scholarly journals Magnetic Guiding with Permanent Magnets: Concept, Realization and Applications to Nanoparticles and Cells

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2708
Author(s):  
Peter Blümler
Keyword(s):  
Magnetic Fields ◽  
Permanent Magnets ◽  
Imaging Techniques ◽  
Superparamagnetic Nanoparticles ◽  
Force Generation ◽  
Magnetic Imaging ◽  
Nanoparticle Dispersions ◽  
First Results ◽  
Macroscopic Objects ◽  
Orientation Movement

The idea of remote magnetic guiding is developed from the underlying physics of a concept that allows for bijective force generation over the inner volume of magnet systems. This concept can equally be implemented by electro- or permanent magnets. Here, permanent magnets are in the focus because they offer many advantages. The equations of magnetic fields and forces as well as velocities are derived in detail and physical limits are discussed. The special hydrodynamics of nanoparticle dispersions under these circumstances is reviewed and related to technical constraints. The possibility of 3D guiding and magnetic imaging techniques are discussed. Finally, the first results in guiding macroscopic objects, superparamagnetic nanoparticles, and cells with incorporated nanoparticles are presented. The constructed magnet systems allow for orientation, movement, and acceleration of magnetic objects and, in principle, can be scaled up to human size.

scholarly journals Reversible rearrangement of magnetic nanoparticles in solution studied using time-resolved SAXS method

2019 ◽  
Vol 26 (4) ◽  
pp. 1294-1301
Author(s):  
Lanqing Huang ◽  
Jingeng Mai ◽  
Qihui Zhu ◽  
Zhen Guo ◽  
Siying Qin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Beads ◽  
Permanent Magnets ◽  
Superparamagnetic Nanoparticles ◽  
Shanghai Synchrotron Radiation Facility ◽  
Time Resolved ◽  
X Ray ◽  
Quantitative Measurements

Superparamagnetic nanoparticles have broad applications in biology and medicines. Quantitative measurements of magnetic beads in solution are essential in gaining comprehensive understanding of their dynamics and developing applications. Here, using synchrotron X-ray sources combined with well controlled magnetic fields, the results from small-angle X-ray scattering (SAXS) experiments on superparamagnetic particles in solution under the influence of external magnetic fields are reported. The particles mostly remain in monodispersed states and the linear aggregates tend to be aligned with the external magnetic field. After removing the magnetic fields, the superparamagnetic nanoparticles quickly recover to their original states indicating high reversibility of the rearrangement under the control of a magnetic field. The external magnetic field instrument composed of paired permanent magnets is integrated into the SAXS beamline at the Shanghai Synchrotron Radiation Facility providing a platform for studying time-resolved dynamics induced by magnetic fields.

Thermal Energy Dissipation by SiO2-Coated Plasmonic-Superparamagnetic Nanoparticles in Alternating Magnetic Fields

2013 ◽  
Vol 25 (22) ◽  
pp. 4603-4612 ◽  
Author(s):  
Georgios A. Sotiriou ◽  
Michelle A. Visbal-Onufrak ◽  
Alexandra Teleki ◽  
Eduardo J. Juan ◽  
Ann M. Hirt ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Magnetic Fields ◽  
Thermal Energy ◽  
Superparamagnetic Nanoparticles ◽  
Thermal Energy Dissipation ◽  
Alternating Magnetic Fields

scholarly journals Development of an in-situ SEOP 3 He Neutron Spin Filter for Magnetic Imaging Techniques

2017 ◽  
Vol 88 ◽  
pp. 231-236 ◽  
Author(s):  
H. Hayashida ◽  
K. Hiroi ◽  
T. Oku ◽  
H. Kira ◽  
K. Sakai ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Neutron Spin ◽  
Spin Filter ◽  
Magnetic Imaging

scholarly journals Effect of Magnetic Nanofluids on the Performance of a Fin-Tube Heat Exchanger

2021 ◽  
Vol 11 (19) ◽  
pp. 9261
Author(s):  
Yun-Seok Choi ◽  
Youn-Jea Kim
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Magnetic Fields ◽  
Heat Transfer Performance ◽  
Permanent Magnets ◽  
Convective Heat Transfer Coefficient ◽  
Transfer Performance ◽  
Tube Heat Exchanger ◽  
Improve Heat Transfer ◽  
Fin Tube

As electrical devices become smaller, it is essential to maintain operating temperature for safety and durability. Therefore, there are efforts to improve heat transfer performance under various conditions, such as using extended surfaces and nanofluids. Among them, cooling methods using ferrofluid are drawing the attention of many researchers. This fluid can control the movement of the fluid in magnetic fields. In this study, the heat transfer performance of a fin-tube heat exchanger, using ferrofluid as a coolant, was analyzed when external magnetic fields were applied. Permanent magnets were placed outside the heat exchanger. When the magnetic fields were applied, a change in the thermal boundary layer was observed. It also formed vortexes, which affected the formation of flow patterns. The vortex causes energy exchanges in the flow field, activating thermal diffusion and improving heat transfer. A numerical analysis was used to observe the cooling performance of heat exchangers, as the strength and number of the external magnetic fields were varying. VGs (vortex generators) were also installed to create vortex fields. A convective heat transfer coefficient was calculated to determine the heat transfer rate. In addition, the comparative analysis was performed with graphical results using contours of temperature and velocity.

