252,483 research outputs found
Corrosion inhibitors for water-base slurry in multiblade sawing
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
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
Implementation of a trapezoidal ring element in NASTRAN for elastic-plastic analysis
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
Juncture stress fields in multicellular shell structures. Volume V - Influence coefficients of segmental shells
Digital programs to determine stiffness influence coefficients of cylindrical, conical, and spherical shell segments by finite difference metho
Electron and phonon correlations in systems of one-dimensional electrons coupled to phonons
Electron and phonon correlations in systems of one-dimensional electrons
coupled to phonons are studied at low temperatures by emphasizing on the effect
of electron-phonon backward scattering. It is found that the -wave
components of the electron density and phonon displacement field share the same
correlations. Both correlations are quasi-long-ranged for a single conducting
chain coupled to one-dimensional or three-dimensional phonons, and they are
long-ranged for repulsive electron-electron interactions for a
three-dimensional array of parallel one-dimensional conducting chains coupled
to three-dimensional phonons
Permissive Controller Synthesis for Probabilistic Systems
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
Simulations of the Interaction Region in a Photon-Photon Collider
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
Study of basic physical processes in liquid rocket engines
Inconsistencies between analytical results and measurements for liquid rocket thrust chamber performance, which escape suitable explanations, have motivated the examination of the basic phys ical modeling formulations as to their unlimited application. The publication of Prof. D. Straub's book, 'Thermofluid-dynamics of Optimized Rocket Propulsions,' further stimulated the interest of understanding the gas dynamic relationships in chemically reacting mixtures. A review of other concepts proposed by Falk-Ruppel (Gibbsian Thermodynamics), Straub (Alternative Theory, AT), Prigogine (Non-Equilibrium Thermodynamics), Boltzmann (Kinetic Theory), and Truesdell (Rational Mechanism) has been made to obtain a better understanding of the Navier-Stokes equation, which is now used extensively for chemically reacting flow treatment in combustion chambers. In addition to the study of the different concepts, two workshops were conducted to clarify some of the issues. The first workshop centered on Falk-Ruppel's new 'dynamics' concept, while the second one concentrated on Straub's AT. In this report brief summaries of the reviewed philosophies are presented and compared with the classical Navier-Stokes formulation in a tabular arrangement. Also the highlights of both workshops are addressed
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