Comments on "Angular Momentum Transport in Quasi-Keplerian Accretion Disks"

Subramanian, Pujari and Becker (2004) claim that the correct expression for the angular momentum transport in an accretion disc, which is proportional to dOmega/dR, can be derived on the basis of the analysis of the epicyclic motion of gas parcels in adjacent eddies in the disc. We study their argument and show that their derivation contains several fundamental errors: 1) the biased choice of the desired formula from an infinite number of formulae; 2) the biased choice of parcel trajectories; and 3) confusion regarding the reference frames. Following 1) we could derive, for example, a (invalid) formula in which the angular momentum transport is proportional to dv_phi/dR, and from 2) we could even prove that the angular momentum transport is either inward or null. We present the correct approach to the problem of angular momentum transport in an accretion disc in terms of mean free path theory.Comment: 9 pages, 2 figures, to appear in Prog. Theor. Phys. Vol.113, No.6, 200

On Kinetic Theory Viscosity in a Rotating Gas

Clarke and Pringle (2004) derived a proper viscosity formula in a rotating gas by applying mean free path theory. We study their argument in detail and show that their result can be derived with a much simpler calculational procedure and physically clearer picture.Comment: 7 pages, 1 figure; Prog. Theor. Phys. Vol. 112, No.

The research about editing system of performance information for player piano - Make inferences about both handed musical composition by using DP matching system -

We have developed a system that allows a piano to perform automatically. In order to play music in the manner of a live pianist, we must add expression to the piano’s performance. Therefore, we have developed an interactive musical editing system that utilizes a database to edit music more efficiently.The 2021 International Conference on Artificial Life and Robotics (ICAROB 2021), January 21-24, 2021, Higashi-Hiroshima (オンライン開催に変更