Variational calculation of many-body wave functions and energies from density-functional theory

A generating coordinate is introduced into the exchange-correlation functional of density-functional theory (DFT). The many-body wave function is represented as a superposition of Kohn-Sham (KS) Slater determinants arising from different values of the generating coordinate. This superposition is used to variationally calculate many-body energies and wave functions from solutions of the KS equation of DFT. The method works for ground and excited states, and does not depend on identifying the KS orbitals and energies with physical ones. Numerical application to the Helium isoelectronic series illustrates the method's viability and potential.Comment: 4 pages, 2 tables, J. Chem. Phys., accepte

Ultrasonic scanner for radial and flat panels

An ultrasonic scanning mechanism is described that scans panels of honeycomb construction or with welded seams. It incorporates a device which by simple adjustment is adapted to scan either a flat panel or a radial panel. The supporting structure takes the form of a pair of spaced rails. An immersion tank is positioned between the rails and below their level. A work holder is mounted in the tank and is adapted to hold the flat or radial panel. A traveling bridge is movable along the rails and a carriage is mounted on the bridge

On Superalgebras of Matrices with Symmetry Properties

It is known that semi-magic square matrices form a 2-graded algebra or superalgebra with the even and odd subspaces under centre-point reflection symmetry as the two components. We show that other symmetries which have been studied for square matrices give rise to similar superalgebra structures, pointing to novel symmetry types in their complementary parts. In particular, this provides a unifying framework for the composite `most perfect square' symmetry and the related class of `reversible squares'; moreover, the semi-magic square algebra is identified as part of a 2-gradation of the general square matrix algebra. We derive explicit representation formulae for matrices of all symmetry types considered, which can be used to construct all such matrices.Comment: 25 page

Development of ductile claddings for dispersion-strengthened nickel-base alloys Final report

Development of ductile oxidation-resistant cladding alloys for thoria dispersion, strengthened nickel and nickel-chromiu

The Complete Jamming Landscape of Confined Hard Discs

An exact description of the complete jamming landscape is developed for a system of hard discs of diameter $\sigma$, confined between two lines separated by a distance $1+\sqrt{3/4} < H/\sigma < 2$. By considering all possible local packing arrangements, the generalized ensemble partition function of jammed states is obtained using the transfer matrix method, which allows us to calculate the configurational entropy and the equation of state for the packings. Exploring the relationship between structural order and packing density, we find that the geometric frustration between local packing environments plays an important role in determining the density distribution of jammed states and that structural "randomness" is a non-monotonic function of packing density. Molecular dynamics simulations show that the properties of the equilibrium liquid are closely related to those of the landscape.Comment: 5 Pages, 4 figure

Interacting with digital media at home via a second screen

In recent years Interactive Television (iTV) has become a household technology on a global scale. However, iTV is still a new technology in the early stages of its evolution. Our previous research looked at how everyday users of iTV feel about the interactive part of iTV. In a series of studies we investigated how people use iTV services; their likes, dislikes, preferences and opinions. We then developed a second screen-based prototype device in response to these findings and tested it with iTV users in their own homes. This is a work in progress paper that outlines the work carried previously in the area of controlling interactive Television via a second screen. The positive user responses led us to extend the scope of our previous research to look into other related areas such as barriers to digital interactive media and personalisation of digital interactive media at home

Dynamics of axial separation in long rotating drums

We propose a continuum description for the axial separation of granular materials in a long rotating drum. The model, operating with two local variables, concentration difference and the dynamic angle of repose, describes both initial transient traveling wave dynamics and long-term segregation of the binary mixture. Segregation proceeds through ultra-slow logarithmic coarsening.Comment: 4 pages, 3 Postscript figures; submitted to PR