96,649 research outputs found
Hopf, J. an Herman Grimm (1 Brief)
No full textHOPF, J. AN HERMAN GRIMM (1 BRIEF)
Hopf, J. an Herman Grimm (1 Brief) (Br3212)
Brief 3212 (Br3212
The Wiener-Hopf solution of the isotropic penetrable wedge problem: diffraction and total field
No full textThe diffraction of an incident plane wave by an isotropic penetrable wedge is studied using generalized Wiener-Hopf equations, and the solution is obtained using analytical and numerical-analytical approaches that reduce the Wiener-Hopf factorization to Fredholm integral equations of second kind. Mathematical aspects are described in a unified and consistent theory for angular region problems. The formulation is presented in the general case of skew incidence and several numerical tests at normal incidence are reported to validate the new technique. The solutions consider engineering applications in terms of GTD/UTD diffraction coefficients and total field
Suppression of Hopf bifurcation in metal cutting by extrusion machining
No full textHopf bifurcation is a common phenomenon during the metal cutting process which results in poor surface finish of the workpiece and inhomogeneous grain structure in materials. Therefore understanding and controlling Hopf bifurcation in metal cutting are necessary. In this work the systematic low-speed extrusion machining experiments were conducted to suppress Hopf bifurcation phenomenon. It is found that the suppression of Hopf bifurcation is achieved with the increasing constraint extrusion degree. In order to reveal the mechanism of the suppression of Hopf bifurcation a new nonlinear dynamic model for extrusion machining is developed where the convection the diffusion the extrusion of constraint the thermal-softening deformation and the fracture-type damage are included. The theoretical predictions are in agreement with the experimental results; therefore the present theoretical model is effective to characterize the suppression of Hopf bifurcation in metal cutting. Based on the numerical calculation of the theoretical model the mechanisms underlying in extrusion machining are further revealed: Fracture-type deformation is more important than the thermal-softening-type deformation in low-speed extrusion machining; however the thermal-softening-type deformation is the primary deformation mode for high-speed extrusion machining
A trifurcated waveguide problem II
No full textWe consider the diffraction of the dominant plane wave mode which propagates out of the end of a semi-infinite waveguide. This waveguide is made up of a half plane with a Dirichlet boundary condition and a half plane with a Neumann boundary condition. This semi-infinite waveguide is symmetrically located inside another infinite waveguide one of whose infinite plates has a Dirichlet and the other a Neumann boundary condition. A closed form solution of the resulting matrix Weiner-Hopf equation is obtained
Diffraction by an acoustically penetrable or an electromagnetically dielectric half plane II
No full textThe present work gives a mathematical model for an acoustically penetrable or electromagnetically dielectric half plane. An approximate boundary condition is derived which depends on the thickness of, and the material constants which constitutes, the half plane. A solution is obtained, using the approximate boundary condition, for the problem of a line source field diffracted by a semi-infinite penetrable/dielectric half plane. The asymmetry of the approximate boundary condition results in a matrix Wiener-Hopf problem, which is solved explicitly
[Report to Chief J. E. Curry, by an unknown author #1]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
A trifurcated waveguide problem
No full textWe consider the diffraction of the dominant wave mode which propagates out of the mouth of a semi-infinite waveguide made of a soft and hard half plane. This semi-infinite waveguide is symmetrically located inside an infinite waveguide whose infinite plates are soft and hard. The whole system constitutes a trifurcated waveguide. A closed form solution of the resulting matrix Wiener-Hopf equation is obtained
Hopf bracoids
No full textThe present article is devoted to introduce the notion of Hopf bracoid in the
braided monoidal framework as the quantum version of skew bracoids, which have
been presented by Martin-Lyons and Paul J. Truman. Taking into account that
Hopf braces are particular examples of Hopf bracoids, in this paper we
generalize many properties of Hopf braces to the Hopf bracoid setting and we
obtain a categorical isomorphism between certain full subcategories of the Hopf
bracoids category and the 1-cocycles category.Comment: arXiv admin note: text overlap with arXiv:2311.0523
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