An investigation on the effects of Ag addition in the powder — in tube processing of long multifilamentary (Bi,Pb) - 2223/Ag superconducting tapes

It is important that long superconducting tape must have desired strain tolerance (less reduction of Jc with applied strains) and stress tolerance (less reduction of JC in applied stresses) for its use as coils and magnets. Ag addition to the BPSCCO system has many advantages with its physical and chemical inertness to the system, reduces the processing temperature, and promotes the grain growth, grain alignment and connectivity. All these not only enhance the critical current density of the tapes but also improve the mechanical properties. But the published results show very much scattering on the type of Ag additive to be selected, method of addition and its optimum percentage. Also there are some negative reports in this regard. The present work has been undertaken to study the effect of silver addition in different forms (Ag powder, Ag2O, AgNO3) on the superconducting and mechanical properties of (Bi,Pb)-2223/Ag tapes and to find out a suitable form of Ag additive and its optimum percentage to have better superconducting and mechanical properties. Also it is the aim of the present work is to optimise the process parameters needed to prepare (Bi,Pb)-2223/Ag multifilamentary tapes of length ~ 12 m in solenoid and pancake coil forms with good critical current density and homogeneity of J C along the length of the tapes.

A Realization Of An Fpga Sub System For Reducing Odometric Localization Errors In Wheeled Mobile Robots

This paper introduces a simple and efficient method and its implementation in an FPGA for reducing the odometric localization errors caused by over count readings of an optical encoder based odometric system in a mobile robot due to wheel-slippage and terrain irregularities. The detection and correction is based on redundant encoder measurements. The method suggested relies on the fact that the wheel slippage or terrain irregularities cause more count readings from the encoder than what corresponds to the actual distance travelled by the vehicle. The standard quadrature technique is used to obtain four counts in each encoder period. In this work a three-wheeled mobile robot vehicle with one driving-steering wheel and two-fixed rear wheels in-axis, fitted with incremental optical encoders is considered. The CORDIC algorithm has been used for the computation of sine and cosine terms in the update equations. The results presented demonstrate the effectiveness of the technique