Search for: magnetic-fluids
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    Modeling of self-controlling hyperthermia based on nickel alloy ferrofluids: Proposition of new nanoparticles

    , Article Journal of Magnetism and Magnetic Materials ; Volume 335 , 2013 , Pages 59-63 ; 03048853 (ISSN) Delavari H. H ; Madaah Hosseini, H. R ; Wolff, M ; Sharif University of Technology
    In order to provide sufficient heat without overheating healthy tissue in magnetic fluid hyperthermia (MFH), a careful design of the magnetic properties of nanoparticles is essential. We perform a systematic calculation of magnetic properties of Ni-alloy nanoparticles. Stoner-Wohlfarth model based theories (SWMBTs) are considered and the linear response theory (LRT) is used to extract the hysteresis loop of nickel alloy nanoparticles in alternating magnetic fields. It is demonstrated that in the safe range of magnetic field intensity and frequency the LRT cannot be used for the calculation of the area in the hysteresis for magnetic fields relevant for hyperthermia. The best composition and... 

    Hyperthermia response of PEGylated magnetic graphene nanocomposites for heating applications and accelerate antibacterial activity using magnetic fluid hyperthermia

    , Article Applied Physics A: Materials Science and Processing ; Volume 126, Issue 4 , 2020 Hatamie, S ; Shih, P. J ; Soufi Zomorod, M ; Heravi, P ; Ahadian, M. M ; Hatami, N ; Sharif University of Technology
    Springer  2020
    In this research work, graphene/cobalt nanocomposites are functionalized with polyethylene glycol (PEG) to be a platform for theranostics application and antibacterial activity. The non-covalent functionalization of PEG on the surfaces of nanocomposites improved their stability and diminished their cytotoxicity. The PEGylated nanocomposites are demonstrated to allow simultaneous administration of two cancer therapy methods such as magnetic fluids hyperthermia (MFH) which is carried out by converting magnetic energy into heat through ferromagnetic cobalt nanoparticles and heat generation through near-infrared optical absorption by the reduced graphene oxide. A concise simulation is carried... 

    An investigation on the optimum conditions of synthesizing a magnetite based ferrofluid as MRI contrast agent using Taguchi method

    , Article Materials Science- Poland ; Volume 31, Issue 2 , 2013 , Pages 253-258 ; 01371339 (ISSN) Ahmadi, R ; Hosseini, H. R. M ; Sharif University of Technology
    In this study, some stabilized magnetite based ferrofluids were synthesized using Dextran as a stabilizing agent. In order to achieve optimum experimental conditions for synthesizing ferrofluids as MRI contrast agents, the Taguchi method was used. This approach was employed to design and minimize the number of required experiments. By using the Taguchi orthogonal (L16) array, four parameters including solution temperature and alkalinity, reaction temperature and stirring rate were selected at four predetermined levels for 16 experiments. Synthesizing processes established based on this set of experimental conditions were carried out and the obtained ferrofluids were characterized using PCS,... 

    Numerical simulation of magnetic convection ferrofluid flow in a permanent magnet–inserted cavity

    , Article Journal of Magnetism and Magnetic Materials ; Volume 442 , 2017 , Pages 270-278 ; 03048853 (ISSN) Ashouri, M ; Behshad Shafii, M ; Sharif University of Technology
    The magnetic convection heat transfer in an obstructed two-dimensional square cavity is investigated numerically. The walls of the cavity are heated with different constant temperatures at two sides, and isolated at two other sides. The cavity is filled with a high Prandtl number ferrofluid. The convective force is induced by a magnetic field gradient of a thermally insulated square permanent magnet located at the center of the cavity. The results are presented in the forms of streamlines, isotherms, and Nusselt number for various values of magnetic Rayleigh numbers and permanent magnet size. Two major circulations are generated in the cavity, clockwise flow in the upper half and... 

