Electromagnetic induction in terms of the Maxwell force instead of magnetic flux

1999 ◽  
Vol 146 (4) ◽  
pp. 182-193 ◽  
Author(s):  
C.J. Carpenter
Keyword(s):  
Magnetic Flux ◽  
Electromagnetic Induction

scholarly journals Passive Magnetic-Flux-Concentrator Based Electromagnetic Targeting System for Endobronchoscopy

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5105
Author(s):  
Chen ◽  
Lin ◽  
Chang ◽  
Cheng ◽  
Chen ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Electromagnetic Induction ◽  
Bronchial Tree ◽  
Silicon Steel ◽  
Induced Voltage ◽  
High Permeability ◽  
Tree Model ◽  
Steel Sheets ◽  
Pattern Change ◽  
Flux Concentrator

In this paper, we demonstrate an innovative electromagnetic targeting system utilizing a passive magnetic-flux-concentrator for tracking endobronchoscope used in the diagnosis process of lung cancer tumors/lesions. The system consists of a magnetic-flux emitting coil, a magnetic-flux receiving electromagnets-array, and high permeability silicon-steel sheets rolled as a collar (as the passive magnetic-flux-concentrator) fixed in a guide sheath of an endobronchoscope. The emitting coil is used to produce AC magnetic-flux, which is consequently received by the receiving electromagnets-array. Due to the electromagnetic-induction, a voltage is induced in the receiving electromagnets-array. When the endobronchoscope’s guide sheath (with the silicon-steel collar) travels between the emitting coil and the receiving electromagnets-arrays, the magnetic flux is concentrated by the silicon-steel collar and thereby the induced voltage is changed. Through analyzing the voltage–pattern change, the location of the silicon–steel collar with the guide sheath is targeted. For testing, a bronchial-tree model for training medical doctors and operators is used to test our system. According to experimental results, the system is successfully verified to be able to target the endobronchoscope in the bronchial-tree model. The targeting errors on the x-, y- and z-axes are 9 mm, 10 mm, and 5 mm, respectively.

A Discussion on recent advances in heavy electrical plant - Homopolar machines

1973 ◽  
Vol 275 (1248) ◽  
pp. 69-75 ◽  
Keyword(s):  
Magnetic Flux ◽  
High Power ◽  
Electromagnetic Induction ◽  
Electrical Machine ◽  
Practical Solution ◽  
Current Collection ◽  
Recent Advances ◽  
Ohmic Losses ◽  
Classical Work ◽  
Power Densities

The genesis of homopolar machines is to be found in Faraday’s classical work on electromagnetic induction, and the first hint of their major problem, that of current collection, is contained in the account of the famous disk experiment which is given in his diary. Work within the last two years has provided a practical solution to this century-old problem and, together with a realization that ohmic losses in a steel rotor can be compensated by reduced excitation losses, has permitted the construction of an all-steel homopolar machine with a capability in excess of 100 kW. The use of an all-steel construction enables the magnetic flux to be guided in such a way that many stages can be linked with the flux from a given number of turns and the power-rating greatly increased. The relatively short thermal paths within the machine permit these high-power densities without excessive temperature rises. Conceptual designs have been produced capable of powers of tens of megawatts, which employ magnetic flux densities that are familiar to the electrical machine engineer.

An Electromagnetic Targeting System With Semi-Circular Configuration for Navigating Endo-Bronchoscope

2019 ◽  
Author(s):  
Shao-Wei Hsu ◽  
Ching-Kai Lin ◽  
Chin-Chung Chen ◽  
Yun-Chien Cheng ◽  
Chen-Wei Chang ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Electromagnetic Induction ◽  
Silicon Steel ◽  
Mechanical Support ◽  
Initial State ◽  
Circular Configuration ◽  
Flux Concentrator

Abstract In this paper, we present an electromagnetic targeting system with semi-circular configuration for navigating endo-bronchoscope. This system consists of a magnetic-flux emitting electromagnets-arrays fixed on a semi-circular mechanical-support, magnetic-flux receiving electromagnets, and a magnetic-flux concentrator (i.e., silicon-steel collar) which fixed on distal end of a guide sheath of the endo-bronchoscope. In initial state, when the emitting electromagnets produce magnetic flux in sequence, the receiving electromagnets receive the magnetic flux and consequently produce voltage outputs by the electromagnetic induction. When the silicon-steel collar with the guide sheath travels through the system, the magnetic flux is concentrated by the collar. Thus, the voltage outputs of the receiving electromagnets are changed. By analyzing the change of voltage outputs, the location of the silicon-steel collar with the guide sheath is obtained/targeted. This means that the location of the endo-bronchoscope is also targeted.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

Solar Filaments as Tracers of Subsurface Processes

2000 ◽  
Vol 179 ◽  
pp. 177-183
Author(s):  
D. M. Rust
Keyword(s):  
Magnetic Fields ◽  
Magnetic Flux ◽  
Coronal Mass Ejections ◽  
Interplanetary Space ◽  
Intermediate Stage ◽  
Coronal Plasma ◽  
Magnetic Helicity ◽  
The Sun ◽  
New Paradigm ◽  
Solar Filaments

AbstractSolar filaments are discussed in terms of two contrasting paradigms. The standard paradigm is that filaments are formed by condensation of coronal plasma into magnetic fields that are twisted or dimpled as a consequence of motions of the fields’ sources in the photosphere. According to a new paradigm, filaments form in rising, twisted flux ropes and are a necessary intermediate stage in the transfer to interplanetary space of dynamo-generated magnetic flux. It is argued that the accumulation of magnetic helicity in filaments and their coronal surroundings leads to filament eruptions and coronal mass ejections. These ejections relieve the Sun of the flux generated by the dynamo and make way for the flux of the next cycle.

Sunspot Groups as Tracers of Sub-Surface Processes

2000 ◽  
Vol 179 ◽  
pp. 155-160
Author(s):  
M. H. Gokhale
Keyword(s):  
Magnetic Flux ◽  
Indian Institute ◽  
Surface Processes ◽  
The Sun ◽  
Global And Local ◽  
Sunspot Groups

AbstractData on sunspot groups have been quite useful for obtaining clues to several processes on global and local scales within the sun which lead to emergence of toroidal magnetic flux above the sun’s surface. I present here a report on such studies carried out at Indian Institute of Astrophysics during the last decade or so.

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