Discussion: “Stability of Shallow Arches Against Snap-Through Under Timewise Step Loads” (Hsu, C. S., 1968, ASME J. Appl. Mech., 35, pp. 31–39)

Symmetry breaking, snap-through and pull-in instabilities under dynamic loading of microelectromechanical shallow arches

Arch-shaped microelectromechanical systems (MEMS) have been used as mechanical memories, micro-relays, micro-valves, optical switches and digital micro-mirrors. A bi-stable structure, such as an arch, is characterized by a multivalued load deflection curve. Here we study the symmetry breaking, the snap-through instability and the pull-in instability of a bi-stable arch-shaped MEMS under static ...

J. Gen. Appl. Microbiol., 52, 29–35 (2006)

Some fatty acids (FAs) can inhibit or stimulate the growth of bacteria. In general, polyunsaturated FAs such as linoleic and linolenic acids have more inhibitory effects on bacteria than saturated and monounsaturated FAs (Nieman, 1954; Raychowdhury et al., 1985). Gram-positive bacteria, especially, are more sensitive to polyunsaturated FAs than Gram-negative bacteria (Greenway and Dyke, 1979). ...

J. Gen. Appl. Microbiol., 48, 35–41 (2002)

A river-ecosystem is strongly affected by human activities. The pollutants discharged into a river from human activities may destroy the ecosystem of the river. Microorganisms in rivers (including suspended and sessile microorganisms) play key roles in degrading the pollutant and therefore in preventing the river ecosystem from being destroyed. To establish suitable measures for the protection ...

Optimization of Shallow Arches against Instability Using Sensitivity Derivatives +

In this paper the author discusses the problem of optimization of shallow frame structures which involve a coupling of axial and bending responses. A shallow arch of a given shape and of given weight is optimized such that its limit point load is maximized. The cross-sectional area, A(x) and the moment of inertia, I(x) of the arch obey the relationship I(x) = p [A(x)] n, n = 1,2,3 and p is a sp...

J . Fluid Mech . 1 Numerical study of three - dimensional overturning waves in shallow water