Application of quasi-homogeneous anisotropic laminates in grid-stiffened panel design

Composite laminates are derived for standard configurations with quasi-homogeneous anisotropic properties, whereby in-plane and out-of-plane stiffness properties are concomitant. Dimensionless parameters, and their relationship to the well-known ply- orientation-dependent lamination parameters, are also developed from which the elements of the extensional and bending stiffness matrices are readily calculated for any fiber/resin properties. The definitive list of laminate configurations for up to 21 plies is presented, together with graphical representations of the lamination parameter design space for standard ply orientations +45, -45, 0 and 90 degrees. Finally, the potential of quasi-homogeneous anisotropic laminates as an optimum design solution for anisogid structures is explored for cases where buckling and strength constraints are both active

Extension-twist coupled laminates for aero-elastic compliant blade design

A definite list of laminate configurations with extension-twisting (and shearing-bending) coupling is derived for up to 21 plies of identical thickness. The list comprises individual stacking sequences, containing standard angle-ply and cross-ply sub-sequences; combinations which are contrary to the previously assumed form for this class of laminate. The list also contains dimensionless parameters from which the extensional, coupling and bending stiffness terms are readily calculated for any fiber/matrix system. Lamination parameters are shown graphically to illustrate the extent of the design space with up to 21 plies. A special sub-group from this class of coupled laminate is identified that can be manufactured flat under a standard elevated temperature curing process; this sub-group possesses hygro-thermally curvature-stable behavior. Finally, bounds on the compression buckling strength are assessed using a closed form solution for all the laminate groups presented

Long-distance contributions to the QCD pressure

The QCD pressure is a most fundamental quantity, for which lattice data is available up to a few times the critical temperature $T_c$. Perturbation theory, even at very high temperatures, has serious convergence problems. Combining analytical and 3d numerical methods, we show that it is possible to compute the QCD pressure from about $2 T_c$ to infinity. We also describe an algorithm to generate and classify high order Feynman diagrams which is tailored to minimize computational effort.Comment: 5 pages; talk at Statistical QCD, Bielefeld, August 26-30, 200

Weak-coupling expansion of the hot QCD pressure

We review recent progress made in determining the pressure of hot QCD up to the first non-perturbative term in its weak-coupling expansion.Comment: 11 pg, Talk given at 29th Johns Hopkins Workshop in Theoretical Physics: Strong Matter in the Heavens, Budapest, Hungary, 1-3 Aug 200

The Magic Mirror - The Fashionista's world-view (and the rest of humanity's)

In this lecture, LCF Visiting Professor Peter York, author, journalist and broadcaster, looks at the contrasting attitudes to fashion amongst: 'fashionistas' (i.e. fashion professionals - but particularly high-end fashion journalists), and the rest of humankind. He argues that 'fashionistas' are - most of them - "quite astonishingly different" from the rest of humankind. This is a function of: * their 'expert' role * their place in the fashion market process * their milieu * their 'wardrobe opportunities' * their aesthetic education. 'Fashionistas', quite literally, see the world differently and talk about clothes differently. This means their reporting of fashion brings different criteria to bear, most of which are unacknowledged. Key differences are: * (at least while they're working) fashionistas develop the tastes of extremely rich women, and are enabled to satisfy them * fashionista language develops its own codes, distorting the meanings of familiar words (e.g. 'sexy') and introducing others (e.g. 'directional'), which only work in fashionland. * a total inability to acknowledge the role of age, class, the workplace or any other real world factors in real women's fashion options. The rest of humanity (broadly women readers of fashion coverage) have lives. These lives, situations and finances shape their views of fashion and their choices. Their concerns and language are wonderfully different from those of most 'fashionistas'. The misunderstandings between these contrasting world-views are richly comic and deeply sad

The Initial Value Problem Using Metric and Extrinsic Curvature

The initial value problem is introduced after a thorough review of the essential geometry. The initial value equations are put into elliptic form using both conformal transformations and a treatment of the extrinsic curvature introduced recently. This use of the metric and the extrinsic curvature is manifestly equivalent to the author's conformal thin sandwich formulation. Therefore, the reformulation of the constraints as an elliptic system by use of conformal techniques is complete.Comment: 10 pages, to appear in the Proceedings of the Tenth Marcel Grossmann Meeting on General Relativit

Influence of bending–twisting coupling on compression and shear buckling strength [Keynote]

No abstract available

Fragmentation of cosmic-string loops

The fragmentation of cosmic string loops is discussed, and the results of a simulation of this process are presented. The simulation can evolve any of a large class of loops essentially exactly, including allowing fragments that collide to join together. Such reconnection enhances the production of small fragments, but not drastically. With or without reconnections, the fragmentation process produces a collection of nonself-intersecting loops whose typical length is on the order of the persistence length of the initial loop