    Visualization and comparative investigations of pulsating ferro-fluid heat pipe

    , Article Applied Thermal Engineering ; Volume 116 , 2017 , Pages 56-65 ; 13594311 (ISSN) Gandomkar, A ; Saidi, M. H ; Shafii, M. B ; Vandadi, M ; Kalan, K ; Sharif University of Technology
    Elsevier Ltd  2017
    Pulsating heat pipes (PHPs) are among the best solutions for the electronics cooling due to their low cost, effectiveness and being passive. Experiments to study the effective factors on heat transfer performance have been designed and as a result, improvement of ferrofluid PHP performance has been achieved. Two different heat pipes made of copper and glass were prepared to investigate the behavior of magnetic nanofluids. In order to find the best condition for heat transfer performance, different concentrations of nanofluid with a filling ratio of 50% were tested in 3 different cases of magnetic field. The results indicated that the ferrofluid is more stable in the glass PHP. It also shows... 

    Ferrofluid droplet formation from a nozzle using alternating magnetic field with different magnetic coil positions

    , Article Journal of Magnetism and Magnetic Materials ; Volume 498 , 2020 Favakeh, A ; Bijarchi, M. A ; Shafii, M. B ; Sharif University of Technology
    Elsevier B.V  2020
    Ferrofluid has been used in many fields, such as microfluidics, droplet formation, and heat transfer, due to its potential to be attracted in the presence of a magnetic field. Droplet formation, itself, has many applications such as emulsions, 3D micro-printers, MEMS, and electro-sprays. In this study, the mechanism of ferrofluid droplet formation from the nozzle in the presence of an alternating magnetic field was investigated. The magnetic coil was fixed at different angles with respect to gravity and the effect of the alternating magnetic field and the angle of the magnetic coil axis with respect to gravity on the produced droplet volume, satellite droplet, and droplet formation frequency... 

    Heat transfer enhancement of ferrofluid flow within a wavy channel by applying a non-uniform magnetic field

    , Article Journal of Thermal Analysis and Calorimetry ; Volume 139, Issue 5 , 2020 , Pages 3331-3343 Mousavi, S. M ; Biglarian, M ; Rabienataj Darzi, A. A ; Farhadi, M ; Hassanzadeh Afrouzi, H ; Toghraie, D ; Sharif University of Technology
    Springer Netherlands  2020
    This paper presents the effects of a non-uniform magnetic field on the hydrodynamic and thermal behavior of ferrofluid flow in a wavy channel by 3D numerical simulation. The wavy surfaces at the top and bottom of the channel are heated by constant heat fluxes. Moreover, the sidewalls are adiabatic. In the wavy section, in the perpendicular direction of the main flow, the magnetic field that linearly varies along the direction of the main flow is applied. The mathematical model that is consistent with the principles of ferrohydrodynamics and magnetohydrodynamics is used for the problem formulation. The results indicate that the wavy wall enhances the heat transfer rate on the bottom of the... 

    Numerical investigation on the effect of external varying magnetic field on the mixing of ferrofluid with deionized water inside a microchannel for lab-on-chip systems

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 Saadat, M ; Ghassemi, M ; Shafii, M. B ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Energy-efficient mixing is vital for chemical and fuel processes. To this end, a flow-focusing configuration is proposed to investigate the effect of a uniform magnetic field on the mixing of a water-based ferrofluid with two streams of deionized water. An external and varying magnetic field is imposed on a straight microchannel, and the mixing between the ferrofluid and deionized waters is qualitatively and quantitatively measured. A commercial code based on the finite-element method is used, and the simulations are validated by two experimental studies in the literature. For a magnetic flux density of 10 mT, a signal frequency of 1 Hz, a duty cycle of 0.3, an inlet velocity of 500 µm/s,... 

