We obtain using Schwinger’s proper time approach the Casimir-Euler-Heisenberg effective action of fermion fluctuations for the case of an applied magnetic field. We implement here the compactification of one space dimension into a circle through anti-periodic boundary condition. Aside of higher order non-linear field effects we identify a novel contribution to the vacuum permeability. These con...

The microstructure and magnetic properties i.e. the initial permeability, magnetic &ereffect and coercivity for the asquenched and annealed at different temperatures s C U I N ~ & ~ 5B9 samples are studied After annealing the samples at 573 K for 1 h the decrease of the initial permeability and increase of the disaccommodation amplitude are o b s e ~ e d These are connected with a local anisotr...

An analytical model for a composite material containing magnetic platelets is presented based on the modified asymmetric Bruggeman’s effective medium theory for permeability. The model takes into account crushing of bulk magnetic material and form factors of inclusions.

This paper deals with the theoretical investigation of the thermal instability of a thin layer of electrically conducting micropolar rotating fluid, heated from below in the presence of uniform vertical magnetic field in porous medium. A dispersion relation is obtained for a flat fluid layer, contained between two free boundaries using a linear stability analysis theory, and normal mode analysi...

The ultimate intrinsic signal-to-noise ratio is the highest possible signal-to-noise ratio, and the ultimate intrinsic specific absorption rate provides the lowest limit of the specific absorption rate for a given flip angle distribution. Analytic expressions for ultimate intrinsic signal-to-noise ratio and ultimate intrinsic specific absorption rate are obtained for arbitrary sample geometries...

The effect of confinement on the bosonic vacuum under the action of an applied magnetic field is computed using Schwinger's formalism for the effective action. The final result reproduces an effective La-grangian similar to the Heisenberg-Euler one in the limit of no confinement and in the case of confinement provides the necessary corrections to this Lagrangian at each order of magnitude of th...

When new composite optical materials are developed experimentally or studied in numerical simulations, it is essential to have a set of fundamental constraints that the optical constants of such materials must satisfy. In this paper I argue that positivity of the imaginary part of the magnetic permeability may not be one of such constraints, particularly in naturally occurring diamagnetics and ...

This study treats the optimised one-port (reflection coefficient) and two-port (shunt-through/series-through) measurement methods for complex permeability determination of solid soft magnetic materials using a vector network analyzer (VNA) at frequencies from 9 kHz to 6.5 GHz. The principle of measurement methods, the relationships of measured phasor voltage ratio (Sparameter) to complex impeda...

Two nondestructive electromagnetic/magnetic techniques including hysteresis loop and eddy current methodologies have been used to characterize microstructural changes of AISI D2 cold work tool steel as a result of quench and tempering treatments. To measure the fraction retained austenite in quenched microstructure, six specimens were austenitized in the range  of 1000-1130 °C. Samples austenit...