7,172 research outputs found

    Structural analysis of low-speed composite propfan blades for the LRCSW wind tunnel model

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    The Naval Weapons Center at China Lake, CA, is currently in the process of evaluating propulsion systems for the Long Range Conventional Standoff Weapons (LRCSW). At present, the Advanced Counter-Rotating Propfan system is being considered. The methodologies are documented which were used to structurally analyze the 0.55 scale CM1 composite propfan blades for the LRCSW with COBSTRAN and MSC/NASTRAN. Significant results are also reported

    Analysis of rotating flexible blades using MSC/NASTRAN

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    An overview is given of the use of MSC/NASTRAN in the analysis of rotating flexible blades. The geometrically nonlinear analysis using NASTRAN Solution Sequence 64 is discussed along with the determination of frequencies and mode shapes using Solution Sequence 63. Items unique to rotating blade analysis, such as setting angle, centrifugal softening effects, and hub flexibility, are emphasized

    Yang-Mills streamlines and semi-classical confinement

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    Semi-classical configurations in Yang-Mills theory have been derived from lattice Monte Carlo configurations using a recently proposed constrained cooling technique which is designed to preserve every Polyakov line (at any point in space-time in any direction). Consequently, confinement was found sustained by the ensemble of semi-classical configurations. The existence of gluonic and fermionic near-to-zero modes was demonstrated as a precondition for a possible semi-classical expansion around the cooled configurations as well as providing the gapless spectrum of the Dirac operator necessary for chiral symmetry breaking. The cluster structure of topological charge of the semi-classical streamline configurations was analysed and shown to support the axial anomaly of the right size, although the structure differs from the instanton gas or liquid. Here, we present further details on the space-time structure and the time evolution of the streamline configurations.Comment: Invited talk presented at the conference "Quark confinement and the hadron spectrum IX", Madrid, Aug 30 - Sept 3, 201

    Farm Level Risk Assessment Using Downside Risk Measures

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    Recent and presumable future developments tend to increase the risk associated with farming activities. This causes an increasing importance of risk management. Farmers have a wide variety of possibilities to influence the risk exposure of their operations. Among them are the choice of the production program as well as marketing activities including forward pricing and hedging with futures and options. In total all these opportunities comprise a portfolio of activities which must be selected as to match the resources of the farm as well as the farmer's attitudes towards risk. The paper addresses this issue using a whole farm stochastic optimisation approach based on a risk-value framework. The paper starts with a discussion of risk-value models and the relationship between them and the expected utility hypothesis. In the second part the approach is incorporated in a whole farm model that optimizes a portfolio of production activities and risk management instruments. A case study is used to analyse the possibilities and limitations of the approach and to illustrate the effects of yield and production risk on decision making.downside risk, risk management, risk measure, risk-value models, stochastic optimisation, Risk and Uncertainty,
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