    The effect of non-uniform magnetic field on the efficiency of mixing in droplet-based microfluidics: a numerical investigation

    , Article Micromachines ; Volume 13, Issue 10 , 2022 ; 2072666X (ISSN) Rezaeian, M ; Nouri, M ; Hassani Gangaraj, M ; Shamloo, A ; Nasiri, R ; Sharif University of Technology
    MDPI  2022
    Achieving high efficiency and throughput in droplet-based mixing over a small characteristic length, such as microfluidic channels, is one of the crucial parameters in Lab-on-a-Chip (LOC) applications. One solution to achieve efficient mixing is to use active mixers in which an external power source is utilized to mix two fluids. One of these active methods is magnetic micromixers using ferrofluid. In this technique, magnetic nanoparticles are used to make one phase responsive to magnetic force, and then by applying a magnetic field, two fluid phases, one of which is magneto-responsive, will sufficiently mix. In this study, we investigated the effect of the magnetic field’s characteristics... 

    Heat transfer of PEGylated cobalt ferrite nanofluids for magnetic fluid hyperthermia therapy: In vitro cellular study

    , Article Journal of Magnetism and Magnetic Materials ; Volume 462 , 2018 , Pages 185-194 ; 03048853 (ISSN) Hatamie, S ; Parseh, B ; Ahadian, M. M ; Naghdabadi, F ; Saber, R ; Soleimani, M ; Sharif University of Technology
    Elsevier B.V  2018
    Hyperthermia generally means as increasing the temperature of particular region of body to rise 5 °C above the body's physiological temperature. Here, we investigate the thermal therapy of PEGylated cobalt ferrite nanoparticles prepared by hydrothermal approach on cancerous cell line in the alternative current magnetic field. To characterize of the magnetic nanoparticles (MNPs), scanning electron microscopy, dynamic light scattering, X-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometer were used. X-ray diffraction analysis confirmed the spinel phase formation of the MNPs. Cytotoxicity of MNPs using MTT assay on L929 cell lines showed the PEGylated... 

    Experimental investigation on laminar forced convection heat transfer of ferrofluids under an alternating magnetic field

    , Article Experimental Thermal and Fluid Science ; Volume 49 , 2013 , Pages 193-200 ; 08941777 (ISSN) Ghofrani, A ; Dibaei, M. H ; Hakim Sima, A ; Shafii, M. B ; Sharif University of Technology
    This research study presents an experimental investigation on forced convection heat transfer of an aqueous ferrofluid flow passing through a circular copper tube in the presence of an alternating magnetic field. The flow passes through the tube under a uniform heat flux and laminar flow conditions. The primary objective was to intensify the particle migration and disturbance of the boundary layer by utilizing the magnetic field effect on the nanoparticles for more heat transfer enhancement. Complicated convection regimes caused by interactions between magnetic nanoparticles under various conditions were studied. The process of heat transfer was examined with different volume concentrations... 

    Experimental investigation of an open loop pulsating heat pipe using ferrofluid

    , Article ASME 2012 3rd International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2012 ; 2012 , Pages 175-184 ; 9780791854778 (ISBN) Mohammadi, M ; Taslimifar, M ; Saidi, M. H ; Shafii, M. B ; Afshin, H ; Saimak, K. H ; Sharif University of Technology
    The present work investigates the thermal performance of a five turn Open Loop Pulsating Heat Pipe (OLPHP). The effects of working fluid namely water and ferrofluid, heat input, ferrofluid concentration, charging ratio, and orientation will be considered. Experimental results show that using ferrofluids can enhance the thermal performance in comparison with the case of distilled water. In addition, applying a magnetic field on the OLPHP charged with ferrofluid reduces its thermal resistance. Variation of the ferrofluid concentration results in different thermal performance of the OLPHP. Best charging ratio for the distilled water and ferrofluid without magnetic field is 60 % in most of the... 

