Phase delay time and superluminal propagation in barrier tunneling

In this work we study the behaviour of Wigner phase delay time for tunneling in the reflection mode. Our system consists of a circular loop connected to a single wire of semi-infinite length in the presence of Aharonov-Bohm flux. We calculate the analytical expression for the saturated delay time. This saturated delay time is independent of Aharonov- Bohm flux and the width of the opaque barrier thereby generalizing the Hartman effect. This effect implies superluminal group velocities as a consequence. We also briefly discuss the concept called "space collapse or space destroyer".Comment: 5 pages, 5 figure

Stochastic thermodynamics of macrospins with fluctuating amplitude and direction

We consider stochastic energy balance and entropy production (EP) in a generalized Langevin dynamics of macrospins, allowing for both amplitude and direction fluctuations, under external magnetic field. EP is calculated using Fokker-Planck equation, distinguishing between reversible and irreversible parts of probability currents. The system entropy increases due to irreversible non-equilibrium processes, and reduces as heat dissipates to surrounding environment. Using path probability distributions of time-forward trajectories and conjugate trajectories under time reversal, we obtain fluctuation theorems (FT) for total stochastic EP. We show that the choice of conjugate trajectories is crucial in obtaining entropy like quantities that obey FTs.Comment: 7 pages, no figure; version accepted for publication in Phys. Rev.

Environmental Issues in Metal Extraction

The non-ferrous metals industry is a key sector in the Indian economy as it meets the requirements of a wide range of key industries including engineering, electrical and electronics, infrastructure, automobile and automobile components, packaging etc. The Indian non-ferrous metals industry comprises of the primary and secondary downstream seginents. Primary producers are those players who process the mined ore to obtain the primary metal. This metal is commercially available in the form of rods, ingots, cath-odes, wires etc., Secondary producers are those players who manufacture value added products like foils, extrus-ions, dry batteries, castings etc., either by procuring the metal from the primary producers or from scrap

Multi-gravity Separator An Equipment for Separation of Fines

Multi-gravity seperator, more popularly known as MGS,burst into the mineral dressing scene around the mid eighties. Since then it has found acceptance in a wide variety of applications. It has replaced column cells for fine cass-eterite recovery in Wheal Jane in the UK and has been found to be the only equipment which could satisfactorily remove graphite front lead concentrate in Hindustan Zinc mines. MGS has found application in Tantalum recovery as also for upgrading Graphite concentrate. The capability of the machine to recover very fine particles (upto 2-3 micron) and produce a clean concentrate has made it a favoured equipment over a wide range of specific gravities. This paper deals with the details of the constructional features and operational aspects of Multi gravity sepe-rator Live cases have been discussed

Environmental Issues in the Processing and Extraction of Non-ferrous Metals

The non-ferrous metals industry is a key sector in the Indian economy as it meets the requirements of a wide range of key industries including engineering, electrical and electronics, infrastructure, automobile and automobile components, packaging etc. The Indian non-ferrous metals industry comprises of the primary and secondary downstream segments. Primary producers are those players who process the mined ore to obtain the primary metal. This metal is commercially available in the form of rods, ingots, cathodes, wires etc., Secondary producers are those players who manufacture value added products like foils, extrus-ions, dry batteries, castings etc., either by procuring the metal from the primary producers or from scrap

Clean Technologies in Nonferrous Metals Recycling

The importance of metal recycling is highlighted. A brief overview of technology used in the recycling of common nonferrous metals such as aluminium, lead, zinc and copper is presented. Both traditionally used processes and clean technology options that has emerged in the recent past or are in the development stage are discussed

Application of semi-implicit scheme of integration to barotropic prediction

Application of a semi-implicit version of primitive equation barotropic model to predict monsoon depressions is proposed. Forecasts upto 48 hr have been quite satisfactory. The results are compared with those obtained from an explicit version of primitive equation barotropic model developed earlier. The flow patterns from these two versions are similar with few exceptions in isolated pockets, however, the forecast movement obtained from the semi-implicit version is comparable or slightly superior to those obtained from the explicit version. The computational time in semi-implicit and explicit schemes is approximately in the ratio of 1:2

Phase dealy time and superluminal propagation in barrier tunneling

In this work we study the behaviour of Wigner phase delay time for tunneling in the reflection mode. Our system consists of a circular loop connected to a single wire of semi-infinite length in the presence of Aharonov-Bohm flux. We calculate the analytical expression for the saturated delay time. This saturated delay time is independent of Aharonov- Bohm flux and the width of the opaque barrier thereby generalizing the Hartman effect. This effect implies superluminal group velocities as a consequence. We also briefly discuss the concept called "space collapse or space destroyer"