Abstract: Considering a scenario where our universe is taken
as a 3d domain wall embedded in a 5d dimensional Minkowski
space-time, we explore the existence of a richer class of solitonic
solutions and their consequences for accelerating universes driven by
collisions of bulk particle excitations with the walls. In particular it
is shown that some of these solutions should play a fundamental role
at the beginning of the expansion process. We present some of these
solutions in cosmological scenarios that can be applied to models
that describe the inflationary period of the Universe.
Abstract: Reinforced concrete stair slabs with mid landings i.e.
Dog-legged shaped are conventionally designed as per specifications
of standard codes of practices which guide about the effective span
according to the varying support conditions. Presently, the behavior
of such slabs has been investigated using Finite Element method. A
single flight stair slab with landings on both sides and supported at
ends on wall, and a multi flight stair slab with landings and six
different support arrangements have been analyzed. The results
obtained for stresses, strains and deflections are used to describe the
behavior of such stair slabs, including locations of critical moments
and deflections. Values of critical moments obtained by F.E. analysis
have also have been compared with that obtained from conventional
analysis. Analytical results show that the moments are also critical
near the kinks i.e. junction of mid-landing and inclined waist slab.
This change in the behavior of dog-legged stair slab may be due to
continuity of the material in transverse direction in two landings
adjoining the waist slab, hence additional stiffness achieved. This
change in the behavior is generally not taken care of in conventional
method of design.