyl alcohol)-polyethylene glycol, PVA-PEG, blended membrane were prepared using supercritical fluid assisted phase-inversion method, in which scCO2 was used as the anti-solvent. Poly(vinyl alcohol) was utilized as the main polymer, polyethylene glycol as the additive, and dimethyl sulfoxide (DMSO) as the solvent of these polymers. Taguchi method was used to investigate the effect of some operating parameters on the morphology of the membranes. The L16 orthogonal array was selected under the following conditions: pressure (100, 135, 165 and 200 bar), temperature (40, 45, 50 and 55°C) and PEG weight percent (0, 0.33, 0.66, and 1%). Total polymer concentration of solutions in all... 

    An investigation on the precipitation hardening of an ultrafine grained Al6063-Al2O3 nanocomposite

    , Article Proceedings of the International Euro Powder Metallurgy Congress and Exhibition, Euro PM 2012 ; Volume 1 , 2012 ; 9781899072361 (ISBN) Asgharzadeh, H ; Bayazid, M ; Simchi, A ; Sharif University of Technology
    In this work, age hardening behavior of an ultrafine-grained (UFG) Al6063-0.8 vol.% Al2O3 nanocomposite produced via reactive mechanical alloying followed by hot extrusion method by means of T6 heat treatment was studied. The temperature and time of solutionizing and aging were optimized by the Taguchi method. The optimal heat treatment condition was found to be solutionizing at 510 °C for 1.5 h and aging at 170 °C for 8 h. The signal-to-noise (S/N) ratio and analysis of variance (ANOVA) revealed that the solutionizing temperature was the most significant factor. A novel cyclic solution treatment was developed for age hardening of Al6063-Al2O3 nanocomposite. The results showed a considerable... 

    Hydrothermal synthesis of CuO nanoparticles: Study on effects of operational conditions on yield, purity, and size of the nanoparticles

    , Article Industrial and Engineering Chemistry Research ; Volume 50, Issue 6 , February , 2011 , Pages 3540-3554 ; 08885885 (ISSN) Outokesh, M ; Hosseinpour, M ; Ahmadi, S. J ; Mousavand, T ; Sadjadi, S ; Soltanian, W ; Sharif University of Technology
    Hydrothermal synthesis of CuO nanoparticles under near-critical and supercritical conditions was investigated from two different standpoints in the current study. The first standpoint was optimization of "yield", "purity", and "size of the nanoparticles" that were optimized at T = 500 °C, time = 2 h, [Cu(NO3)2] = 0.1 mol dm-3, and pH 3. This was achieved by undertaking an orthogonal experiment design methodology and performing different instrumental analyses, such as X-ray diffractometry, inductively coupled plasma spectrometry, and transmission electron microscopy, along with treatment of the data by analysis of variance (ANOVA). The second goal of the study was elucidation of the... 

    Effect of pulse current parameters on the mechanical and corrosion properties of anodized nanoporous aluminum coatings

    , Article Materials Chemistry and Physics ; Volume 183 , 2016 , Pages 490-498 ; 02540584 (ISSN) Mohammadi, I ; Ahmadi, Sh ; Afshar, A ; Sharif University of Technology
    Elsevier Ltd  2016
    In this study, the effects of pulse current parameters on corrosion resistance and mechanical properties of anodized coatings were evaluated. Hardness measurements, polarization and electrochemical impedance spectroscopy tests were employed to investigate the mechanical properties and corrosion behavior of these coatings. Also, field emission scanning electron microscopy (FE-SEM) was used to analyze the surface morphology and microstructure of the coatings. It was found that the properties of anodized coatings were dependent on various parameters, among which, time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were optimized. Analysis of Variance... 

    Preparation and characterization of a composite biomaterial including starch micro/nano particles loaded chitosan gel

    , Article Carbohydrate Polymers ; Volume 174 , 2017 , Pages 633-645 ; 01448617 (ISSN) Dehghan Baniani, D ; Bagheri, R ; Solouk, A ; Sharif University of Technology
    Thermosensitive Chitosan hydrogels which can be injected into defects with minimally invasive approach were prepared. Also starch micro/nano particles were synthesized via water-in-oil (W/O) miniemulsion technique. The starch particles were incorporated into the chitosan hydrogel to prepare injectable thermosensitive hydrogel composites. Tube inverting method, compression tests, swelling studies, XRD, SEM, OM, DLS, UV–vis spectroscopy were used for investigations. Results revealed that increasing crosslinker and surfactant contents and stirring rate leads to particle size reduction. Particle size was modeled using design of experiments (DOE) via the response surface method (RSM). Due to... 

