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    Experimental Investigation of Drag Reduction Induced by Superhydrophobic Surface

    , M.Sc. Thesis Sharif University of Technology Taghvaei, Ehsan (Author) ; Moosavi, Ali (Supervisor) ; Nouri Borujerdi, Ali ($item.subfieldsMap.e)
    Abstract
    The increasing demand of energy and energy consumption, urged researchers of different fields of science to investigate different aspects of energy efficiency methods. One way of optimization of energy consumption is to reduce drag force in moving objects in fluids. Changing the geometry of objects, bubble injection, air suction and blowing on surface, using nano fluid and superhydrophobic surface are just a number of drag reduction methods. Among the mentioned methods, using superhydrophobic surface due to its simplicity, low cost and no need to change in geometry of vehicles attracted attentions of researchers of all over the world. These surfaces with micro/nano roughness combined with... 

    Simulation of Water Purification with Micro and Nano Particles in Magnetic Field

    , M.Sc. Thesis Sharif University of Technology Asghari, Elmira (Author) ; Moosavi, Ali (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor)
    Abstract
    In this project, transport and absorption of magnetic particles for the purpose of water purification has been simulated. The used magnetic particles must be collected; otherwise they would cause additional pollution. Therefore, separation and absorption of particles is vital. The particles can be collected with an applied magnetic field. In this study different kinds of magnetic fields are applied and effect of different parameters, such as particle diameter, Reynolds number and magnetic field are considered. By increasing particle diameter and magnetic filed strength, the absorption efficiency increases. But by increasing Reynolds number absorption efficiency decreases. The particle with... 

    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
    Abstract
    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... 

    Design, Simulation and Fabrication of Human Pulmonary Alveolus Model on a Microchip

    , Ph.D. Dissertation Sharif University of Technology Moghadas, Hajar (Author) ; Saeedi, Mohammad Saeed (Supervisor)
    Abstract
    Microfluidic systems create great development in diseases and drug delivery in various organs of the body. In this study, human pulmonary alveolar cell performance was evaluated from the perspective of the cell culture using a microfluidic system. For this purpose, numerical simulations of the microchip channels flow field are very important to select appropriate models. So in the first step, the flow field and particle deposition were simulated. Then an optimal model was selected based on key parameters such as cell feeding, shear stress exerted on the cell, particles distribution and also the limitations and possibilities for constructing. The numerical results show that the shear stress,... 

    Stabilization of the suspension of zirconia microparticle using the nanoparticle halos mechanism: zeta potential effect

    , Article Journal of Dispersion Science and Technology ; Volume 37, Issue 1 , 2016 , Pages 6-13 ; 01932691 (ISSN) Keramati, H ; Saidi, M.H ; Zabetian, M ; Sharif University of Technology
    Taylor and Francis Inc  2016
    Abstract
    An experimental study has been conducted to investigate the effect of silica nanoparticle halos on the stability of the zirconia aqueous suspension. The results of turbidity measurements showed that addition of nanoparticles to the suspension increases the stability of the zirconia suspension for all pH values. The achieved stability refers to the formation of nanoparticle halos around the microparticles that can be observed by scanning electron microscopy (SEM) imaging. The best stabilization is achievable when zirconia microparticles are at the isoelectric point. The minimum stabilization occurs when microparticles have relatively high zeta potential and the force between micro and... 

    Spiral microchannel with stair-like cross section for size-based particle separation

    , Article Microfluidics and Nanofluidics ; Volume 21, Issue 7 , 2017 ; 16134982 (ISSN) Ghadami, S ; Kowsari Esfahan, R ; Saidi, M. S ; Firoozbakhsh, K ; Sharif University of Technology
    Springer Verlag  2017
    Abstract
    Particle separation has a variety of applications in biology, chemistry and industry. Among them, circulating tumor cells (CTCs) separation has drawn significant attention to itself due to its high impact on both cancer diagnosis and therapeutics. In recent years, there has been growing interest in using inertial microfluidics to separate micro/nano particles based on their sizes. This technique offers label-free, high-throughput and efficient separation and can be easily fabricated. However, further improvements are needed for potential clinical applications. In this study, a novel inertial separation technique using spiral microchannel having stair-like cross section is introduced. The... 

    Effects of cone angle and length of nanopores on the resistive pulse quality

    , Article Physical Chemistry Chemical Physics ; Volume 22, Issue 43 , 2020 , Pages 25306-25314 Bakouei, M ; Abdorahimzadeh, S ; Taghipoor, M ; Sharif University of Technology
    Royal Society of Chemistry  2020
    Abstract
    Resistive pulse sensing (RPS) has proved to be a viable method for the detection and characterization of micro and nano particles. Modern fabrication methods have introduced different nanopore geometries for resistive pulse sensors. In this paper, we have numerically studied the effects of membrane thickness and the pore's cone angle, as the main geometrical parameters, on the sensing performance of the nanopores used for nanoparticle detection in the resistive pulse sensing method. To compare the sensing performance, three resistive pulse quality parameters were investigated-sensitivity, pulse duration and pulse amplitude. The thorough investigation on the relations between the geometrical... 

