An analysis i presented ofthe impedance presented by a thin cylindrical e astic shell to a pressure or normal stress as a function of the axial wavelength and the angular dependence of the forces. Results of computation are presented graphically. This information is then used to compute a measure of the sound transmitted through the shell immersed inair for various particular cases. The theory ...

Given a set P of n points in three dimensions, a cylindrical shell (or zone cylinder) is formed by two circular cylinders with the same axis such that all points of P are between the two cylinders. We prove that the number of cylindrical shells enclosing P passing through combinatorially different subsets of P has size Ω(n) and O(n) (the previously known bound was O(n)). As a consequence, the m...

Composite stiffened cylindrical shells are widely used as primary elements in aerospace structures. In the recent years, there has been a growing research interest in optimum design of composite stiffened cylindrical shell structures for stability under buckling load.  This paper focuses upon the development of an efficient optimization of ring-stringer stiffened cylindrical shell. The opti...

In this paper we present a generalized Cassie-Baxter equation to take into account the effect of drop pressure on the apparent contact angle θ(app). Also we determine the limiting pressure p(W) which causes the impalement transition to the Wenzel state and the pull-off pressure p(out) at which the drop detaches from the substrate. The calculations have been carried out for axial-symmetric pilla...

The Gallium Nitride (GaN) Light-Emitting-Diode (LED) bottom refection grating simulation and results are presented. A microstructure GaN bottom grating, either conical holes or cylindrical holes, was calculated and compared with the non-grating (flat) case. A time monitor was also placed just above the top of the LED to measure both time and power output from the top of the LED. Many different ...

Diffusion-shaped film holes with compound angles are currently being investigated for high temperature gas turbine airfoil film cooling. An accurate prediction of the coolant blowing rate through these film holes is essential in determining the film effectiveness. Therefore, the discharge coefficients associated with these film holes for a range of hole pressure ratios is essential in designing...

Existence of nontrivial nonnegative equilibrium solutions for age structured population models with nonlinear diffusion is investigated. Introducing a parameter measuring the intensity of the fertility, global bifurcation is shown of a branch of positive equilibrium solutions emanating from the trivial equilibrium. Moreover, for the parameter-independent model we establish existence of positive...