24,935 research outputs found
High-temperature ''hydrostatic'' extrusion
Quasi-fluids permit hydrostatic extrusion of solid materials. The use of sodium chloride, calcium fluoride, or glasses as quasi-fluids reduces handling, corrosion, and sealing problems, these materials successfully extrude steel, molybdenum, ceramics, calcium carbonate, and calcium oxide. This technique also permits fluid-to-fluid extrusion
Applications to aeronautics of the theory of transformations of nonlinear systems
The development of the transformation theory is discussed. Results and applications concerning the use of this design technique for automatic flight control of aircraft are presented. The theory examines the transformation of nonlinear systems to linear systems. The tracking of linear models by nonlinear plants is discussed. Results of manned simulation are also presented
Canonical forms for nonlinear systems
Necessary and sufficient conditions for transforming a nonlinear system to a controllable linear system have been established, and this theory has been applied to the automatic flight control of aircraft. These transformations show that the nonlinearities in a system are often not intrinsic, but are the result of unfortunate choices of coordinates in both state and control variables. Given a nonlinear system (that may not be transformable to a linear system), we construct a canonical form in which much of the nonlinearity is removed from the system. If a system is not transformable to a linear one, then the obstructions to the transformation are obvious in canonical form. If the system can be transformed (it is called a linear equivalent), then the canonical form is a usual one for a controllable linear system. Thus our theory of canonical forms generalizes the earlier transformation (to linear systems) results. Our canonical form is not unique, except up to solutions of certain partial differential equations we discuss. In fact, the important aspect of this paper is the constructive procedure we introduce to reach the canonical form. As is the case in many areas of mathematics, it is often easier to work with the canonical form than in arbitrary coordinate variables
A general model for motivational analyses of exchange relationships
Model for motivational analysis of exchange relationships between consumer and supplie
Individual and corporate sources of motivation - A preliminary investigation
Rating scales of individual and corporate motivations and factor analysis of result
Asymptotic Multi-Layer Analysis of Wind Over Unsteady Monochromatic Surface Waves
Asymptotic multi-layer analyses and computation of solutions for turbulent
flows over steady and unsteady monochromatic surface wave are reviewed, in the
limits of low turbulent stresses and small wave amplitude. The structure of the
flow is defined in terms of asymptotically-matched thin-layers, namely the
surface layer and a critical layer, whether it is elevated or immersed,
corresponding to its location above or within the surface layer. The results
particularly demonstrate the physical importance of the singular flow features
and physical implications of the elevated critical layer in the limit of the
unsteadiness tending to zero. These agree with the variational mathematical
solution of Miles (1957) for small but finite growth rate, but they are not
consistent physically or mathematically with his analysis in the limit of
growth rate tending to zero. As this and other studies conclude, in the limit
of zero growth rate the effect of the elevated critical layer is eliminated by
finite turbulent diffusivity, so that the perturbed flow and the drag force are
determined by the asymmetric or sheltering flow in the surface shear layer and
its matched interaction with the upper region. But for groups of waves, in
which the individual waves grow and decay, there is a net contribution of the
elevated critical layer to the wave growth. Critical layers, whether elevated
or immersed, affect this asymmetric sheltering mechanism, but in quite a
different way to their effect on growing waves. These asymptotic multi-layer
methods lead to physical insight and suggest approximate methods for analyzing
higher amplitude and more complex flows, such as flow over wave groups.Comment: 20 page
Incentive contracting - An annotated and classified modern bibliography
Incentive contracts bibliograph
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