    Performance improvement of MgO-CaO refractories by the addition of nano-sized Al2O3

    , Article Materials Chemistry and Physics ; Volume 198 , 2017 , Pages 354-359 ; 02540584 (ISSN) Shahraki, A ; Ghasemi kahrizsangi, S ; Nemati, A ; Sharif University of Technology
    Abstract
    Magnesia-dolomite refractories have advantages such as stability in the basic environments, clean steel production, high corrosion resistance, proper covering in the cement furnace, and low production costs. However, their application is restricted due to low hydration resistance. In this research, the effects of nano and micro alumina particles on the microstructure, sintering behavior, and properties of magnesia-dolomite refractories were studied. For this purpose, MgO-CaO refractories were formulated using dolomite and magnetite and 0, 2, 4, 6 and 8 wt percentage nano and micro alumina were added to the formulation. Phase and microstructure analysis of the samples were performed using... 

    Margination and adhesion of micro- and nanoparticles in the coronary circulation: a step towards optimised drug carrier design

    , Article Biomechanics and Modeling in Mechanobiology ; 2017 , Pages 1-17 ; 16177959 (ISSN) Forouzandehmehr, M ; Shamloo, A ; Sharif University of Technology
    Abstract
    Obstruction of left anterior descending artery (LAD) due to the thrombosis or atherosclerotic plaques is the leading cause of death worldwide. Targeted delivery of drugs through micro- and nanoparticles is a very promising approach for developing new strategies in clot-busting or treating restenosis. In this work, we modelled the blood flow characteristics in a patient-specific reconstructed LAD artery by the fluid–solid interaction method and based on physiological boundary conditions. Next, we provided a Lagrangian description of micro- and nanoparticles dynamics in the blood flow considering their Brownian motion and the particle–particle interactions. Our results state that the number of... 

    Solution synthesis of CuSbS2 nanocrystals: a new approach to control shape and size

    , Article Journal of Alloys and Compounds ; Volume 736 , 2018 , Pages 190-201 ; 09258388 (ISSN) Moosakhani, S ; Sabbagh Alvani, A. A ; Mohammadpour, R ; Ge, Y ; Hannula, S. P ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    Chalcostibite copper antimony sulfide (CuSbS2) micro- and nanoparticles with a different shape and size have been prepared by a new approach to hot injection route. In this method, sulfur in oleylamine (OLA) is employed as a sulfonating agent providing a simple route to control the shape and size of the particles, which enables the optimization of CuSbS2 for a variety of applications. The sulfur to metallic precursor ratio appears to be one of the most effective parameters along with the temperature and time for controlling the size and morphology of the particles. The growth mechanism study shows in addition to the CuSbS2 phase the presence of not previously observed intermediate phases... 

    The effect of micro and nano particle sizes of H-ZSM-5 on the selectivity of MTP reaction

    , Article Catalysis Communications ; Volume 10, Issue 12 , 2009 , Pages 1582-1585 ; 15667367 (ISSN) Firoozi, M ; Baghalha, M ; Asadi, M ; Sharif University of Technology
    2009
    Abstract
    The effect of particle size on the catalytic activity of H-ZSM-5 zeolite in the methanol to propylene (MTP) reaction was investigated in a fixed-bed flow reactor under the operating conditions of T = 460 °C, P = 1 atm, and WHSV = 1 h-1. Nano and micro size H-ZSM-5 were prepared by reflux and hydrothermal crystallization methods, respectively. The nano and micro H-ZSM-5 were characterized using XRD, NH3-TPD, BET area, SEM and ICP-AES analytical techniques. Nano size H-ZSM-5 showed higher activity and stability compared to the micro size H-ZSM-5. Nano H-ZSM-5 was also found to have higher selectivity to propylene than the micro size H-ZSM-5. © 2009 Elsevier B.V. All rights reserved  

    Curcumin-Loaded Starch Micro/Nano particles for biomedical application: the effects of preparation parameters on release profile

    , Article Starch/Staerke ; Volume 71, Issue 5-6 , 2019 ; 00389056 (ISSN) Dehghan Baniani, D ; Zahedifar, P ; Bagheri, R ; Solouk, A ; Sharif University of Technology
    Wiley-VCH Verlag  2019
    Abstract
    Although curcumin is highly cytotoxic against cancer cells, its hydrophobicity and fast degradation at physiological pH limit its effective practical application. To prevent such limitations, inexpensive curcumin-loaded starch particles are synthesized in this research. Particles are prepared by water-in-oil (W/O) miniemulsion technique and an adsorption method is used for curcumin loading. Also, encapsulation efficiency (%EE) is improved by using pluronic F-127 in the drug solution. Particles are characterized, swelling studies are performed, and MTT assays against human adipose mesenchymal stem cells (hAMSCs) and MG-63 cells are utilized for investigations. Results indicate that... 

