Search for: effective-concentration
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    Reduction of fine migration in different pH and salinity conditions using nanofluid

    , Article SPE - European Formation Damage Conference, Proceedings, EFDC ; Volume 2 , 2013 , Pages 737-743 ; 9781627486101 (ISBN) Asset, Y ; Pourafshary, P ; Ayatollahi, S ; Sharif University of Technology
    Movement and transportation of fine particles in formations leads to clogging the pores and reduction in permeability. This type of formation damage is stronglycontingent upon water salinity and ionic conditions in the formation. The main parameters which control the particle release are the interactions and forces between particles and porous medium surfaces. Changing salinity which leads to pH alteration, affects these interactions and subsequently the fine migration process. Hence, pH and salinity variations should be considered to study and evaluate the portion of fine migration in formation damage. The principal challenge in this research therefore, is to try to change the surface... 

    Influence of material and geometrical parameters on stress field of composite plates with insert

    , Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 226, Issue 12 , 2012 , Pages 1573-1582 ; 09544100 (ISSN) Mazraehshahi, H. T ; Zakeri, A. A ; Sharif University of Technology
    Reduction of stress concentrations in the area of pin-loaded holes is one of the greatest challenges in the design of multilayered fibre-reinforced composite structures. Among many approaches to decrease concentration effects, putting metallic inserts in the holes is a convenient method. In this research, finite element analysis is applied to assess the effects of manufacturing parameters on stress concentration in the vicinity of the holes in composite plates with inserts. Edge and pitch distance, thickness and materials of insert, clearance between insert and composite part, and stiffness of the adhesive filling the gap are studied in this article. Investigations show that the optimum... 

    Nontoxic concentrations of PEGylated graphene nanoribbons for selective cancer cell imaging and photothermal therapy

    , Article Journal of Materials Chemistry ; Volume 22, Issue 38 , 2012 , Pages 20626-20633 ; 09599428 (ISSN) Akhavan, O ; Ghaderi, E ; Emamy, H ; Sharif University of Technology
    Reduced graphene oxide nanoribbons functionalized by amphiphilic polyethylene glycol (rGONR-PEG) were applied to attach arginine-glycine-aspartic acid (RGD)-based peptide and cyanine dye 3 (cy3) for targeting ανβ3 integrin receptors on human glioblastoma cell line U87MG and its selective fluorescence imaging, respectively. The rGONR-PEG suspension with a concentration of 100 μg mL -1 showed ∼14 and 2.4-fold higher near infrared (NIR) absorption at 808 nm than GONR (with dimensions of ∼80 nm × 1 μm) and rGO-PEG sheets (with lateral dimensions of ∼2 μm), respectively. The rGONR-PEG-cy3-RGD exhibited highly efficient NIR photothermal therapy performance (concentrations ≥1.0 μg mL-1 resulted in... 

    Study of self-diffusion in two binary solutions, glycerol-water and methanol-water using diffusion-ordered spectroscopy

    , Article Scientia Iranica ; Volume 23, Issue 3 , 2016 , Pages 1175-1183 ; 10263098 (ISSN) Fadaei, E ; Tafazzoli, M ; Sharif University of Technology
    Sharif University of Technology 
    The concentration and temperature behaviors of the self-diffusion coefficient were analyzed in glycerol-water and methanol-water solutions using Diffusion-Ordered Spectroscopy (DOSY) experiment. Our results indicate that the self-diffusion coefficient dips with increasing concentration and decreasing temperature. The concentration behavior shows that there is hydrogen bond interaction between water and alcohol, which declines the self-diffusion coefficients of both in the aqueous binary mixtures. The self-diffusion activation energies were estimated 13.6, 29.4, and 32.8 (kJ/mol) for methanol and 24.8, 25.5, and 27.6 (kJ/mol) for water in the methanol-water solutions with 0.03, 0.10, and 0.20... 

    The effects of Fe(II) and Fe(III) concentration and initial pH on microbial leaching of low-grade sphalerite ore in a column reactor

    , Article Bioresource Technology ; Volume 99, Issue 8 , 2008 , Pages 2840-2845 ; 09608524 (ISSN) Mousavi, S. M ; Yaghmaei, S ; Vossoughi, M ; Roostaazad, R ; Jafari, A ; Ebrahimi, M ; Chabok, O. H ; Turunen, I ; Sharif University of Technology
    In this study the effects of initial concentration of Fe(II) and Fe(III) ions as well as initial pH on the bioleaching of a low-grade sphalerite ore in a leaching column over a period of 120 days with and without bacteria were investigated. Four different modifications of medium were used as column feed solutions to investigate the effects of initial concentration of Fe(II) and Fe(III) ions on zinc extraction. The experiments were carried out using a bench-scale, column leaching reactor, which was inoculated with mesophilic iron oxidizing bacteria, Acidithiobacillus ferrooxidans, initially isolated from the Sarcheshmeh chalcopyrite concentrate (Kerman, Iran). The effluent solutions were... 

    Simulation of low density lipoprotein (LDL) permeation into multilayer coronary arterial wall: interactive effects of wall shear stress and fluid-structure interaction in hypertension

    , Article Journal of Biomechanics ; Volume 67 , 2018 , Pages 114-122 ; 00219290 (ISSN) Roustaei, M ; Nikmaneshi, M. R ; Firoozabadi, B ; Sharif University of Technology
    Elsevier Ltd  2018
    Due to increased atherosclerosis-caused mortality, identification of its genesis and development is of great importance. Although, key factors of the origin of the disease is still unknown, it is widely believed that cholesterol particle penetration and accumulation in arterial wall is mainly responsible for further wall thickening and decreased rate of blood flow during a gradual progression. To date, various effective components are recognized whose simultaneous consideration would lead to a more accurate approximation of Low Density Lipoprotein (LDL) distribution within the wall. In this research, a multilayer Fluid-Structure Interaction (FSI) model is studied to simulate the penetration...