scholarly journals External Magnetic Field Measurements in UME Kibble Balance

ACTA IMEKO ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 33
Author(s):  
Haci Ahmedov ◽  
Beste Korutlu ◽  
Lev Dorosinskiy ◽  
Recep Orhan ◽  
Ozlen Tuncel
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Vertical Direction ◽  
Field Measurements ◽  
Magnetic Flux Density ◽  
National Metrology Institute ◽  
Mass Unit ◽  
Long Term Stability ◽  
Faraday’S Law ◽  
Definition Of

The new definition of kilogram in terms of the fixed value of Planck constant ensures the long-term stability of SI mass unit and enables traceability from more than one source. Kibble balance experiments offer an effective primary realization method for the new definition of kilogram. Kibble Balance apparatus operating at National Metrology Institute of Turkey is designed with a stationary coil and an oscillating magnet. In contradistinction to traditional moving coil Kibble balance experiments, external magnetic field brings an asymmetry between the Ampere’s law of force and the Faraday’s law of induction in moving magnet experiments. In this paper, we develop a method based on the external magnetic flux density difference measurements in vertical direction to take into account the effect of the external magnetic field on the realization of kilogram. The proposed model in this approach fits well with the data such that the kilogram realization requirement is met within the accuracy of the measuring instrument.

scholarly journals Fault Identification on a Fuel Cell by 3-D Current Density Reconstruction From External Magnetic Field Measurements

2019 ◽  
Vol 55 (6) ◽  
pp. 1-5 ◽  
Author(s):  
Lyes Ifrek ◽  
Olivier Chadebec ◽  
Sebastien Rosini ◽  
Gilles Cauffet ◽  
Yann Bultel ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Fuel Cell ◽  
External Magnetic Field ◽  
Current Density ◽  
Field Measurements ◽  
Fault Identification ◽  
Magnetic Field Measurements

The Thermoelectric-Hydromagnetic Pump

1964 ◽  
Vol 86 (2) ◽  
pp. 166-168 ◽  
Author(s):  
J. F. Osterle ◽  
S. W. Angrist
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Pressure Rise ◽  
Maximum Efficiency ◽  
Magnetic Flux Density ◽  
Optimum Thickness ◽  
Pumping Power ◽  
Electrically Conducting

A thermally powered pump for fluids which are electrically conducting, which utilizes the Lorentz force between an electric current induced by the Seebeck effect, and an external magnetic field is examined. The pressure rise in the pump is found to be proportional to the magnetic flux density while the flow rate is found to be inversely proportional to the magnetic flux density. Thus the pumping power and efficiency (both being proportional to the product of pressure rise and flow) are independent of the applied magnetic field. Calculations for a pump with constantan walls handling sodium and utilizing a temperature difference of 300 deg C show that a maximum efficiency of close to seven-tenths of a percent is possible. If the same pump is constructed with optimum thickness walls made of the semiconductor AgSbTe2, it would have an efficiency of nearly six percent.

scholarly journals Current Distribution Identification in Fuel Cell Stacks From External Magnetic Field Measurements

2013 ◽  
Vol 49 (5) ◽  
pp. 1925-1928 ◽  
Author(s):  
Mathieu Le Ny ◽  
Olivier Chadebec ◽  
Gilles Cauffet ◽  
Jean-Marc Dedulle ◽  
Yann Bultel ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Fuel Cell ◽  
External Magnetic Field ◽  
Current Distribution ◽  
Field Measurements ◽  
Magnetic Field Measurements

Neutron–antineutron oscillation and discrete symmetries

2018 ◽  
Vol 33 (31) ◽  
pp. 1844016 ◽  
Author(s):  
Zurab Berezhiani ◽  
Arkady Vainshtein
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Text Classification ◽  
Discrete Symmetries ◽  
Rotational Invariance ◽  
Baryon Charge ◽  
Free Particles ◽  
Definition Of ◽  
Charge Formula

We analyze status of [Formula: see text], [Formula: see text] and [Formula: see text] discrete symmetries in application to neutron–antineutron transitions breaking conservation of baryon charge [Formula: see text] by two units. At the level of free particles, all these symmetries are preserved. This includes [Formula: see text] reflection in spite of the opposite internal parities usually ascribed to neutron and antineutron. Explanation, which goes back to the 1937 papers by Majorana and Racah, is based on a definition of parity satisfying [Formula: see text], instead of [Formula: see text], and ascribing [Formula: see text] to both, neutron and antineutron. We apply this to [Formula: see text], [Formula: see text] and [Formula: see text] classification of six-quark operators with [Formula: see text]. It allows to specify operators contributing to neutron–antineutron oscillations. Remaining operators contribute to other [Formula: see text] processes and, in particular, to nuclei instability. We also show that presence of external magnetic field does not induce any new operator mixing the neutron and antineutron provided that rotational invariance is not broken.

