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Full-Text Articles in Social and Behavioral Sciences
Kk-Theory And Spectral Flow In Von Neumann Algebras, J Kaad, R Nest, Adam C. Rennie
Kk-Theory And Spectral Flow In Von Neumann Algebras, J Kaad, R Nest, Adam C. Rennie
Faculty of Engineering and Information Sciences - Papers: Part A
We present a definition of spectral flow for any norm closed ideal J in any von Neumann algebra N. Given a path of selfadjoint operators in N which are invertible in N/J, the spectral flow produces a class in Ko(J).Given a semifinite spectral triple (A, H, D) relative to (N, t) with A separable, we construct a class [D] ? KK1(A, K(N)). For a unitary u ? A, the von Neumann spectral flow between D and u*Du is equal to the Kasparov product [u]A[D], and is simply related to the numerical spectral flow, and a refined C*-spectral flow.
Turbulent Transfer Mechanism In Sediment-Laden Flow, Shu-Qing Yang
Turbulent Transfer Mechanism In Sediment-Laden Flow, Shu-Qing Yang
Faculty of Engineering and Information Sciences - Papers: Part A
Characteristics of turbulent flows in rivers can be significantly modified because of the presence of sediment particles and secondary currents/nonuniformity. This paper investigates why the measured vertical distributions of velocity deviate from the log law. In contrast to previous research that attributed the deviation to Richardson number only, this study demonstrates that like Reynolds shear stress (−equation image), momentum flux (uv) caused by the nonzero wall-normal velocity v is also responsible for these deviations. Starting from Reynolds equations, this paper shows that the classical log law can be obtained only when v = 0; otherwise the velocity v results in …