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"Intelligence Specialist (IS) is a US Navy enlisted rating within the Information Warfare community. The Intelligence Specialist rating was established in 1975 by combining the Photographic Intelligenceman (PT) rating (first established in 1957) and parts of the Yeoman (YN) rating. As of September 2018, there are roughly 2950 enlisted Intelligence Specialists in the US Navy. General description Military "intelligence" is a discipline utilized to collect information for decision makers within the military. Intelligence Specialists analyze information from all forms of intelligence (OSINT, HUMINT, SIGINT, etc) and interpret their value for decision makers. Intelligence Specialists present their information compiled through intelligence briefings and maps. Category:United States Navy ratings "
"Bay Park may refer to: * Bay Park, Michigan, an unincorporated community in Tuscola County * Bay Park, New York, a hamlet (and census-designated place) in Nassau County * Bay Park Square, a shopping mall in Ashwaubenon, Wisconsin "
"Helium II will "creep" along surfaces in order to find its own level - after a short while, the levels in the two containers will equalize. The Rollin film also covers the interior of the larger container; if it were not sealed, the helium II would creep out and escape. The liquid helium is in the superfluid phase. As long as it remains superfluid, it creeps up the inside wall of the cup as a thin film. It comes down on the outside, forming a drop which will fall into the liquid below. Another drop will form—and so on—until the cup is empty. A Rollin film, named after Bernard V. Rollin, is a 30 nm-thick liquid film of helium in the helium II state. It exhibits a "creeping" effect in response to surfaces extending past the film's level (wave propagation). Helium II can escape from any non-closed container via creeping toward and eventually evaporating from capillaries of 10−7 to 10−8 meters or greater. Rollin films are involved in the fountain effect where superfluid helium leaks out of a container in a fountain-like manner. They have high thermal conductivity. The ability of superfluid liquids to cross obstacles that lie at a higher level is often referred to as the Onnes effect, named after Heike Kamerlingh Onnes. The Onnes effect is enabled by the capillary forces dominating gravity and viscous forces. Waves propagating across a Rollin film are governed by the same equation as gravity waves in shallow water, but rather than gravity, the restoring force is the van der Waals force. The film suffers a change in chemical potential when the thickness varies. These waves are known as third sound. Thickness of the film The thickness of the film can be calculated by the energy balance. Consider a small fluid volume element \Delta V which is located at a height h from the free surface. The potential energy due to the gravitational force acting on the fluid element is \rho g h\Delta V, where \rho is the total density and g is the gravitational acceleration. The quantum kinetic energy per particle is \hbar^2/(2ml^2), where l is the thickness of the film and m is the mass of the particle. Therefore, the net kinetic energy is given by \hbar^2 f\rho \Delta V/(2m^2l^2), where f is the fraction of atoms which are Bose–Einstein condensate. Minimizing the total energy with respect to the thickness provides us the value of the thickness:Huang, K. (2017). A superfluid universe. World Scientific. .}} See also *Second sound References External links * Video of the property in action * Liquid Helium,Superfluid: demonstrating Lambda point transition/viscosity paradox/two fluid model/fountain effect/Rollin film/second sound Category:Helium Category:Condensed matter physics Category:Fluid mechanics de:Rollin-Film "