LES modelling of nitric oxide (NO) formation in a propane-air turbulent reacting flame

Large Eddy Simulation (LES) technique is applied to investigate the nitric oxide (NO) formation in the propane-air flame inside a cylindrical combustor. In LES a spatial filtering is applied to the governing equations to separate the flow field into large scale eddies and small scale eddies. The large scale eddies which carry most of the turbulent energy are resolved explicitly while the unresolved small scale eddies are modelled. A Smagorinsky model with model constant Cs = 0.1 as well as a dynamic model has been employed for modelling of the sub-grid scale eddies, while the nonpremixed combustion process is modelled through the conserved scalar approach with laminar flamelet model. In NO formation model, the extended Zeldovich (thermal) reaction mechanism is taken into account through a transport equation for NO mass fraction. The computational results are compared with those of the experimental results investigated by Nishida and Mukohara [1] in co-flowing turbulent flame

Twin bent functions and Clifford algebras

This paper examines a pair of bent functions on $\mathbb{Z}_2^{2m}$ and their relationship to a necessary condition for the existence of an automorphism of an edge-coloured graph whose colours are defined by the properties of a canonical basis for the real representation of the Clifford algebra $\mathbb{R}_{m,m}.$ Some other necessary conditions are also briefly examined.Comment: 11 pages. Preprint edited so that theorem numbers, etc. match those in the published book chapter. Final post-submission paragraph added to Section 6. in "Algebraic Design Theory and Hadamard Matrices: ADTHM, Lethbridge, Alberta, Canada, July 2014", Charles J. Colbourn (editor), pp. 189-199, 201

Reconstruction of Initial Beam Conditions at the Exit of the DARHT II Accelerator

We consider a technique to determine the initial beam conditions of the DARHT II Accelerator by measuring the beam size under three different magnetic transport settings. This may be time gated to resolve the parameters as a function of time within the 2000 nsec pulse. This technique leads to three equations in three unknowns with solution giving the accelerator exit beam radius, tilt and emittance. We find that systematic errors cancel and so are not a problem in unfolding the initial beam conditions. Random uncorrelated shot to shot errors can be managed by one of three strategies: 1) make the transport system optically de-magnifying; 2) average over many individual shots; or 3) make the random uncorrelated shot to shot errors sufficiently small. The high power of the DARHT II beam requires that the beam transport system leading to a radius measuring apparatus be optically magnifying. This means that the shot to shot random errors must either be made small (less than about 1%) or that we average each of the three beam radius determinations over many individual shots.Comment: 3 pages, 3 figures, LINAC2000 paper TUB1

Twenty Years of Experience With the University of Arkansas Planetarium

The Model A-1 Spitz planetarium was placed in operation at the University of Arkansas in 1954. It was moved to its present location in 1972 and has continued to have a much expanded use. More than 8,000 persons attended demonstrations between 1 August 1972 and 31 March 1974. Approximately one third of these were University students in classes and laboratories; the remaining two thirds were accounted for by school and other youth groups and the public demonstrations

Jasper Skulls and Memento Mori

The jasper skulls in this Curiosity Cabinet sit on the scale atop the touch-ables table. Jasper, a type of impure silica usually a reddish color, is commonly carved for small sculptures, as we see in the skulls. The reddish tones of both skulls match the overall tone of the cabinet nicely, as well as complimenting the rich medium blue of the walls. Thematically, skulls perfectly align with other objects in the cabinet. A ubiquitous theme of curiosity cabinets in the 16th and 17th century is the inevitability of death. Symbols of this notion in art work are known as Memento mori or vanitas. Memento mori is derived from Latin, and roughly translates to, “remember you will die.” Vanitas is a related term with similar meaning: all Earthly pursuits are feeble because they are temporary. (excerpt