There is a great deal of interest in the use of nanostructured heterogeneous catalysts, particularly those based on expensive precious metals, in order to maximise the surface to volume ratio of the catalyst, potentially reducing the cost without sacrificing performance. When there is an abundance of reactants available, the effective reactivity will depend on the surface density of the catalyt...

The Lemaˆıtre and Schwarzschild analytical solutions for a relativistic spherical body of constant density are linked together through the use of the Weyl quadratic invariant. The critical radius for quasi-static gravita-tional collapse is shown to vary continuously from 9/8 of the Schwarzschild radius to the Schwarzschild radius itself while the internal pressures become locally anisotropic.

Aims. The dark matter content of early type galaxies (ETGs) is a hotly debated topic with contrasting results arguing in favour of or against the presence of significant dark mass within the effective radius and the change with luminosity and mass. To address this question, we investigate here the global mass to light ratio Υ(r) = M(r)/L(r) of a sample of 21 lenses observed within the Sloan Len...

The present paper deals with the dynamics of spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmological model a time varying constant $\Lambda$ where evolves cosmic (t) through Hubble parameter (H). We consider that has reflection symmetry $H \rightarrow -H $ $\Lambda(H)$ expressed in form Taylor series respect to H. Dynamical systems for three different cases based on possibilities...

The effective earth radius can transform the curved ray path into a straight line, and modified refractive index spherical ground plane. Using them simplify propagation modeling of electromagnetic waves in atmosphere, so they are widely used calculation long-range wave, adopted by ITU Recommendations IEEE Standards. In this paper, upon employing simple geometric methods, we provide general form...