Influence of Permanent Magnets Installation Approach on the Torque of а Magneto-Rheological Disk Brake

2021 ◽  
Vol 105 ◽  
pp. 184-193
Author(s):  
Ilya Aleksandrovich Frolov ◽  
Andrei Aleksandrovich Vorotnikov ◽  
Semyon Viktorovich Bushuev ◽  
Elena Alekseevna Melnichenko ◽  
Yuri Viktorovich Poduraev
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Materials ◽  
Permanent Magnets ◽  
Magnetorheological Fluid ◽  
Simulation Modelling ◽  
Disc Brake ◽  
Large Area ◽  
Braking Torque ◽  
The Magnetic Field

Magnetorheological braking devices function due to the organization of domain structures between liquid and solid magnetic materials under the action of an electromagnetic or magnetic field. The disc is most widely used as a rotating braking element that made of a solid magnetic material due to the large area of contact with a magnetorheological fluid. Many factors affect the braking characteristics of the magnetorheological disc brake. Specifically, the value of the magnetic field and how the field is distributed across the work element is significantly affected at the braking torque. There are different ways to generate a magnetic field. In this study, the method of installation of permanent magnets into the construction, allowing to increase the braking torque of the magnetorheological disc brake is proposed. Simulation modelling showing the distribution of the magnetic field across the disk depending on the installation of permanent magnets with different pole orientations were carried out. The model takes into account the possibility of increasing the gap between solid magnetic materials of the structure, inside them which the magnetorheological fluid is placed. Comparative estimation of the distribution of the magnetic fields depending on the chosen method of installation of permanent magnets with different orientations of their poles is carried out. Further research is planned to focus on a comparative assessment of the distribution of magnetic fields depending on the selected material of the braking chamber.

scholarly journals Experimental Study of the Orientation of Magnetic Fields in the Corona

1971 ◽  
Vol 43 ◽  
pp. 580-587 ◽  
Author(s):  
P. Charvin
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Magnetic Fields ◽  
Large Scale ◽  
Coronal Line ◽  
Magnetic Structures ◽  
Polarization Measurements ◽  
First Results

We present polarization measurements obtained in 1970 in the green coronal line with a new coronameter located at the Pic du Midi. The analysis of these data has been conducted with the theory given by the writer in 1964 and 1965. It appears that magnetic field orientations in the Corona can be deduced from the above measurements. First results showing large scale magnetic structures are presented.

scholarly journals Development of a magnetic tracking system for monitoring soil movements induced by geohazards

2019 ◽  
Vol 92 ◽  
pp. 17007 ◽  
Author(s):  
Xiaoyu Chen ◽  
Rolando P. Orense
Keyword(s):  
Magnetic Fields ◽  
Permanent Magnets ◽  
Tracking System ◽  
Soil Liquefaction ◽  
Small Scale ◽  
Interior Point Algorithm ◽  
Tracking Accuracy ◽  
Tracking Errors ◽  
Magnetic Tracking ◽  
Soil Movements

In the study of geotechnical hazards, such as soil liquefaction and landslides, the analysis of soil movements is always one of the major preoccupations. An efficient movement sensing technique requires the tracking of subsurface soil for the purpose of examining the mechanism involved. A magnetic tracking system is therefore proposed, with permanent magnets as trackers and magnetometers as receivers. When permanent magnets, deployed within the soil to serve as excitation sources, move with soil body during a geotechnical event, they generate static magnetic fields whose flux densities are related with the positions and orientations of the magnets. Magnetometers are used as receivers to detect the generated magnetic fields, which can be further used in calculating the magnets' locations and orientations based on appropriately developed algorithms. Comparison between situations where the trackers are exposed to air and embedded within soil was conducted to evaluate the influence of soil (wet and dry) on the tracking accuracy. Also, multi-objective tracking is realized by using the particle swarm optimization (PSO) technique combined with interior-point algorithm. The tracking errors are evaluated and applications of the proposed system in small-scale laboratory tests for geohazards are discussed.

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