Deterministic Spin–Orbit Torque Switching of a Perpendicularly Polarized Magnet Using Wedge Shape of the Magnet

SPIN ◽  
2016 ◽  
Vol 06 (02) ◽  
pp. 1640008
Author(s):  
Debanjan Bhowmik ◽  
Sayeef Salahuddin
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Data Storage ◽  
Vertical Direction ◽  
Anisotropy Axis ◽  
Spin Orbit ◽  
Micromagnetic Simulations ◽  
Wedge Shape ◽  
Memory Applications ◽  
Deterministic Switching

Spin–orbit torque provides an efficient way to switch magnets for low power memory applications by reducing the current density needed to switch the magnetization. Perpendicularly polarized magnets are preferred for high density data storage applications because of their high thermal stability in scaled dimensions. However, spin–orbit torque cannot switch a perpendicularly polarized magnet deterministically from up to down and down to up in the absence of an external magnetic field because spin–orbit torque alone cannot break the symmetry of the system. This poses a severe challenge to the applicability of spin–orbit torque for memory devices. In this paper, we show through micromagnetic simulations that when spin–orbit torque is applied on a magnet with a wedge shape, the moments of the magnet are aligned in-plane. On removal of the spin–orbit torque the moments deterministically evolve to vertically upward or downward direction because the anisotropy axis of the magnet is tilted away from the vertical direction owing to the wedge shape of the magnet. Thus, spin–orbit torque driven deterministic switching of the magnet in the absence of an external magnetic field is possible.

SURFACE BARRIER IN THE MIXED STATE OF ANISOTROPIC SUPERCONDUCTOR

1993 ◽  
Vol 07 (12) ◽  
pp. 841-847
Author(s):  
T. KRZYSZTON
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Flux Density ◽  
Surface Barrier ◽  
Anisotropy Axis ◽  
Anisotropic Superconductor ◽  
Applied External Magnetic Field ◽  
London Theory

In the framework of London theory, the problem of equilibrium between magnetic flux density in the anisotropic superconductor and the applied external magnetic field is studied. The Gibbs free energy of a fluxoid in the presence of magnetic flux density in the sample is calculated. As a result, critical entry and exit fields are calculated and their dependence upon the angle which makes anisotropy axis and the direction of an external magnetic field.

External Magnetic Field Control during EDM of a Permanent Magnet

2014 ◽  
Vol 1017 ◽  
pp. 806-811
Author(s):  
Hideki Takezawa ◽  
Nobuhiro Yokote ◽  
Naotake Mohri
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Electrical Discharge Machining ◽  
Magnetic Flux Density ◽  
Internal Temperature ◽  
Set Up ◽  
The Magnetic Field

The effect of changes in the magnetic field on the magnetic flux density during the electrical discharge machining (EDM) of a permanent magnet is reported. During EDM of the permanent magnet, a second magnet for the external magnetic field was set up, and the internal temperature and surface magnetic flux density on the opposite surface of the permanent magnet during machining were evaluated. It was found that even though the internal temperature of the magnet remained unchanged, the surface magnetic flux density changed when the external magnetic field was varied. In addition, the magnetic field generated by the magnet changed when a plate with high permeability was pressed onto the surface of the permanent magnet.

scholarly journals 2D and 3D fault basis for fuel cell diagnosis by external magnetic field measurements

2017 ◽  
Vol 79 (2) ◽  
pp. 20901 ◽  
Author(s):  
Lyes Ifrek ◽  
Gilles Cauffet ◽  
Olivier Chadebec ◽  
Yann Bultel ◽  
Sébastien Rosini ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Inverse Problem ◽  
Fuel Cell ◽  
External Magnetic Field ◽  
Current Density ◽  
Field Measurements ◽  
Magnetic Field Measurements ◽  
Uniqueness Of The Solution ◽  
Ill Posed ◽  
Value Decomposition

An original approach used for the identification of faults in fuel cell stacks is presented. It is based on the 3D reconstruction of the current density from external magnetic field measurements which is an ill-posed magnetostatic linear inverse problem. A suitable and original current density and magnetic field basis are proposed in order to define both local and global faults on a fuel cell stack. The inverse problem is regularized by truncated singular value decomposition (SVD) to ensure the uniqueness of the solution.

Magnetic Microparticles for Endovascular Aneurysm Treatment: In Vitro and In Vivo Experimental Results

Neurosurgery ◽  
2011 ◽  
Vol 68 (5) ◽  
pp. 1388-1398 ◽  
Author(s):  
Johanna Oechtering ◽  
Peter J. Kirkpatrick ◽  
Alexander G. K. Ludolph ◽  
Franz J. Hans ◽  
Bernd Sellhaus ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Observational Period ◽  
Magnetic Microparticles ◽  
Term Stability ◽  
Long Term Stability ◽  
Aneurysm Model

AbstractOBJECTIVE:Endovascular treatment of intracranial aneurysms employing endosaccular coiling can be associated with aneurysm perforation, coil herniation or incomplete obliteration fueling the interest to investigate novel endovascular techniques. We aimed to test a novel embolization material in experimental aneurysms in vitro and in vivo whereby intra-arterially administered magnetic microparticles (MMPs) are navigated into the lumen of vascular aneurysms with assistance from an external magnetic field.METHODS:MMPs are core-shell particles suspended in saline that have a shell made of a polymeric material and a core made of magnetite (Fe3O4). They have a diameter of 1.4 μm. During MMP administration via a microcatheter, a magnetic field was applied externally to direct the particles with the use of a solid-state neodymium magnet. Experiments were performed in a perfused silicone vessel and aneurysm model to evaluate application techniques and fluid dynamics and in the elastase aneurysm model in rabbits to evaluate in vivo compatibility, including multiorgan histological examinations and long-term stability of aneurysm embolization.RESULTS:It was possible to steer and hold the MMPs within the aneurismal cavity where they occluded the lumen progressively. After removal of the external magnetic field, the results remained stable in vivo for the remainder of the observational period (30 minutes); after a 12-week observational period, recanalization of the aneurysm occurred.CONCLUSION:MMPs can be magnetically directed into aneurysms, allowing short-term obliteration. Although the method has yet to show reliable long-term stability, these experiments provide proof of concept, encouraging further investigation of intravascular magnetic compounds.

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