    Effect of applied stress and bar characteristics on the short-term creep behavior of FRP bars

    , Article Construction and Building Materials ; May , Volume 171 , 2018 , Pages 960-968 ; 09500618 (ISSN) Pournamazian Najafabadi, E ; Bazli, M ; Ashrafi, H ; Vatani Oskouei, A ; Sharif University of Technology
    Elsevier Ltd  2018
    This paper presents the creep behavior of various FRP (GFRP, CFRP, and hybrid) bars in order to investigate the effects of different parameters, including the applied stress levels, bar diameter, and the type of fiber and resin in the creep behavior of FRP bars. The creep strains versus time curves were experimentally obtained for 83 days. Moreover, a statistical study, including analysis of variance (ANOVA) and linear Bayesian regression was conducted to investigate the contribution of the studied parameters. The results showed that in GFRP bars the ratio of ultimate creep strain to the initial elastic strain decreased when the applied stresses on the bars exceeded 30% of their ultimate... 

    Optimizing the mixture design of polymer concrete: An experimental investigation

    , Article Construction and Building Materials ; Volume 167 , 2018 , Pages 185-196 ; 09500618 (ISSN) Jafari, K ; Tabatabaeian, M ; Joshaghani, A ; Ozbakkaloglu, T ; Sharif University of Technology
    Elsevier Ltd  2018
    Over the last few decades, polymer concrete (PC) has been finding use in quick repairing of concrete structures. However, there have been only few studies on the mechanical behavior of PC. The aim of this study is to evaluate the mechanical behavior of PC using destructive and non-destructive tests (NDT). The mixtures were prepared with three different polymer ratios (10%, 12%, and 14%) and two different coarse aggregate sizes (4.75–9.5 mm and 9.5–19 mm). The samples were subsequently tested under three different temperatures (−15 °C, +25 °C, and +65 °C). The Taguchi method and analysis of variance (ANOVA) were used to optimize PC mixes based on the compressive, splitting-tensile, and... 

    Geopolymers vs. alkali-activated materials (AAMs): A comparative study on durability, microstructure, and resistance to elevated temperatures of lightweight mortars

    , Article Construction and Building Materials ; Volume 222 , 2019 , Pages 49-63 ; 09500618 (ISSN) Ameri, F ; Shoaei, P ; Zareei, S. A ; Behforouz, B ; Sharif University of Technology
    Elsevier Ltd  2019
    This paper studied the durability, microstructure, and fire behavior of lightweight mortars based on cement, metakaolin (MK), ultrafine ground granulated blast furnace slag (UGGBFS), ceramic waste powder (CWP), and clay brick waste powder (CBWP). Two sets of mixes were prepared with two types of lightweight aggregate including lightweight expanded clay aggregate (LECA) and pumice aggregate. Regarding the durability assessment, the electrical resistivity and water absorption of the mortars were measured. The UGGBFS-based alkali-activated mortar with pumice aggregate exhibited the highest electrical resistivity and lowest water absorption, while CBWP-based geopolymer mortar with LECA showed... 

    Surface modification of polysulfone ultrafiltration membranes by free radical graft polymerization of acrylic acid using response surface methodology

    , Article Journal of Polymer Research ; Volume 26, Issue 9 , 2019 ; 10229760 (ISSN) Ganj, M ; Asadollahi, M ; Mousavi, S. A ; Bastani, D ; Aghaeifard, F ; Sharif University of Technology
    Springer Netherlands  2019
    In this research, polysulfone (PSf) ultrafiltration (UF) membranes were prepared by a phase inversion method. Surface modification of the PSf membranes was carried out via grafting of acrylic acid as a hydrophilic monomer by free radical graft polymerization initiated by redox reaction. A central composite design (CCD) of response surface methodology (RSM) was applied to design the experiments. The process variables were acrylic acid concentration (CAA), redox system contact time (T1), and acrylic acid polymerization time (T2), while the contact angle (CA), pure water flux (PWF), and flux recovery ratio (FRR) were considered as the responses. Analysis of variance (ANOVA) demonstrated that... 

