525 research outputs found

    Restoring Prosperity: The State Role in Revitalizing America's Older Industrial Cities

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    Presents a five-part agenda and organizing plan to reinvigorate the nation's older industrial cities, and aims to mobilize governors, legislative leaders, and local constituencies toward advancing urban reform

    A force balance system for the measurement of skin friction drag force in the presence of large vibrations and temperatures

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    Design of counterbalance system for skin friction drag measurements on hypersonic vehicle

    Multi-component Force Balance Control Systems Final Report

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    Technique and apparatus for drag, lift, and pitch force measurements in hypersonic wind tunnel

    Cohomology of groups of diffeomorphims related to the modules of differential operators on a smooth manifold

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    Let MM be a manifold and T∗MT^*M be the cotangent bundle. We introduce a 1-cocycle on the group of diffeomorphisms of MM with values in the space of linear differential operators acting on C∞(T∗M).C^{\infty} (T^*M). When MM is the nn-dimensional sphere, SnS^n, we use this 1-cocycle to compute the first-cohomology group of the group of diffeomorphisms of SnS^n, with coefficients in the space of linear differential operators acting on contravariant tensor fields.Comment: arxiv version is already officia

    Relative formality theorem and quantisation of coisotropic submanifolds

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    We prove a relative version of Kontsevich's formality theorem. This theorem involves a manifold M and a submanifold C and reduces to Kontsevich's theorem if C=M. It states that the DGLA of multivector fields on an infinitesimal neighbourhood of C is L-infinity-quasiisomorphic to the DGLA of multidifferential operators acting on sections of the exterior algebra of the conormal bundle. Applications to the deformation quantisation of coisotropic submanifolds are given. The proof uses a duality transformation to reduce the theorem to a version of Kontsevich's theorem for supermanifolds, which we also discuss. In physical language, the result states that there is a duality between the Poisson sigma model on a manifold with a D-brane and the Poisson sigma model on a supermanifold without branes (or, more properly, with a brane which extends over the whole supermanifold).Comment: 31 pages. Details on globalization adde

    The definability criterions for convex projective polyhedral reflection groups

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    Following Vinberg, we find the criterions for a subgroup generated by reflections \Gamma \subset \SL^{\pm}(n+1,\mathbb{R}) and its finite-index subgroups to be definable over A\mathbb{A} where A\mathbb{A} is an integrally closed Noetherian ring in the field R\mathbb{R}. We apply the criterions for groups generated by reflections that act cocompactly on irreducible properly convex open subdomains of the nn-dimensional projective sphere. This gives a method for constructing injective group homomorphisms from such Coxeter groups to \SL^{\pm}(n+1,\mathbb{Z}). Finally we provide some examples of \SL^{\pm}(n+1,\mathbb{Z})-representations of such Coxeter groups. In particular, we consider simplicial reflection groups that are isomorphic to hyperbolic simplicial groups and classify all the conjugacy classes of the reflection subgroups in \SL^{\pm}(n+1,\mathbb{R}) that are definable over Z\mathbb{Z}. These were known by Goldman, Benoist, and so on previously.Comment: 31 pages, 8 figure

    The Design of a Skin Friction Meter for Use in Extreme Environmental Conditions Final Report

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    High altitude, high temperature meter system for skin friction measurement on flying hypersonic ramje

    Consistent Anisotropic Repulsions for Simple Molecules

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    We extract atom-atom potentials from the effective spherical potentials that suc cessfully model Hugoniot experiments on molecular fluids, e.g., O2O_2 and N2N_2. In the case of O2O_2 the resulting potentials compare very well with the atom-atom potentials used in studies of solid-state propertie s, while for N2N_2 they are considerably softer at short distances. Ground state (T=0K) and room temperatu re calculations performed with the new N−NN-N potential resolve the previous discrepancy between experimental and theoretical results.Comment: RevTeX, 5 figure
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