Partial Dynamical Symmetry in a Fermionic Many-Body System

The concept of partial symmetry is introduced for an interacting fermion system. The associated Hamiltonians are shown to be closely related to a realistic nuclear quadrupole-quadrupole interaction. An application to $^{12}$C is presented.Comment: 4 pages, 2 figures, Proc. Int. Conf. "Bologna 2000 - Structure of the Nucleus at the Dawn of the Century", Bologna, Italy, May 29 - June 3, 200

Composite powerplant and shroud therefor Patent

Shrouded composite propulsion system configuratio

Integral coolant channels supply made by melt-out method

Melt-out method of constructing strong, pressure-tight fluid coolant channels for chambers is accomplished by cementing pins to the surface and by depositing a melt-out material on the surface followed by two layers of epoxy-resin impregnated glass fibers. The structure is heated to melt out the low-melting alloy

Attitude and propellant flow control system and method Patent

Attitude and propellant flow control system for liquid propellant rocket vehicle

Restrictions on the geometry of the periodic vorticity equation

We prove that several evolution equations arising as mathematical models for fluid motion cannot be realized as metric Euler equations on the Lie group of all smooth and orientation-preserving diffeomorphisms on the circle. These include the quasi-geostrophic model equation, the axisymmetric Euler flow in higher space dimensions, and De Gregorio's vorticity model equation.Comment: 14 pages, 1 tabl