Understanding the tsunami with a simple model

In this paper, we use the approximation of shallow water waves (Margaritondo G 2005 Eur. J. Phys. 26 401) to understand the behaviour of a tsunami in a variable depth. We deduce the shallow water wave equation and the continuity equation that must be satisfied when a wave encounters a discontinuity in the sea depth. A short explanation about how the tsunami hit the west coast of India is given based on the refraction phenomenon. Our procedure also includes a simple numerical calculation suitable for undergraduate students in physics and engineering

Structural and magnetic aspects of the metal insulator transition in Ca2−x_{2-x}Srx_xRuO4_4

The phase diagram of Ca$_{2-x}$Sr$_x$RuO$_4$ has been studied by neutron diffraction on powder and single-crystalline samples. The experiments reveal antiferromagnetic order and structural distortions characterized by tilts and rotations of the RuO$_6$-octahedra. There is strong evidence that the structural details of the isovalent samples tune the magnetic as well as the electronic behavior. In particular we observe for low Sr-concentration a metal insulator transition associated with a structural change and magnetic ordering

Resonant nucleation of spatio-temporal order via parametric modal amplification

We investigate, analytically and numerically, the emergence of spatio-temporal order in nonequilibrium scalar field theories. The onset of order is triggered by destabilizing interactions (DIs), which instantaneously change the interacting potential from a single to a double-well, tunable to be either degenerate (SDW) or nondegenerate (ADW). For the SDW case, we observe the emergence of spatio-temporal coherent structures known as oscillons. We show that this emergence is initially synchronized, the result of parametric amplification of the relevant oscillon modes. We also discuss how these ordered structures act as bottlenecks for equipartition. For ADW potentials, we show how the same parametric amplification mechanism may trigger the rapid decay of a metastable state. For a range of temperatures, the decay rates associated with this resonant nucleation can be orders of magnitude larger than those computed by homogeneous nucleation, with time-scales given by a simple power law, $\tau_{\rm RN}\sim[E_b/k_BT]^B$, where $B$ depends weakly on the temperature and $E_b/k_BT$ is the free-energy barrier of a critical fluctuation.Comment: 38 pages, 20 figures now included within the tex

Uniaxial-Pressure induced Ferromagnetism of Enhanced Paramagnetic Sr3Ru2O7

We report a uniaxial pressure-dependence of magnetism in layered perovskite strontium ruthenate Sr3Ru2O7. By applying a relatively small uniaxial pressure, greater than 0.1 GPa normal to the RuO2 layer, ferromagnetic ordering manifests below 80 K from the enhanced-paramagnet. Magnetization at 1 kOe and 2 K becomes 100 times larger than that under ambient condition. Uniaxial pressure dependence of Curie temperature T_C suggests the first order magnetic transition. Origin of this uniaxial-pressure induced ferromagnetism is discussed in terms of the rotation of RuO6 octahedra within the RuO2 plane.Comment: 8 pages, 3 figures. to be published in Journal of the Physical Society of Japan, vol.73, No.5 (2004

COVID-19 pandemic:Nigerian University lecturers’ response to virtual orientation

The effect of the COVID-19 pandemic globally and the disruptions occasioned by it has far-reaching implications on societies in general and most especially the educational sector with governments across the globe ordering lockdowns including the closure of education institutions thereby necessitating alternative teaching and learning methods other than the usual face-to-face interaction to avoid a total collapse of the education sector. This study investigates Nigerian University lecturers’ perspective and response to virtual learning as an alternative to face-to-face teaching method during the pandemic. Relying on primary data source collected using questionnaires, a total number of 435 lecturers responded across both public and private universities and their responses analysed using SPSS. The study found that lecturers from private universities responded to virtual teaching than those from public universities; that the presence of infrastructural orientation influences virtual orientation; and that a negative relationship exists between the sociodemographic/occupational variables (gender, current position, years of experience) and virtual orientation of lecturers of Nigerian universities

Renormalization of the Inverse Square Potential

The quantum-mechanical D-dimensional inverse square potential is analyzed using field-theoretic renormalization techniques. A solution is presented for both the bound-state and scattering sectors of the theory using cutoff and dimensional regularization. In the renormalized version of the theory, there is a strong-coupling regime where quantum-mechanical breaking of scale symmetry takes place through dimensional transmutation, with the creation of a single bound state and of an energy-dependent s-wave scattering matrix element.Comment: 5 page