9,603 research outputs found
On the -algebra in the Calegero-Sutherland model using the Exchange operators
We study the algebra in the Calegero-Sutherland model using the
exchange operators. The presence of all the sub-algebras of is shown
in this model. A simplified proof for this algebra, in the symmetric ordered
basics, is given. It is pointed out that the algebra contains in general,
nonlinear terms. Possible connection to the nonlinear is discussed.Comment: Plain Tex, no figures, 13 page
ASTROP2 users manual: A program for aeroelastic stability analysis of propfans
A user's manual is presented for the aeroelastic stability and response of propulsion systems computer program called ASTROP2. The ASTROP2 code preforms aeroelastic stability analysis of rotating propfan blades. This analysis uses a two-dimensional, unsteady cascade aerodynamics model and a three-dimensional, normal-mode structural model. Analytical stability results from this code are compared with published experimental results of a rotating composite advanced turboprop model and of nonrotating metallic wing model
Penny-shaped crack in a fiber-reinforced matrix
Using a slender inclusion model developed earlier, the elastostatic interaction problem between a penny-shaped crack and elastic fibers in an elastic matrix is formulated. For a single set and for multiple sets of fibers oriented perpendicularly to the plane of the crack and distributed symmetrically on concentric circles, the problem was reduced to a system of singular integral equations. Techniques for the regularization and for the numerical solution of the system are outlined. For various fiber geometries numerical examples are given, and distribution of the stress intensity factor along the crack border was obtained. Sample results showing the distribution of the fiber stress and a measure of the fiber-matrix interface shear are also included
The fermion determinant and the chiral gauge theory on a lattice
Considering as an example a simple lattice ansatz for the chiral fermion
determinant, we demonstrate that even very mild violation of gauge invariance
by the determinant at finite lattice spacing leads to the need for another
scale in the full gauge theory. This new scale is much grater than the lattice
spacing and is associated with the gauge variables.Comment: Talk presented at LATTICE96(chiral gauge), 3 pages, no figures,
espcrc2. References to works of other authors are correcte
Keeping the dream alive: Managing the Space Station Program, 1982 to 1986
The management is described and analyzed of the formative years of the NASA Space Station Program (1982 to 1986), beginning with the successful initiative for program approval by Administrator James M. Beggs through to the decision to bring program management to Reston, Virginia. Emphasis is on internal management issues related to the implementation of the various phases of the program. Themes examined are the problem of bringing programmatic and institutional interests together and focusing them to forward the program; centralized versus decentralized control of the program; how the history of NASA and of the individual installations affected the decisions made; and the pressure from those outside NASA. The four sections are: (1) the decision to build the space station, (2) the design of the management experiment, (3) the experiment comes to life, and (4) the decision reversal
IMPACT OF SHELTERBELTS ON GROUNDNUT PRODUCTION IN THERILANDS: A DECOMPOSITION ANALYSIS.
In areas characterized by wind erosion and shifting sand dunes, shelterbelts can increase crop yields. Groundnut yields in southern India increased with the introduction and maturation of shelterbelts. Decomposition analysis attributed most of the yield increases to the shelterbelts themselves, with a small portion attributed to input use changes. While shelterbelt cost data are scarce, the estimated value of inputs saved due to shelterbelts suggested a net benefit stream that is initially negative but increasing into the indefinite future. Public investments in shelterbelts may be the most effective means of preventing land degradation.Crop Production/Industries,
PRICE SENSITIVITIES FOR U.S. FROZEN DAIRY PRODUCTS
Price elasticities and flexibilities for a system of frozen dessert products are estimated from scanner data. Simultaneity tests reject exogeneity of conditional expenditures, but not prices or quantities, at the weekly level. Inverting the elasticity matrix to obtain flexibilities, while theoretically appropriate, appears to be empirically unacceptable.Demand and Price Analysis,
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