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Angular dependence of switching field of magnetic recording particles
, Article Physica B: Condensed Matter ; Volume 321, Issue 1-4 , 2002 , Pages 120-123 ; 09214526 (ISSN) ; Akhavan, M ; Sharif University of Technology
2002
Abstract
In a magnetic recording media, anisotropic particles are placed with different directions in the head field. The switching field, Hs of a particle at a certain direction is defined as the minimum field, which reverses its easy axis magnetization. To determine the position of magnetization transition in recording media, one needs the angular dependence of the switching field. To find this for a texture of anisotropic single domain particles, the acicular iron particles with 0.3 μm length have been grown in a magnetic field. Then, the textures of the particles have been oriented by another magnetic field. We have measured the remanent magnetization of samples mr(θ) and mr(H), respectively, as...
High throughput solution exchange of microparticles using magnetophoresis in curved microchannels
, Article 21st International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2017, 22 October 2017 through 26 October 2017 ; 2020 , Pages 1324-1325 ; Zareian, S ; Rezai, P ; The Chemical and Biological Microsystems Society (CBMS) ; Sharif University of Technology
Chemical and Biological Microsystems Society
2020
Abstract
A novel method involving focusing of magnetic particles at the inner wall of a curved microchannel and secondary Dean flow-based exchange of their fluid was investigated. Solution exchange occurred in a hybrid microchip at very high throughput and with unprecedented solution exchange and particle isolation efficiencies of 99.2% and 90%, respectively. © 17CBMS-0001
Simulation of Water Purification with Micro and Nano Particles in Magnetic Field
, M.Sc. Thesis Sharif University of Technology ; 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...
Study on the Efficiency of Graphene and Graphene Oxide-coated Iron Oxide Nanoparticles in the Treatment of Cancer Cells to Hyperthermia
, M.Sc. Thesis Sharif University of Technology ; Otukesh, Mohammad (Supervisor) ; Saligheh Rad, Hamid Reza (Co-Advisor)
Abstract
The main methods have been used clinically for cancer treatment are included: surgery, chemotherapy, radiation therapy and hyperthermia. Hyperthermia (heat therapy) treatment method in which by raising the temperature of the tumor it removed. Magnetic hyperthermia is known as a kind of hyperthermia that have been represent appropriate results. In this study, using iron oxide nanoparticle coated with graphene for cancer treatment under a magnetic field of the laser. In the first stage, graphene oxide nanosheets and nanoparticles Magntayt are synthesized by chemical oxidation and co-precipitation, respectively. At the end, the nanoparticles on the substrate of graphene layer is obtained...
Dynamic Modeling and Localization of a Moving Magnetic Particle in a Fluid for Capsule Endoscopy Application
, M.Sc. Thesis Sharif University of Technology ; Nejat Pishkenari, Hossein (Supervisor)
Abstract
Endoscopy is a medical operation in which a camera is sent into the patient's body and the physician starts taking pictures at specified times. In the traditional endoscopic procedure, a camera is sent into the body by a guiding wire. This can cause severe pain to the patient. In the newer method, a camera is mounted on a small capsule and the patient swallows the capsule. Then the camera inside the capsule starts taking photos and sends them out. This procedure, in addition to being painless, allows the physician to access the innermost parts of the body or the digestive tract.In capsule endoscopy, unlike the older method, one has to find the position and orientation of the capsule at any...
Synthesis of Magnetic Nanocomposite Scaffolds by Electrospinning Method and Study of Drug Release Behavior
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor) ; Madaah Hosseini, Hamid Reza (Supervisor)
Abstract
Controlled release is a crucial factor in tissue engineering and cancer-therapy applications. The main purpose of current research is to synthesis smart magnetic nanocarriers for hydrophobic drug and embedding them in a fibrous platform for anti-cancer/ tissue engineering applications. In this regard, three different drug delivery systems of magnetic nanocolloid, magnetic fibers and hydrogels were studied. In the first phase, superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized and then were modified using oleic acid and thermo-sensitive polymer of pluronic F127/F68. After characterization of this composite, Response Surface Methodology (RSM) was applied to model the lower...
Study on the Performance of Magnetic Nanoparticles in Hyper-thermic Treatment of Cancerous Tumors, by Heating an MRI Apparatus
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Nourani, Mohammad Reza (Supervisor)
Abstract
The aim of this study was to investigate the rate of increase in temperature of a phantom equivalent to body tissue by different groups of magnetic iron nanoparticles in the external magnetic field to kill cancer cells based on the hyperthermia method. To achieve this goal, three groups of dextran magnetic nanoparticles with different properties and reduced iron oxide-graphene oxide magnetic nanoparticles by M-rGO supercritical synthesis method were used. After XRD, FTIR, SEM, FESEM, VSM, TEM characterization tests, these materials were placed in a phantom made of agarose gel and with the same properties, in a magnetic field with fixed characteristics for all groups and during the process of...
Direct numerical simulation of magnetic particles suspended in a Newtonian fluid exhibiting finite inertia under SAOS
, Article Journal of Non-Newtonian Fluid Mechanics ; Volume 256 , 2018 , Pages 8-22 ; 03770257 (ISSN) ; Manzari, M. T ; Fatehi, R ; Sharif University of Technology
Elsevier B.V
2018
Abstract
A direct numerical simulation approach is utilized to understand the oscillatory shear rheology of a confined suspension of magnetic chains formed by paramagnetic circular cylinders under the influence of an external magnetic field. The common assumption of gap-spanning chains made in the literature is relaxed in this work, so that a fully suspended (periodic) array of magnetic chains is formed. In this sense, the effective rheological parameters are only influenced through a layer of fluid adjacent to the walls. All tests are conducted at very low but finite particle Reynolds numbers, and typical inertial effects are discussed. The main aim of the present study is to investigate the...
