Bianchi Type I Magnetized Cosmological Model in Bimetric Theory of Gravitation

In this paper, we attempt to construct a Bianchi Type I magnetized cosmological model in Rosen’s bimetric theory of gravitation by using the techniques of Letelier and Stachel under the condition that ABCn , where n 0 in Rosen’s field equations. The physical and geometrical significance of the model are discussed. It is important to note the added dimension of this paper include the introduction of a magnetic field on the model. Prior to this, all it has been is a vacuum model in bimetric gravitation

Bianchi Type I Bulk Viscous Fluid String Dust Cosmological Model with Magnetic Field in Bimetric Theory of Gravitation

In the presence of both magnetic field and bulk viscosity, Bianchi Type I bulk viscous fluid string dust cosmological model in Rosen’s bimetric theory of gravitation have been investigated by using the technique of Letelier and Stachel. The nature of the model is discussed in the absence of both magnetic field and bulk viscosity. To get a determinate solution, we have assumed the condition that σ is proportional to θ and ζθ = constant where σ is the shear, θ is the expansion in the model and ζ is the coefficient of bulk viscosity. Further the physical and geometrical significance of the model are discussed. Here, we compared between the case in the presence of magnetic field and bulk viscosity and the case in the absence of magnetic field and bulk viscosity

LRS Bianchi Type-II Cosmological Model with String Bulk Viscous Fluid and Magnetic Field in Barber’s Second Self Creation Theory

We present a solution of LRS Bianchi type-II space-time with string viscous fluid and magnetic field by solving the Barber’s field equations of self-creation theory of gravitation and it is seen that Barber scalar function affects the other physical parameters of the model and contributes a very high matter density, with high particle density at early stage of the universe and also it contributes the negative role of bulk viscous fluid in the evolution. Other geometrical and physical aspects of the model are also studied

Bianchi Type-I Hyperbolic Models with Perfect Fluid and Dark Energy in Bimetric Theory of Gravitation

Three different Bianchi type-I cosmological models as related to perfect fluid, with quintessence and with Chaplygin gas, in bimetric theory of gravitation have been deduced. The perfect fluid model has hyperbolic geometry and all its physical parameters are also hyperbolic in nature and therefore they have been studied from hyperbolic geometric view point. All these models are isotropize and shear-less. Other geometrical and physical behaviors of the models have also been studied. The hyperbolic geometric view point of the models will be helpful to the people who use observational data to search for such type of geometry

Anomalous change in leakage and displacement currents after electrical poling on lead-free ferroelectric ceramics

We report the polarization, displacement current and leakage current behavior of a trivalent nonpolar cation Al cation substituted lead free ferroelectric NBT-BT electroceramics with tetragonal phase and P4mm space group symmetry. Nearly three orders of magnitude decrease in leakage current were observed under electrical poling, which significantly improves microstructure, polarization, and displacement current. Effective poling neutralizes the domain pinning, traps charges at grain boundaries and fills oxygen vacancies with free charge carriers in matrix, thus saturated macroscopic polarization in contrast to that in upoled samples. E-poling changes bananas type polarization loops to real ferroelectric loops.Comment: 18 pages, 5 figure

EOAODV: Routing Protocol for Cognitive Radio Network

Cognitive Radio (CR) technology provides promising and a new solution to improve the spectrum utilization. In recent years, cognitive radio technology (CR) has been proposed to allow unlicensed secondary users (SUs) to opportunistically access the channels unused by primary users (PU). This paper focuses on designing Enhancement of Opportunistic Ad-hoc On Demand Distance Vector (EOAODV) routing protocol that uses shortest distance, Expected Transmissions Count (ETC) and residual energy as a parameter to select the most reliable link and the next forwarding node. The selection of route in the network by the traditional AODV is based on hop count. It is proposed to achieve a gain of Opportunistic Routing (OR) with AODV for cognitive radio wireless sensor networks (CRWSN) to improve its efficiency. In the OR work the nexthop node selection was based on only Expected Transmission Count (ETC). In this case if the same node is selected as nexthop for many times, energy of that node is drained and node may be dead. To overcome this problem, a technique is contributed that is energy based nexthop selection ie. EOAODV. The ETC is computed based on the quantized value of RSSI of the links with residue energy in the forwarding node. Using ETC the reliable link is computed and stored in routing table. The packets are tranmitted to the destination using channel details and the next hop, available in the routing table. The next hop selection is based on high energy in the nodes, shortest distance and least ETC