Maximum Value Of Magnetic Field Research Articles

The effective of the inner radius of the iron free coil on the paraxial ray for magnetic lenses

In this paper, the magnetic flux density was studied using a mathematical model and different inner radius has been used for the iron free coil. The maximum value of magnetic field and the magnetic scalar potential was calculated. The paraxial ray can be studied using rung Kutta to solve the differential equation in the infinite and zero magnification condition, all results are determined using MATLAB program.

Stability and Convergence Analysis of a Biomagnetic Fluid Flow Over a Stretching Sheet in the Presence of a Magnetic Field

This investigated the time-dependent, two-dimensional biomagnetic fluid (blood) flow (BFD) over a stretching sheet under the action of a strong magnetic field. Blood is considered a homogeneous and Newtonian fluid, which behaves as an electrically conducting magnetic fluid that also exhibits magnetization. Thus, a full BFD formulation was considered by combining both the principles of magnetization and the Lorentz force, which arise in magnetohydrodynamics and ferrohydrodynamics. The non-linear governing equations were transformed by using the usual non-dimensional variables. The resulting system of partial differential equations was discretized by applying a basic explicit finite differences scheme. Moreover, the stability and convergence analysis were performed to obtain restrictions that were especially for the magnetic parameters, which are of crucial importance for this problem. The acquired results are shown graphically and were examined for several values of the dimensionless parameters. The flow and temperature distributions were increased as the values of the magnetic parameters were increased. With the progression in time, the flow profile and temperature distribution were also increased. It is hoped that the results of this problem will be used for high targeting efficiency toward determining the maximum values of magnetic field for which accurate flow predictions could be made using a very simple numerical scheme.

Magnetic and magnetocaloric properties in Cu-doped high Mn content Mn50Ni40−xCuxSn10 Heusler alloys

The effects of Cu substitution on the phase transitions and magnetocaloric effect of Mn50Ni40−xCuxSn10 Heusler alloys were investigated. With the increase of Cu content, the martensitic transformation (MT) temperature shifts substantially towards lower temperature, while the Curie temperature of austenite remains almost unchanged. The reverse MT temperature decreases from 180 to 171 K for Mn50Ni39Cu1Sn10 alloy as the magnetic field increases from 1 to 30 kOe. Under an applied magnetic field of 30 kOe, the maximum values of magnetic field induced entropy changes are 19.6, 28.9, and 14.2 J/kg K for x = 0, 1, and 2, respectively. The effective refrigerant capacities and hysteresis losses for these alloys were discussed in this paper.

The effect of combination of magnetic field and low temperature on doped quantum wells

In this work, we study in the optical absorption of lightly doped and compensated GaAs–GaAlAs quantum wells in the presence of applied magnetic field at low temperatures. The maximum values of magnetic field and temperature are chosen to be 10 T and 5 K , respectively. The wave functions and energies of electrons bound to impurities are calculated variationally using hydrogen-like functions. The absorption coefficient is computed through the use of Fermi golden rule and the statistics of this system is made by a self-consistent calculation of the electrostatic potential generated by ionized impurities, while the convergence parameter is the electronic chemical potential. We focus our attention on 1s→2p ± transitions. The results show that the range of frequency absorbed by the system stays unaltered in 1s→2p − transition and changes for the 1s→2p + transition, presenting a shift to higher frequencies as the magnetic field increases. Another important result is the decrease of the absorption coefficient for the lowest part of the frequency range as the temperature decreases, turning the material almost transparent for those frequencies. This kind of information may be useful for further diagnosis of quantum well systems.

Approximate Expressions for Maximum Values of Transient Magnetic Fields and Electromagnetic Forces Imposed on Windings in Superconducting Generators

AbstractAs superconducting generators have a number of advantages, the investigations for such machines have actively been carried out throughout the world.In the superconducting generator, it is very important to support the field winding and to protect it from quenching. On the other hand, since the armature winding is of air core, the evaluation of eddy current loss in the winding and the way it is supported arc inevitable. Thus, the magnetic fields and the electromagnetic forces acing on both the field and the armature windings at the early stages of the machine design should be known.In previous papers the transient behavior of magnetic fields and electromagnetic forces acting on the windings of a superconducting generator based on a computer simulation for a sudden 3‐phase fault have been discussed in part. However, the behavior of magnetic fields and electromagnetic forces during transient period is very complicated and many calculations are required to determine their maximum values.In this paper, for practical use at the early stages of the machine design, approximate expressions are derived to calculate the maximum values of the magnetic fields and electromagnetic forces on the windings in the case of a 3‐phase fault. To check these expressions numerically, a 1000‐MVA superconducting generator was conceptually designed. The numerical results obtained by using these expressions agree well with the computer simulation results.

Approximate Expressions of Maximum Values of Transient Magnetic Fields and Electromagnetic Forces Imposed on Windings in Superconducting Generator.

As superconducting generators have a number of advantages, the investigations for such machine have been actively carried out throughout the world.In the superconducting generator, it is very important to support the field winding and to protect it from quenching. On the other side, as the armature winding is of air core, the evaluation of eddy current loss in the winding and the way of its support are inevitable. Thus, we should know the magnetic fields and the electromagnetic forces acting on both the field and the armature windings at the early stages of the machine design.We have partially discussed in previous papers the transient behavior of magnetic fields and electromagnetic forces acting on the windings of a superconducting generator based on a computer simulation for a sudden 3-phase fault. However, the behavior of magnetic fields and electromagnetic forces during transient period is very complicated and many calculations are required in order to find their maximum values.In this paper, for practical use at the early stages of the machine design, we derived approximate expressions to calculate the maximum values of the magnetic fields and electromagnetic forces on the windings in the case of a 3-phase fault. In order to numerically check these expressions, we conceptually designed a 1, 000 MVA superconducting generator. The numerical results obtained by using these expressions agree well with the computer simulation results.