    Effects of surface coating of nanoparticles on thermal performance of Open Loop Pulsating Heat Pipes

    , Article ASME 2012 Heat Transfer Summer Conf. Collocated with the ASME 2012 Fluids Engineering Div. Summer Meeting and the ASME 2012 10th Int. Conf. on Nanochannels, Microchannels and Minichannels, HT 2012, 8 July 2012 through 12 July 2012 ; Volume 2 , 2012 , Pages 593-599 ; 9780791844786 (ISBN) Mehdi, T ; Maziar, M ; Ali, A ; Hossein, A ; Mohammad Hassan, S ; Mohammad Behshad, S ; Siamak, K. H ; Sharif University of Technology
    Homogenous dispersing of nanoparticles in a base fluid is an excellent way to increase the thermal performance of heat transfer devices especially Heat Pipes (HPs). As a wickless, cheap and efficient heat pipe, Pulsating Heat Pipes (PHPs) are important candidates for thermal application considerations. In the present research an Open Loop Pulsating Heat Pipe (OLPHP) is fabricated and tested experimentally. The effects of working fluid namely, water, Silica Coated ferrofluid (SC ferrofluid), and ferrofluid without surface coating of nanoparticles (ferrofluid), charging ratio, heat input, and application of magnetic field on the overall thermal performance of the OLPHPs are investigated.... 

    Ultrasonic-assisted synthesis of magnetite based MRI contrast agent using cysteine as the biocapping coating

    , Article Materials Chemistry and Physics ; Volume 131, Issue 1-2 , 2011 , Pages 170-177 ; 02540584 (ISSN) Ahmadi, R ; Malek, M ; Hosseini, H. R. M ; Shokrgozar, M. A ; Oghabian, M. A ; Masoudi, A ; Gu, N ; Zhang, Y ; Sharif University of Technology
    Magnetite nanoparticles (mean particle size ranging from 10 to 20 nm) were prepared by a biomoleculeassisted solution-phase approach under ultrasonic irradiation. Cysteine was used as the capping agent in the solution. The results show that cysteine could be an efficient biocapping agent in producing Fe3O4 nanoparticles. The crystal structure and magnetic properties of the nanoparticles were characterized by XRD and VSM techniques, respectively. FT-IR was used to investigate the presence of cysteine on the nanoparticles surface. The influence of pH value of the solution on the size distribution and hydrodynamic size of nanoparticles were studied by TEM and DLS methods, respectively. The MTT... 

    Experimental investigation into laminar forced convective heat transfer of ferrofluids under constant and oscillating magnetic field with different magnetic field arrangements and oscillation modes

    , Article Experimental Thermal and Fluid Science ; Volume 68 , November , 2015 , Pages 601-611 ; 08941777 (ISSN) Yarahmadi, M ; Moazami Goudarzi, H ; Shafii, M. B ; Sharif University of Technology
    Elsevier Inc  2015
    In this study, the effects of ferrofluids on the forced convective heat transfer in a tube with a round cross section under constant heat flux in the laminar flow regime are investigated experimentally. For this purpose, an experimental setup was designed and built. Furthermore, the effects of an external magnetic field on the forced convective heat transfer were examined for various Reynolds numbers and volume concentrations. The parameters of magnetic field strength, magnetic field arrangement, the constancy or oscillation of the magnetic field and also its oscillatory mode were examined. As a result of the experimental studies, in the absence of a magnetic field enhancement in convective... 

    Thermal Conductivity of Fe2O3 and Fe3O4 Magnetic Nanofluids Under the Influence of Magnetic Field

    , Article International Journal of Thermophysics ; Volume 36, Issue 10-11 , September , 2015 , Pages 2720-2739 ; 0195928X (ISSN) Karimi, A ; Goharkhah, M ; Ashjaee, M ; Shafii, M. B ; Sharif University of Technology
    Springer New York LLC  2015
    In this paper, the thermal conductivity of water-based hematite Fe2O3 and magnetite Fe3O4 nanofluids have been investigated in the absence and presence of a uniform magnetic field. The experiments have been performed in the volume concentration range of 0 % to 4.8 % and the temperature range of 20∘C to 60∘C. The effects of the particle volume fraction, temperature, and magnetic field strength on the thermal conductivity have been analyzed. Results show that the thermal conductivity of iron oxide nanofluids has a direct relation with the particle volume fraction and temperature, without the presence of a magnetic field. But surprisingly, when the magnetic field is applied, it is observed that... 

