Expressions For Field Intensity Research Articles

Radiation of sound in a semi-infinite hard duct inserted axially into a larger infinite lined duct

This article examines sound radiation from a hard semi-infinite duct placed symmetrically inside an acoustically lined duct. We introduce a wake on right handed region of the duct configuration to analyze sound radiation process for the trailing edge situation. The integral transforms together with Wiener–Hopf techniques render the solution of underlying problem. However expressions for field intensity involve infinite sums/products that enable solution using truncation approach. The sound radiation analysis is then observed graphically while using different choice of some pertinent parameters. It is worth mentioning that results of leading edge situation can be recovered as a limiting case.

Magnetic Fields of Twistors Represented by Confocal Hollow Prolate Spheroids

A twistor is an anisotropic ferromagnetic cylindrical wire with nonmagnetic core. The intrinsic magnetization flux curls in helical sense in the wire and has an air return path. Many field problems must be solved for their successful use as information storage elements. For instance, the demagnetizing field in the wire causes instability of storage and therefore must be reduced by suitable geometry of the twistor. The flux lines emanating from a bit link neighboring windings and also impose a magnetic field intensity in neighboring bits. The interactions, although undesirable in packing bits in a memory array, can be used to advantage as operating forces in logical devices.1 This paper analyzes the demagnetizing field in a twistor bit, based on the geometrical model of a confocal hollow prolate spheroid and the magnetic characterization of the material by B = μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (H+M) where M is the intrinsic magnetization, constant in magnitude, but oriented by the external field. Demagnetizing factors for confocal hollow prolate spheroids are plotted against length-to-diameter ratio and wall thickness. Expressions for field intensities outside a twistor bit are given. Analogies between twistors and thin films are examined.