    An experimental investigation of nanoemulsion enhanced oil recovery: Use of unconsolidated porous systems

    , Article Fuel ; Volume 251 , 2019 , Pages 754-762 ; 00162361 (ISSN) Jalilian, M ; Tabzar, A ; Ghasemi, V ; Mohammadzadeh, O ; Pourafshary, P ; Rezaei, N ; Zendehboudi, S ; Sharif University of Technology
    Elsevier Ltd  2019
    Utilization of nanoparticles in oil and gas industry has attracted considerable attention of engineers and researchers. In this article, the feasibility of nanoemulsion flooding is investigated as a method for Enhanced Oil Recovery (EOR) through coreflooding experiments, using a packed bed and real reservoir fluids. Nine different mixtures of the solvent, surfactant, and nanoparticles in the form of a nanoemulsion phase are generated and used to recover the oil in the context of an EOR process. Various tests are conducted to determine the properties of porous medium and fluids. To study the production performance of this EOR technique, pressure drop across the packed bed are measured, along... 

    The tensile performance of FRP bars embedded in concrete under elevated temperatures

    , Article Construction and Building Materials ; Volume 211 , 2019 , Pages 1138-1152 ; 09500618 (ISSN) Pournamazian Najafabadi, E ; Vatani Oskouei, A ; Khaneghahi, M. H ; Shoaei, P ; Ozbakkaloglu, T ; Sharif University of Technology
    Elsevier Ltd  2019
    In this research, the mechanical properties of glass and carbon fiber reinforced polymer (FRP) bars with epoxy resin matrices embedded in concrete were investigated under an extensive range of elevated temperatures (i.e., 25–800 °C). Embedded FRP bars with various bar diameters were studied in order to determine bar diameter influence on the results. In addition, analysis of variance (ANOVA) was performed on the experimental results to investigate the contribution of exposure temperature and bar diameter to the tensile behavior of embedded in concrete FRP bars at elevated temperatures. The results show that the tensile strength of embedded FRP bars generally decreases with increasing... 

    Analyzing and predicting permeability coefficient of roller-compacted concrete (RCC)

    , Article Journal of Testing and Evaluation ; Volume 49, Issue 3 , 2019 ; 00903973 (ISSN) Heidarnezhad, F ; Toufigh, V ; Ghaemian, M ; Sharif University of Technology
    ASTM International  2019
    The permeability of roller-compacted concrete (RCC) substantially affects its functionality and safety. This study investigates the effect of mix design parameters on the performance of RCC. For this purpose, approximately 500 laboratory specimens were prepared and tested. A formula and an artificial neural network (ANN) were proposed to predict the permeability coefficient of RCC by considering the main parameters, which were then verified independently using new specimens. Furthermore, the experimental data were analyzed by the Taguchi method and analysis of variance (ANOVA) to evaluate the level of parameter contribution. Based on the results, the permeability coefficient was highly... 

    Experimental modeling and optimizing process parameters in the laser assisted machining of silicon carbide particle-reinforced aluminum matrix composites

    , Article Materials Research Express ; Volume 6, Issue 8 , 2019 ; 20531591 (ISSN) Mirshamsi, S. M. A ; Movahhedy, M. R ; Khodaygan, S ; Sharif University of Technology
    Institute of Physics Publishing  2019
    The process of laser assisted machining (LAM) of metal matrix composites (MMC) is experimentally studied. The effects of process parameters (cutting speed, feed rate and depth of cut), laser parameters (laser power, laser frequency and laser beam angle), and the percentage of reinforcing particles on the tool wear and the surface roughness are investigated. Furthermore, the effects of the mentioned parameters on the built-up edge (BUE), chip shape, and workpiece temperature are explored. The experiments were performed using uncoated tungsten carbide and PCD tools under dry conditions. In order to analyze the sensitivity of the process parameters, the Plackett-Burman method was used for... 

    Evaluation of the performance and temperature susceptibility of gilsonite- and SBS-modified asphalt binders

    , Article Construction and Building Materials ; Volume 207 , 2019 , Pages 679-692 ; 09500618 (ISSN) Mirzaiyan, D ; Ameri, M ; Amini, A ; Sabouri, M ; Norouzi, A ; Sharif University of Technology
    Elsevier Ltd  2019
    This study investigated the effect of gilsonite and Styrene-Butadiene-Styrene (SBS) as asphalt binder modifiers on the physical and rheological properties of asphalt binders. For this, binder tests such as penetration test, softening point, rotational viscosity (RV), Dynamic Shear Rheometer (DSR), and Bending Beam Rheometer (BBR) were conducted on the neat and modified binders. The effect of gilsonite and SBS on the binder temperature susceptibility was also investigated by measuring Penetration Index (PI), Activation Energy (AE) and Viscosity-Temperature Susceptibility (VTS) of all the study binders. Fourier-Transform Infrared Spectroscopy (FTIR) test was directed toward investigation of...