Vibrations in Leaking Spherical Valves with Annular Seal

Harbor seal vibrissa morphology suppresses vortex-induced vibrations.

Harbor seals (Phoca vitulina) often live in dark and turbid waters, where their mystacial vibrissae, or whiskers, play an important role in orientation. Besides detecting and discriminating objects by direct touch, harbor seals use their whiskers to analyze water movements, for example those generated by prey fish or by conspecifics. Even the weak water movements left behind by objects that hav...

Harp seal heart valves being tested for human use.

Note: A low leakage liquid seal for micromachined gas valves.

We report a method for addressing gas leakage in micromachined valves. The valves used for evaluating the proposed concept utilize a silicon valve seat that is bonded to a glass substrate and actuated by a piezoelectric stack, all of which are assembled within a ceramic package. The sealing method uses the capillary forces of a liquid sealant on the valve seat to reduce gas leakage below measur...

Liquid Encapsulation in Parylene Microstructures Using Integrated Annular-Plate Stiction Valves

We report the design, fabrication and characterization of micromachined Parylene structures for self-sealing liquid encapsulation applications. Automatic sealing is enabled through the use of an integrated annular-plate stiction valve which greatly reduces device footprint over in-plane configurations. We achieve automatic wafer-level liquid entrapment without using adhesives or processing at e...

Asymptotic Formulas for Active and Reactive Mutual Power of Free Vibrations of a Clamped Annular Plate

Normalized mutual power of radiation, active and reactive, has been analyzed in this paper. The sound source is an annular plate, clamped to a planar, rigid and infinite baffle. The plate’s vibrations are axisymmetric and sinusoidal with respect to time. A Kirchhoff-Love’s model of a perfectly elastic plate has been used. First, the integral formulas for the mutual sound power have been present...