A novel hydro magnetic micro-pump and flow controller
, Article 6th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM2008, Darmstadt, 23 June 2008 through 25 June 2008 ; Issue PART B , June , 2008 , Pages 1537-1544 ; 0791848345 (ISBN); 9780791848340 (ISBN) ; Esmaily Moghadam, M ; Shafii, M. B ; ASME ; Sharif University of Technology
2008
Abstract
In order to deal with the limitations of micro-pumps and micro-valves and meet the advantages of magnetic systems a novel plan is described here. The idea behind the plan is that magnetic particles, mixed and dispersed in a carrier liquid, can be accumulated and retained at specific sites to form pistons in a micro-tube using some external magnetic field sources along the tube. In other words, using some solenoids and switching them on and off, in a specific order and period, causes the desired external magnetic field variation through the tube. Changing the period and the mode of activation and deactivation of the solenoids, which are called switching time and switching mode, respectively,...
Deriving an analytical model for hydro-magnetic micro flow controller
, Article 6th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM2008, Darmstadt, 23 June 2008 through 25 June 2008 ; Issue PART B , June , 2008 , Pages 1139-1146 ; 0791848345 (ISBN); 9780791848340 (ISBN) ; Shafii, M. B ; ASME ; Sharif University of Technology
2008
Abstract
Fluid control, namely pumping and valving, is a critical factor in the performance of micro-fluidic systems. In recent years a variety of micro-fluidic systems are developed for the purpose of miniaturizing fluid handling, and chemical analysis to develop Lab On a Chip (LOC) technology. The mentioned facts resulted in design and fabrication of a novel hydromagnetic flow controller. The idea behind this device is that magnetic particles, mixed and dispersed in a carrier liquid, can be accumulated in the form of a piston. Depending upon dragging speed of these pistons, which itself is a function of switching time, this device can be used to either increase (pumping) or decrease (valving) the...
Synthesis and characterization of CaO-P2O5-SiO2-Li2O-Fe2O3 bioactive glasses: The effect of Li2O-Fe2O3 content on the structure and in-vitro bioactivity
, Article Journal of Non-Crystalline Solids ; 2018 ; 00223093 (ISSN) ; Yazdanpanah, A ; Ansari Hamedani, A ; Ramedani, A ; Moztarzadeh, F ; Sharif University of Technology
Elsevier B.V
2018
Abstract
CaO-P2O5-SiO2-Li2O-Fe2O3 magnetic bioactive glasses were prepared through an optimized sol-gel method. This study was emphasized on the effects of magnetic content addition on the bioactive glass properties. As the need arises, we study synthesized magnetic bioactive glass physical, rheological, and biocompatible properties. The morphology and composition of these glasses were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The particle size was also determined using a laser particle size analyzer (LPSA). The thermal measurements were put through using Differential thermal analysis (DTA). In order to evaluate the...
Hydromagnetic micropump and flow controller. part a: experiments with nickel particles added to the water
, Article Experimental Thermal and Fluid Science ; Volume 33, Issue 6 , 2009 , Pages 1021-1028 ; 08941777 (ISSN) ; Shafii, M. B ; Alavi Dehkordi, E ; Sharif University of Technology
2009
Abstract
The novel idea of the Hydromagnetic Micropump and Flow Controller (HMFC) is used in this paper to construct a laboratory setup capable of bidirectional pumping and controlling the flow in microtubes. A laboratory setup, which contains no moving parts, is integrated with a pressure-driven flow setup to make the presented HMFC device. The device operation is based on controllable motion of magnetic particles, added to the carrier fluid, caused by the magnetic field, produced by solenoids located just next to the microtube. The magnitude of these forces is proportional to the strength and gradient of magnetic field which, in turn, is related to the electrical current and arrangement of the...
Cytotoxicity of uncoated and polyvinyl alcohol coated superparamagnetic iron oxide nanoparticles
, Article Journal of Physical Chemistry C ; Volume 113, Issue 22 , 2009 , Pages 9573-9580 ; 19327447 (ISSN) ; Simchi, A ; Imani, M ; Sharif University of Technology
2009
Abstract
Superparamagnetic iron oxide nanoparticles (SPION) are being increasingly used in various biomedical applications such as hyperthermia, cell and protein separation, enhancing resolution of magnetic resonance imaging, and drug delivery. However, the toxicity data for SPION are limited. In this study, uncoated and single polyvinyl alcohol coated SPION with high chemical reactivity (due to the bigger surface area) were synthesized using a coprecipitation method. Cytotoxicity of these magnetic nanoparticles and their ability to cause arrest in cell life-cycles was investigated. Interaction of these nanoparticles with adhesive mouse fibroblast cell line (L929) was probed using MTT assay. High...
Synthesis and characterization of CaO-P2O5-SiO2-Li2O-Fe2O3 bioactive glasses: The effect of Li2O-Fe2O3 content on the structure and in-vitro bioactivity
, Article Journal of Non-Crystalline Solids ; Volume 503-504 , 2019 , Pages 139-150 ; 00223093 (ISSN) ; Yazdanpanah, A ; Ansari Hamedani, A ; Ramedani, A ; Moztarzadeh, F ; Sharif University of Technology
Elsevier B.V
2019
Abstract
CaO-P2O5-SiO2-Li2O-Fe2O3 magnetic bioactive glasses were prepared through an optimized sol-gel method. This study was emphasized on the effects of magnetic content addition on the bioactive glass properties. As the need arises, we study synthesized magnetic bioactive glass physical, rheological, and biocompatible properties. The morphology and composition of these glasses were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The particle size was also determined using a laser particle size analyzer (LPSA). The thermal measurements were put through using Differential thermal analysis (DTA). In order to evaluate the...