The Navier-Stokes regularity problem

There is currently no proof guaranteeing that, given a smooth initial condition, the three-dimensional Navier–Stokes equations have a unique solution that exists for all positive times. This paper reviews the key rigorous results concerning the existence and uniqueness of solutions for this model. In particular, the link between the regularity of solutions and their uniqueness is highlighted

The Fog of War: Large-Scale Smoke Screening Operations of First Canadian Army in Northwest Europe

Smoke screens have been employed in sea and land warfare for many centuries for a variety of purposes. They have been used to conceal troop movements, to deceive the enemy as to combat strengths, point of attack, and preparations for offensive operations. During the Second World War all armies made use of smoke screns in their operations to a greater or lesser extent. Canada was no exception and was considered to be extremely innovative in the use of smoke equipment in ways for which it was not designed. The First Canadian Army first employed large-scale non-artillery-projected smoke screens during the campaign in Northwest Europe. For the first time, at least in the history of Canadian operations, units of trained specialists worked to lay down smoke screens in the field

Partially quenched QCD with a chemical potential

Using a chiral random matrix theory we can now derive the low energy partition functions and Dirac eigenvalue correlations of QCD with different chemical potentials for the dynamical and valence quarks. The results can also be extended to complex (and purely imaginary) chemical potential. We also discuss possible applications such as fitting to low energy constants and understanding the phase diagrams of the full and partially quenched theories.Comment: 7 pages, 9 figures, Lattice 2006 (High Temperature and Density

Compression Pylon

A compression pylon for an aircraft with a wing-mounted engine, that does not cause supersonic airflow to occur within the fuselage-wing-pylon-nacelle channel is presented. The chord length of the pylon is greater than the local chord length of the wing to which it is attached. The maximum thickness of the pylon occurs at a point corresponding to the local trailing edge of the wing. As a result, the airflow through the channel never reaches supersonic velocities