arXiv subjects

V. Swamy

Publications and source records attributed to V. Swamy.

2 recordsLinked to original sources

arXiv2009

Cotunnite-structured titanium dioxide: the hardest known oxide

Despite great technological importance and many investigations, a material with measured hardness comparable to that of diamond or cubic boron nitride has yet to be identified. Combined theoretical and experimental investigations led to the discovery of a new polymorph of titanium dioxide with titanium nine-coordinated to oxygen in the cotunnite (PbCl2) structure. Hardness measurements on the cotunnite-structured TiO2 synthesized at pressures above 60 GPa and temperatures above 1000 K reveal that this material is the hardest oxide yet discovered. Furthermore, it is one of the least compressible (with a measured bulk modulus of 431 GPa) and hardest (with a microhardness of 38 GPa) polycrystalline materials studied thus far.

cond-mat.mtrl-sci↗

arXiv1994

Detection of Computer Generated Gravitational Waves in Numerical Cosmologies

We propose to study the behavior of complicated numerical solutions to Einstein's equations for generic cosmologies by following the geodesic motion of a swarm of test particles. As an example, we consider a cylinder of test particles initially at rest in the plane symmetric Gowdy universe on $T^3 \times R$. For a circle of test particles in the symmetry plane, the geodesic equations predict evolution of the circle into distortions and rotations of an ellipse as well as motion perpendicular to the plane. The evolutionary sequence of ellipses depends on the initial position of the circle of particles. We display snapshots of the evolution of the cylinder.

gr-qc↗