By using BPS closed string, the entropy is calculated of the extremal five dimensional black hole consisting of Dirichlet onebranes, Dirichlet fivebranes and Kaluza-Klein momentum in the flat background approximation. In our formulations we consider two kinds of BPS closed strings with or without a winding number. In the former case heavy excitation modes of closed strings are used to derive th...

Transformer tank vibration has been used for the condition monitoring and fault diagnosis of power transformers, as well as for the evaluation of radiated sound power from such power transformers. In both applications, seeking a correlation between transformer tank vibration and the vibration of the transformer windings and core becomes a challenge for fault identification and noise control at ...

We investigate the mechanism by which topological defects form in first order phase transitions with a charged order parameter. We show how thick superconductor vortices and heavy cosmic strings form by trapping of magnetic flux. In an external magnetic field, intermediate objects such as strips and membranes of magnetic flux and chains of single winding defects are produced. At non-zero temper...

Fiber winding tension is an important factor in the molding techniques of composite material which influences the quality of winding product directly, and the tension control is a key technique in fiber winding techniques. This paper introduces a closed-loop tension control system with the programmable logic controller (PLC) with function modules as its control kernel, the alternating current (...

This paper presents a comparative study of two types of wound field three-phase switched-flux machine (SFM) with non-overlap winding and salient rotor. Both armature and field winding are located on the stator and rotor is composed of only stack of iron. Non-overlap armature and field windings and toothed-rotor are the clear advantages of these machines as the copper losses gets reduce and roto...

The strong correlation between the level of eddy current losses and the winding geometry shows all the necessity of special attention to the manner of disposition of coils in machine slots and to the wire type whether it’s solid or stranded conductor. Since the transposition of winding strands is a recommended solution to reduce eddy current losses, this article suggests an electromagnetic anal...

A six-level inverter system for an open-end winding induction motor drive is presented in this paper. Multilevel inversion is achieved by feeding an open-end winding induction motor with a 3-level inverter from one end and a 2-level inverter from the other end of the motor. The 3level inverter used in the proposed drive, is realized by cascading two 2-level inverters. The combined inverter syst...

We consider a family of four-dimensional non-linear sigma models based on an O(5) symmetric group, whose fields take their values on the 4-sphere S4. An SO(4)-subgroup of the model is gauged. The solutions of the model are characterised by two distinct topological charges, the Chern-Pontryagin charge of the gauge field and the degree of the map, i.e. the winding number, of the S4 field. The one...

T he size, performance and cost of a power electronic system are closely linked to the like parameters of the magnetic components. Since custom power transformers are widely used, transformer design is a frequent design process that has a signifi cant impact on system performance. Yet most high-frequency transformers use less than 25% of the available core window for effi cient current conducti...

In the standard R4 embedding of the chiral O(4) model in 3+1 dimensions the winding number is not conserved near the chiral phase transition and thus no longer can be identified with baryon number. In order to reestablish conserved baryon number in effective low-energy models near and above the critical temperature Tc it is argued that insisting in O(N) models on the angular nature of the chira...