Experimental and numerical study on axial impact loading of pultruded composite tubes

The application of fibre reinforced composites has been increasing in the area of impact and blast loading of structures. The major advantages of these materials over metals are higher specific energy absorption, more economical, low weight and less maintenance. In this work, an attempt is made to study the energy absorption characteristics of unidirectional pultruded composite tubes. Two different cross sections (circular and square) were used for the study. To absorb more energy during the impact or blast loading the composite tubes have to deform progressively. To induce the progressive deformation of composite tubes two different types of triggering mechanisms were used. The energy absorption of each tube was studied experimentally. A new approach was adopted using cohesive elements for the numerical assessment of the energy absorbing capability of composite tubes. Finally the experimental and numerical results were compared

Quantum interference induced photon localisation and delocalisation in coupled cavities

We study photon localisation and delocalisation in a system of two nonlinear cavities with intensity-dependent coupling. It is shown that complete localisation or delocalisation is possible for proper choices of the strengths of nonlinearity, detuning and inter-cavity coupling. Role of the relative phase in the initial superposition in attaining localisation and delocalisation is discussed. Effects of dissipation and decoherence are considered and the use of quantum interference in reducing dissipation is explored. Many of the features of the system are shown to be the consequences of quantum interference.Comment: 18 pages, 10 figure

Nonadiabatic charge pumping across two superconductors connected through a normal metal region by periodically driven potentials

Periodically driven systems exhibit resonance when the difference between an excited state energy and the ground state energy is an integer multiple of $\hbar$ times the driving frequency. On the other hand, when a superconducting phase difference is maintained between two superconductors, subgap states appear which carry a Josephson current. A driven Josephson junction therefore opens up an interesting avenue where the excitations due to applied driving affect the current flowing from one superconductor to the other. Motivated by this, we study charge transport in a superconductor-normal metal-superconductor (SNS) junction where oscillating potentials are applied to the normal metal region. We find that for small amplitudes of the oscillating potential, driving at one site reverses the direction of current at the superconducting phase differences when difference between the subgap eigenenergies of the undriven Hamiltonian is integer multiple of $\hbar$ times the driving frequency. For larger amplitudes of oscillating potential, driving at one site exhibits richer features. We show that even when the two superconductors are maintained at same superconducting phase, a current can be driven by applying oscillating potentials to two sites in the normal metal differing by a phase. We find that when there is a nonzero Josephson current in the undriven system, the local peaks and valleys in current of the system driven with an amplitude of oscillating potential smaller than the superconducting gap indicates sharp excitations in the system. In the adiabatic limit, we find that charge transferred in one time period diverges as a powerlaw with pumping frequency when a Josephson current flows in the undriven system. Our calculations are exact and can be applied to finite systems. We discuss possible experimental setups where our predictions can be tested.Comment: 9 pages, 9 figures. Published versio

On the WW-algebra in the Calegero-Sutherland model using the Exchange operators

We study the $W_\infty$ algebra in the Calegero-Sutherland model using the exchange operators. The presence of all the sub-algebras of $W_\infty$ is shown in this model. A simplified proof for this algebra, in the symmetric ordered basics, is given. It is pointed out that the algebra contains in general, nonlinear terms. Possible connection to the nonlinear $W_\infty$ is discussed.Comment: Plain Tex, no figures, 13 page

Human Deprivation Index: A Measure of Multidimensional Poverty

Poverty is multidimensional in nature. Poverty is associated not only with insufficient income or consumption but also with insufficient outcomes with respect to health, nutrition, and literacy and deficient social relations, insecurity, and low self-esteem and powerlessness. Since poverty is a multidimensional phenomenon, measurement of poverty must cover many dimensions. So far, the income and/or consumption indicator has received most attention. But, now the focus is shifted towards deprivation in different dimensions for example income, health and education. The human development and human deprivation studies have opened new perspectives on measuring and analysing poverty and development with the help of multidimensional concept. The present study, in this context will serve to enrich useful knowledge about human deprivation which analysis the poverty multi dimensionally.Human Deprivation; Poverty; Multi dimension; Health; Infant Mortality; Education; Illiteracy; India