Magnetic Force on Capsule Robot in Three-dimensional Rotating Magnetic Field with Gradient

2014 ◽  
Vol 50 (17) ◽  
pp. 1
Author(s):  
Yongshun ZHANG
2019 ◽  
Vol 97 (3) ◽  
pp. 163-168 ◽  
Author(s):  
Priyanka Sharma ◽  
Srinivasu V. Vallabhapurapu ◽  
Wei H. Ho ◽  
Nanjundaswamy M. Hemmaragala

The novel reactor has been designed to perform chemical reactions under the influence of a magnetic field generated by alternating magnetic poles as a function of time. The system was successfully employed to synthesize a series of 1,5-disubstituted-1,2,3-triazolines via the regioselective [3 + 2] cycloaddition reactions between alkyl/aryl azides and nitroolefins catalysed by Zepto (para magnetic ultra-blue carboxy functionalized) microspheres (bead diameter 2.5 μm). All of the reactions went smoothly without any adverse effect on nitro, cyano, thienyl, hydroxy, halogens, and ether functions at 25 ± 2 °C and afforded 82%–99% pure products at a magnetic field of 18.99 mT and an exposure time of 180–240 min. The influence of the magnetic force exerted on the magnetic materials was found to enhance the catalytic activity of microspheres. The catalyst could easily be separated by simple centrifugation, which could be reused for at least 15 runs with no loss in activity.


2017 ◽  
Vol 821 ◽  
pp. 266-295 ◽  
Author(s):  
J. Erdmanis ◽  
G. Kitenbergs ◽  
R. Perzynski ◽  
A. Cēbers

Magnetic droplets obtained by induced phase separation in a magnetic colloid show a large variety of shapes when exposed to an external field. However, the description of the shapes is often limited. Here, we formulate an algorithm based on three-dimensional boundary-integral equations for strongly magnetic droplets in a high-frequency rotating magnetic field, allowing us to find their figures of equilibrium in three dimensions. The algorithm is justified by a series of comparisons with known analytical results. We compare the calculated equilibrium shapes with experimental observations and find a good agreement. The main features of these observations are the oblate–prolate transition, the flattening of prolate shapes with the increase of magnetic field strength and the formation of starfish-like equilibrium shapes. We show both numerically and in experiments that the magnetic droplet behaviour may be described with a triaxial ellipsoid approximation. Directions for further research are mentioned, including the dipolar interaction contribution to the surface tension of the magnetic droplets, accounting for the large viscosity contrast between the magnetic droplet and the surrounding fluid.


1971 ◽  
Vol 43 ◽  
pp. 505-511
Author(s):  
J. Jakimiec

At the beginning the problem of constructing the three-dimensional magnetohydrostatic models of the photospheric layers in sunspots is discussed in some detail. It is pointed out that the construction of such models by solving the set of equations of magnetohydrostatics cannot be effectively carried out.In order to solve the difficulties a suitable method of determining the distribution of the magnetic force in sunspots from measurements of the magnetic field has been worked out. Tentative results of the computations are presented.General features of the distribution of the magnetic force in the photospheric layers of stable sunspots are discussed. It is pointed out that significant magnetic forces are necessary in the penumbra; they secure its transversal equilibrium, but are rather unimportant for its vertical structure. And it is quite probable that the magnetic field in the umbras of stable spots is nearly potential or force-free down to the photospheric level.


2009 ◽  
Vol 416 ◽  
pp. 406-410 ◽  
Author(s):  
Xin Gai Yao ◽  
Yan Hong Ding ◽  
Gang Ya ◽  
Wei Wei Liu ◽  
Yuan Zhang

In the paper, a new method of using rotating magnetic field generated by a stator of alternative electromotor to finish the inner surface of tube-type workpiece is proposed. Force and movements of magnetic abrasive are analyzed. The finishing mechanism is analyzed and the sliding, friction and scratching between magnetic abrasives and the workpiece inner surface may be main factors of material removal as the non-mechanical relative motion is produced.


2021 ◽  
Vol 11 (11) ◽  
pp. 5292
Author(s):  
Eunsoo Jung ◽  
Jaekwang Nam ◽  
Wonseo Lee ◽  
Jongyul Kim ◽  
Gunhee Jang

We developed a crawling magnetic robot (CMR), which can stably navigate and perform biopsies remotely in tubular environments by controlling a magnetic field. The CMR is composed of a crawling part and a biopsy part. The crawling part allows the CMR to crawl forward and backward via an asymmetric friction force generated by an external precessional magnetic field. The biopsy part closes or opens the cover of a needle to use the biopsy needle selectively with the control of the external precessional magnetic field. The cover of the biopsy part prevents damage to the tubular environments because the biopsy needle is inside the cover while the CMR is navigating. We developed the design of the proposed CMR using magnetic torque constraints and a magnetic force constraint, and then we fabricated the CMR with three-dimensional printing technology. Finally, we conducted an experiment to measure the CMR’s puncturing force with a load cell and conducted an experiment in a Y-shaped watery glass tube with pseudo-tissue to verify the crawling motion, the uncovering and covering motion of the biopsy needle, and the CMR’s ability to extract tissue with the biopsy needle.


Author(s):  
S. Morteza Mousavi ◽  
Mousa Farhadi ◽  
Kurosh Sedighi

In this paper, biomagnetic fluid flow in a three-dimensional channel in the presence of obstacles and under the influence of a magnetic field is studied numerically. The magnetic field is generated by a wire carrying electric current. The mathematical model of biomagnetic fluid dynamics which is consistent with the principles of ferrohydrodynamics and magnetohydrodynamics is used for the problem formulation. A computational grid which accurately covers the magnetic force is used for the discretisation of computational domain. The flow field is studied in the different arrangements of the obstacles and diverse magnetic field strengths. The results show that the flow pattern is drastically influenced by the applied magnetic field. Applying the magnetic field causes a secondary flow that affects the velocity distribution considerably. The magnetic force also reduces the maximum axial velocity. Furthermore, the magnetic field has a considerable impact on the recirculation zones behind the obstacles. The magnetic field makes the recirculation zones smaller. This study indicates that applying the magnetic field increases the axial drag coefficients of the obstacles significantly (in a case, by 40.15%).


2021 ◽  
Author(s):  
Mehdi Mohammadi Shemirani

A three-dimensional numerical simulation was conducted to study the effect of a rotating magnetic (RMF) field on the fluid flow, heat transfer and mass transfer in the presence of various gravity levels by utilizing the traveling solvent method (TSM). The presence of the RMF suppressed the buoyancy convection in the GE₀.₉₈ Si₀.₀₂ solution zone in order to get homogeneity with a flat growth interface. It was found that the intensity of the flow at the centre of the crucible decreased at a faster rate compared to the flow near the walls when increasing magnetic field intensity is combined with a certain rotational speed. This behavior created a stable and uniform silicon distribution in the horizontal plane near the growth interface in the terrestrial condition. Different magnetic field intensities for different rotational speeds were examined in both terrestrial and micro-gravity conditions. The effects of residual acceleration, known as G-jitter, on board the International Space Station and European Space Orbiter were also investigated.


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