In this work we consider Hermitian matrix valued functions of 3 (real) parameters, and are interested in generic coalescing points of eigenvalues, conical intersections. Unlike our previous works [7, 4], where we worked directly with the Hermitian problem and monitored variation of the geometric phase to detect conical intersections inside a sphere-like region, here we consider the following co...

We formulate conditions on the geometry of a non-expanding horizon ∆ which are sufficient for the space-time metric to coincide on ∆ with the Kerr metric. We introduce an invariant which can be used as a measure of how different the geometry of a given non-expanding horizon is from the geometry of the Kerr horizon. Directly, our results concern the space-time metric at ∆ at the zeroth and the f...

output characteristics of fuel cells are affected by a large number of parameters such as geometry, dimensions, construction materials and conditions of supplying fluids. in this paper a mathematical model followed by a two-dimensional numerical approach has been presented to study the fuel cell parametrically. effect of oxygen concentration at gas diffusion layer entrance, temperature and pres...