252,487 research outputs found

    Corrosion inhibitors for water-base slurry in multiblade sawing

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    The use of a water-base slurry instead of the standard PC oil vehicle was proposed for multiblade sawing (MBS) silicon wafering technology. Potential cost savings were considerable; however, significant failures of high-carbon steel blades were observed in limited tests using a water-based slurry during silicon wafering. Failures were attributed to stress corrosion. A specially designed fatigue test of 1095 steel blades in distilled water with various corrosion inhibitor solutions was used to determine the feasibility of using corrosion inhibitors in water-base MBS wafering. Fatigue tests indicate that several corrosion inhibitors have significant potential for use in a water-base MBS operation. Blade samples tested in these specific corrosion-inhibitor solutions exhibited considerably greater lifetime than those blades tested in PC oil

    Keynesian Dynamics and the wage price spiral. A baseline disequilibrium approach

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    We reformulate the AS-AD growth model of the Neoclassical Synthesis (Stage I) with its traditional microfoundations. The model still has an LM curve in the place of a Taylor interest rate rule, exhibits sticky wages as well as sticky prices, myopic perfect foresight of current inflation rates and adaptively formed medium run expectations concerning the investment and inflation climate in which the economy is operating. The resulting nonlinear 5D model of labor and goods market disequilibrium dynamics avoids striking anomalies of the standard model of the Neoclassical synthesis. It exhibits instead Keynesian feedback dynamics proper with in particular asymptotic stability of its unique interior steady state for low adjustment speeds and with cyclical loss of stability -- by way of Hopf bifurcations -- when adjustment speeds are made sufficiently large, even leading to purely explosive dynamics sooner or later. In such cases downward money wage rigidity can be used to make the dynamics bounded and thus viable. In this way we obtain and analyze a baseline DAS-AD model with Keynesian feedback channels whose rich set of stability features is the source of business cycle fluctuations. These outcomes of the model stand in contrast to those of the currently fashionable New Keynesian alternative (the Neoclassical Synthesis, Stage II) that we suggest is more limited in scopeDAS-AD growth, wage and price Phiilips curves, real interest rate effects, real wage effects, instability, persistent cycles

    Permissive Controller Synthesis for Probabilistic Systems

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    We propose novel controller synthesis techniques for probabilistic systems modelled using stochastic two-player games: one player acts as a controller, the second represents its environment, and probability is used to capture uncertainty arising due to, for example, unreliable sensors or faulty system components. Our aim is to generate robust controllers that are resilient to unexpected system changes at runtime, and flexible enough to be adapted if additional constraints need to be imposed. We develop a permissive controller synthesis framework, which generates multi-strategies for the controller, offering a choice of control actions to take at each time step. We formalise the notion of permissivity using penalties, which are incurred each time a possible control action is disallowed by a multi-strategy. Permissive controller synthesis aims to generate a multi-strategy that minimises these penalties, whilst guaranteeing the satisfaction of a specified system property. We establish several key results about the optimality of multi-strategies and the complexity of synthesising them. Then, we develop methods to perform permissive controller synthesis using mixed integer linear programming and illustrate their effectiveness on a selection of case studies

    Juncture stress fields in multicellular shell structures. Volume V - Influence coefficients of segmental shells

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    Digital programs to determine stiffness influence coefficients of cylindrical, conical, and spherical shell segments by finite difference metho

    Implementation of a trapezoidal ring element in NASTRAN for elastic-plastic analysis

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    The explicit expressions for an elastic-plastic trapezoidal ring element are presented and implemented in NASTRAN computer program. The material is assumed to obey the von Mises' yield criterion, isotropic hardening rule and the Prandtl-Reuss flow relations. For the purpose of demonstration, two elastic-plastic problems are solved and compared with previous results. The first is a plane-strain tube under uniform internal pressure and the second, a finite-length tube loaded over part of its inner surface. A very good agreement was found in both test problems

    Simulations of the Interaction Region in a Photon-Photon Collider

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    The status and initial performance of a simulation program CAIN for interaction region of linear colliders is described. The program is developed to be applicable for e+e-, e-e-, e-gamma and gamma-gamma linear colliders. As an example of an application, simulation of a gamma-gamma collider option of NLC is reported.Comment: 16 pages, 6 eps figures, use epsf.st

    Stem-root flow effect on soil–atmosphere interactions and uncertainty assessments

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    Abstract. Soil water can rapidly enter deeper layers via vertical redistribution of soil water through the stem–root flow mechanism. This study develops the stem–root flow parameterization scheme and coupled this scheme with the Simplified Simple Biosphere model (SSiB) to analyze its effects on land–atmospheric interactions. The SSiB model was tested in a single column mode using the Lien Hua Chih (LHC) measurements conducted in Taiwan and HAPEX-Mobilhy (HAPEX) measurements in France. The results show that stem–root flow generally caused a decrease in the moisture content at the top soil layer and moistened the deeper soil layers. Such soil moisture redistribution results in significant changes in heat flux exchange between land and atmosphere. In the humid environment at LHC, the stem–root flow effect on transpiration was minimal, and the main influence on energy flux was through reduced soil evaporation that led to higher soil temperature and greater sensible heat flux. In the Mediterranean environment of HAPEX, the stem–root flow significantly affected plant transpiration and soil evaporation, as well as associated changes in canopy and soil temperatures. However, the effect on transpiration could either be positive or negative depending on the relative changes in the moisture content of the top soil vs. deeper soil layers due to stem–root flow and soil moisture diffusion processes
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