    Effect of collision on self-assembly of nanoparticles in zirconia microparticle suspension

    , Article Journal of Dispersion Science and Technology ; 2020 Jiryaei, Z ; Saidi, M. H ; Sharif University of Technology
    Bellwether Publishing, Ltd  2020
    Abstract
    Nanoparticle halo mechanism is a stabilization method for microparticle suspensions. This study investigates suspension pH and nanoparticles–microparticles collision effects on the stabilization of an aqueous binary suspension. The long-term turbidity measurements show that for the nanosilica suspension stability is directly correlated with pH values; however, in the cases of zirconia and binary suspensions, it is not a monotonic function of pH. It is shown that for binary suspension, the halo mechanism is the primary method affecting the stability of the suspension. The suspension is best-stabilized at pH = 5 that is associated with high halo mechanism efficiency, while increased repulsive... 

    Effect of collision on self-assembly of nanoparticles in zirconia microparticle suspension

    , Article Journal of Dispersion Science and Technology ; Volume 43, Issue 6 , 2022 , Pages 787-795 ; 01932691 (ISSN) Jiryaei, Z ; Saidi, M. H ; Sharif University of Technology
    Taylor and Francis Ltd  2022
    Abstract
    Nanoparticle halo mechanism is a stabilization method for microparticle suspensions. This study investigates suspension pH and nanoparticles–microparticles collision effects on the stabilization of an aqueous binary suspension. The long-term turbidity measurements show that for the nanosilica suspension stability is directly correlated with pH values; however, in the cases of zirconia and binary suspensions, it is not a monotonic function of pH. It is shown that for binary suspension, the halo mechanism is the primary method affecting the stability of the suspension. The suspension is best-stabilized at pH = 5 that is associated with high halo mechanism efficiency, while increased repulsive... 

    Effect of material and population on the delivery of nanoparticles to an atherosclerotic plaque: a patient-specific in silico study

    , Article Langmuir ; Volume 37, Issue 4 , 2021 , Pages 1551-1562 ; 07437463 (ISSN) Amani, A ; Shamloo, A ; Barzegar, S ; Forouzandehmehr, M ; Sharif University of Technology
    American Chemical Society  2021
    Abstract
    Coronary artery disease (CAD) is the prevalent reason of mortality all around the world. Targeting CAD, specifically atherosclerosis, with controlled delivery of micro and nanoparticles, as drug carriers, is a very proficient approach. In this work, a patient-specific and realistic model of an atherosclerotic plaque in the left anterior descending (LAD) artery was created by image-processing of CT-scan images and implementing a finite-element mesh. Next, a fluid-solid interaction simulation considering the physiological boundary conditions was conducted. By considering the simulated force fields and particle-particle interactions, the correlation between injected particles at each cardiac... 

    Personalised deposition maps for micro- and nanoparticles targeting an atherosclerotic plaque: attributions to the receptor-mediated adsorption on the inflamed endothelial cells

    , Article Biomechanics and Modeling in Mechanobiology ; Volume 18, Issue 3 , 2019 , Pages 813-828 ; 16177959 (ISSN) Shamloo, A ; Forouzandehmehr, M ; Sharif University of Technology
    Springer Verlag  2019
    Abstract
    Endothelial inflammation as a prominent precursor to atherosclerosis elicits a distinct pathological surface expression of particular vascular proteins. To exhibit a site-specific behaviour, micro- and nanoparticles, as carriers of therapeutics or imaging agents, can distinguish and use these proteins as targeted docking sites. Here, a computational patient-specific model capturing the exclusive luminal qualities has been developed to study the transport and adsorption of particles decorated with proper antibodies over an atherosclerotic plaque located in the LAD artery of the patient. Particles, in nano- and micron sizes, have been decorated with Sialyl Lewisx (sLex), P-selectin aptamer... 

    Margination and adhesion of micro- and nanoparticles in the coronary circulation: A step towards optimised drug carrier design

    , Article Biomechanics and Modeling in Mechanobiology ; Volume 17, Issue 1 , 2018 , Pages 205-221 ; 16177959 (ISSN) Forouzandehmehr, M ; Shamloo, A ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    Obstruction of left anterior descending artery (LAD) due to the thrombosis or atherosclerotic plaques is the leading cause of death worldwide. Targeted delivery of drugs through micro- and nanoparticles is a very promising approach for developing new strategies in clot-busting or treating restenosis. In this work, we modelled the blood flow characteristics in a patient-specific reconstructed LAD artery by the fluid–solid interaction method and based on physiological boundary conditions. Next, we provided a Lagrangian description of micro- and nanoparticles dynamics in the blood flow considering their Brownian motion and the particle–particle interactions. Our results state that the number of...