    Effect of magnetic field on thermal conductivity and viscosity of a magnetic nanofluid loaded with carbon nanotubes

    , Article Journal of Mechanical Science and Technology ; Volume 30, Issue 2 , 2016 , Pages 809-815 ; 1738494X (ISSN) Shahsavar, A ; Salim Pour, M. R ; Saghafian, M ; Shafii, M. B ; Sharif University of Technology
    Korean Society of Mechanical Engineers 
    The present work examines experimentally the effect of magnetic field on the viscosity and thermal conductivity of a hybrid nanofluid containing tetramethylammonium hydroxide (TMAH) coated Fe3O4 nanoparticles and Gum arabic (GA) coated carbon nanotubes (CNTs). The hybrid nanofluid was prepared by using ultrasonic dispersion method. Magnetic field was created by a pair of spaced apart magnet plates. The effect of temperature on the time variation of thermal conductivity under applied magnetic field was also investigated. According to the results of this study, viscosity of the hybrid nanofluid increases with the strength of magnetic field, while it decreases with the increase of temperature.... 

    Experimental study on heat transfer augmentation of graphene based ferrofluids in presence of magnetic field

    , Article Applied Thermal Engineering ; Volume 114 , 2017 , Pages 415-427 ; 13594311 (ISSN) Sadeghinezhad, E ; Mehrali, M ; Akhiani, A. R ; Tahan Latibari, S ; Dolatshahi Pirouz, A ; Metselaar, H. S. C ; Mehrali, M ; Sharif University of Technology
    Elsevier Ltd  2017
    The effect of a permanent magnetic field on the heat transfer characteristics of hybrid graphene-magnetite nanofluids (hybrid nanofluid) under forced laminar flow was experimentally investigated. For this purpose, a reduced graphene oxide-Fe3O4 was synthesized by using two-dimensional (2D) graphene oxide, iron salts and tannic acid as the reductant and stabilizer. Graphene sheets acted as the supporting materials to enhance the stability and thermal properties of magnetite nanoparticles. The thermo-physical and magnetic properties of this hybrid nanofluid have been widely characterized and it shows that the thermal conductivity increased up to 11%. The hybrid nanofluid behaves as a Newtonian... 

    Reactive absorption in packed bed columns in the presence of magnetic nanoparticles and magnetic field: Modeling and simulation

    , Article Journal of Industrial and Engineering Chemistry ; Volume 45 , 2017 , Pages 131-144 ; 1226086X (ISSN) Rahimi, M ; Molaei Dehkordi, A ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2017
    In this article, the influences of ferrofluid and magnetic field on the reactive absorption in packed-bed contactors have been investigated. Because of importance of carbon dioxide emission as a global concern, absorption of carbon dioxide was chosen to investigate these effects. In this regard, multitube approach was applied to model the contactor. The simulation results were validated against experimental data reported in the literature in the absence of nanoparticles and magnetic field and good agreement was obtained. Moreover, influences of various operating conditions on the contactor performance were investigated. It was found that for 3.4 vol.% of magnetic nanoparticles (MNPs), the... 

    Theoretical and experimental studies of a magnetically actuated valveless micropump

    , Article Journal of Micromechanics and Microengineering ; Volume 27, Issue 1 , 2017 ; 09601317 (ISSN) Ashouri, M ; Shafii, M. B ; Moosavi, A ; Sharif University of Technology
    Institute of Physics Publishing  2017
    This paper presents the prototype design, fabrication, and characterization of a magnetically actuated micropump. The pump body consists of three nozzle/diffuser elements and two pumping chambers connected to the ends of a flat-wall pumping cylinder. A cylindrical permanent magnet placed inside the pumping cylinder acts as a piston which reciprocates by using an external magnetic actuator driven by a motor. The magnetic piston is covered by a ferrofluid to provide self-sealing capability. A prototype composed of three bonded layers of polymethyl-methacrylate (PMMA) has been fabricated. Water has been successfully pumped at pressures of up to 750 Pa and flow rates of up to 700 μl min-1 while...