Precise toppling balance, quenched disorder, and universality for sandpiles

A single sandpile model with quenched random toppling matrices captures the crucial features of different models of self-organized criticality. With symmetric matrices avalanche statistics falls in the multiscaling Bak-Tang-Wiesenfeld universality class. In the asymmetric case the simple scaling of the Manna model is observed. The presence or absence of a precise toppling balance between the amount of sand released by a toppling site and the total quantity the same site receives when all its neighbors topple once determines the appropriate universality class.     

Solitons in a relativistic plasma with negative ions

The interaction of the nonlinearity and the dispersiveness causing the solitary waves is studied in a relativistic plasma with negative ions through the derivation of a nonlinear partial-differential equation known as the Korteweg-de Vries equation. The negative ions play a salient part in the existence and behavior of the solitons and could be of interest in laboratory plasmas. First, the observations are made in a nonisothermal plasma, and later the reduction to the nonisothermality of the plasma shows entirely different characteristics as compared to the solitons in the isothermal plasmas. Comparison with the various solitons is emphasized     

Non-linear dynamic behaviour of plates on elastic foundations

The large amplitude transverse vibration characteristics of a simply-supported isotropic equilateral triangular plate on elastic foundation have been investigated by following Berger's well-known approximate method in conjunction with a special type of co-ordinates known as tri-linear co-ordinates. A second order non-linear differential equation for the unknown time function has been obtained and solved, as usual, in terms of Jacobian elliptic functions. Results obtained from numerical calculations are presented graphically.     

Magnetization curves for general cylindrical samples in a transverse field

Using the recent results for the surface current density on cylindrical surfaces of arbitrary cross-section producing uniform interior magnetic field we propose a method for obtaining solutions of Bean’s critical state model for general cylindrical samples. The method uses the technique of conformal mapping to express the sample surface and the flux-fronts in terms of a set of coefficients that depend on a parameter. The flux-fronts are to be determined by solving a system of nonlinear ordinary differential equations for the coefficients. Retaining only a certain finite number of leading coefficients we get an approximate solution. The procedure is illustrated by considering two cyclindrical samples — one with an elliptical cross-section and the other with a non-elliptical cross-section. The virgin curve and small and large magnetization hysteresis loops for the two samples are obtained.     

Study of electrically small printed chakra (wheel) antenna

A novel printed antenna configuration in the form of a chakra (wheel) is presented. The antenna has many design parameters, such as axle radius, rim radius, and shaft location, and exhibits a very low design frequency which is five times smaller than that of a regular circular microstrip patch antenna of the same size     

Application of quantum dot gate nonvolatile memory (QDNVM) in image segmentation

This paper presents the application of quantum dot gate nonvolatile memory (QDNVM) in image processing application. The charge accumulation in the gate region varies the threshold voltage of QDNVM, which can be used as a reference voltage source in a comparator circuit. A simplified comparator circuit can be implemented using the QDNVM. In this work, the use of QDNVM-based comparators in image processing specially image segmentation is demonstrated, which can be efficient in future image processing application.