MAGNETORHEOLOGICAL CHARACTERIZATION OF HOLLOW POLYMER/MAGNETITE MICROSPHERICAL COMPOSITE

2009 ◽  
Vol 23 (17) ◽  
pp. 3613-3618 ◽  
Author(s):  
FEI FEI FANG ◽  
JI HYE KIM ◽  
HYOUNG JIN CHOI
Keyword(s):  
Magnetic Field ◽  
Magnetic Property ◽  
External Magnetic Field ◽  
Shear Viscosity ◽  
Colloidal Particles ◽  
Rheological Characteristics ◽  
Carrier Liquid ◽  
Magnetic Field Generator ◽  
Mr Characteristics

Magnetorheological (MR) suspensions, composed of colloidal particles dispersed in a carrier liquid, possess tunable rheological characteristics by applying an external magnetic field, showing dramatic changes of yield stress and shear viscosity caused by transformation between solid-like to liquid-like state. As a new MR material, we synthesized hollow polystyrene/magnetite (PS/Fe3O4) microspherical composite. Morphology of the PS obtained and the loaded magnetite were examined via SEM, and TGA spectra confirmed the composition. Magnetic property was tested by VSM data. MR characteristics of MR suspension based on PS / Fe 3 O 4 composites were studied via both steady shear and oscillatory tests using a rotational rheometer equipped with a magnetic field generator.

scholarly journals Simultaneous polydirectional transport of colloidal bipeds

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Mahla Mirzaee-Kakhki ◽  
Adrian Ernst ◽  
Daniel de las Heras ◽  
Maciej Urbaniak ◽  
Feliks Stobiecki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
External Field ◽  
Colloidal Particles ◽  
Addition Reaction ◽  
Lab On A Chip ◽  
Magnetic Pattern ◽  
Colloidal Spheres ◽  
Colloidal Science ◽  
Colloidal Rods

Abstract Detailed control over the motion of colloidal particles is relevant in many applications in colloidal science such as lab-on-a-chip devices. Here, we use an external magnetic field to assemble paramagnetic colloidal spheres into colloidal rods of several lengths. The rods reside above a square magnetic pattern and are transported via modulation of the direction of the external magnetic field. The rods behave like bipeds walking above the pattern. Depending on their length, the bipeds perform topologically distinct classes of protected walks. We design parallel polydirectional modulation loops of the external field that command up to six classes of bipeds to walk on distinct predesigned paths. Using such loops, we induce the collision of reactant bipeds, their polymerization addition reaction to larger bipeds, the separation of product bipeds from the educts, the sorting of different product bipeds, and also the parallel writing of a word consisting of several letters. Our ideas and methodology might be transferred to other systems for which topological protection is at work.

Synthesis and Characterization of Cobalt-Nickel Nanowires Formed under External Magnetic Field

2015 ◽  
Vol 799-800 ◽  
pp. 120-124 ◽  
Author(s):  
Mary Donnabelle L. Balela ◽  
Lalaine M. Dulin ◽  
Erica A. Garcia ◽  
M. Janelle H. Tica
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Cobalt Nickel ◽  
Nickel Nanowires ◽  
Face Centered

Cobalt-nickel (Co-Ni) nanowires were formed by electroless deposition in ethylene glycol under external magnetic field. The effects of initial Co (II) and Ni (II) concentration on the surface and morphology of the synthesized nanowires were investigated by x-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. An increase in the Co (II) concentration resulted in increase in diameter of the nanowires. However, the length of nanowires was observed to decrease. Higher Co (II) concentration resulted in a mixture of hexagonal close-packed and face-centered cubic Co-Ni nanowires. X-ray diffraction revealed that crystal growth occurred when the nanowires are annealed at 653 K for 10h.

Magnetorheological Characterization of Polymer-Iron Composite Suspensions

2004 ◽  
Vol 449-452 ◽  
pp. 1201-1204 ◽  
Author(s):  
Min Seong Cho ◽  
Hyoung Jin Choi
Keyword(s):  
Magnetic Field ◽  
Parallel Plate ◽  
Suspension Polymerization ◽  
Measuring System ◽  
Composite Particles ◽  
Dispersed Phase ◽  
Mr Fluids ◽  
Polymerization Method ◽  
Mr Characteristics

Composite particles (CIPMMA) of carbonyl iron (CI) and poly (methyl methacrylate) (PMMA) were prepared by a suspension polymerization method using CI dispersions in MMA monomer, and these were adopted as dispersed phase of magnetorheological (MR) fluids. The CIPMMA can resolve several problems of MR fluids having CI alone such as severe sedimentation and poor dispersion stability. Flow and viscelastic properties of the MR fluids were analyzed via a rotational rheometer equipped with a magnetic field supplier using measuring system of a parallel plate. The MR characteristics like yield stress were affected by the CI contents in the composite particles.

Effects of external magnetic field on the morphology and magnetic property of BiFeO3 particles prepared by hydrothermal synthesis

2013 ◽  
Vol 102 (8) ◽  
pp. 082901 ◽  
Author(s):  
L. Hou ◽  
K. H. Zuo ◽  
Q. B. Sun ◽  
Z. M. Ren ◽  
Y. P. Zeng ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Property ◽  
Hydrothermal Synthesis ◽  
External Magnetic Field

Secondary resonance magnetic force microscopy using an external magnetic field for characterization of magnetic thin films

2015 ◽  
Vol 107 (10) ◽  
pp. 103110 ◽  
Author(s):  
Dongzi Liu ◽  
Kangxin Mo ◽  
Xidong Ding ◽  
Liangbing Zhao ◽  
Guocong Lin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
External Magnetic Field ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Magnetic Thin Films ◽  
Secondary Resonance ◽  
Force Microscopy

Characteristics of Ultrasound Propagation in a Magnetic Fluid Under Uniform Magnetic Field

2003 ◽  
Author(s):  
Masaaki Motozawa ◽  
Tatsuo Sawada
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fluid ◽  
Uniform Magnetic Field ◽  
Colloidal Particles ◽  
Magnetic Field Intensity ◽  
Magnetic Field Direction ◽  
Ultrasound Propagation ◽  
Ultrasonic Propagation ◽  
The Magnetic Field

When an external magnetic field is applied to a magnetic fluid, some of the colloidal particles coagulate and form chain-like clusters. Properties of ultrasonic propagation wave are changed by these chain-like clusters. We carried out measurement of the ultrasonic propagation velocity in a magnetic fluid. Measurement were made by changing the magnetic field intensity from 0 mT to 570 mT, and the angle between the magnetic field direction and direction of the ultrasound propagation from 0° to 180°. The ultrasound frequencies were 1 MHz, 2 MHz and 4 MHz. Some of experimental results for the characteristics of ultrasound propagation in a magnetic fluid under a uniform magnetic field were reported.

Characterization of optical trap for metallic particles using external magnetic field

2011 ◽  
Author(s):  
Vivek S. Jadhav ◽  
Wasim Sayyad ◽  
G. R. Kulkarni ◽  
B. M. Jaffar Ali
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Optical Trap ◽  
Metallic Particles
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