Numerical Study of Velocity Statistics in Steady Counterflow Quantum Turbulence

We investigate the velocity statistics by calculating the Biot--Savart velocity induced by vortex filaments in steady counterflow turbulence investigated in a previous study [Phys. Rev. B {\bf 81}, 104511 (2010)]. The probability density function (PDF) obeys a Gaussian distribution in the low-velocity region and a power-law distribution $v^{-3}$ in the high-velocity region. This transition between the two distributions occur at the velocity characterized by the mean inter-vortex distance. Counterflow turbulence causes anisotropy of the vortex tangle, which leads to a difference in the PDF for the velocities perpendicular to and parallel to the counterflow.Comment: 4 pages, 7 figure

Recent progress in silica aerogel Cherenkov radiator

In this paper, we present recent progress in the development of hydrophobic silica aerogel as a Cherenkov radiator. In addition to the conventional method, the recently developed pin-drying method for producing high-refractive-index aerogels with high transparency was studied in detail. Optical qualities and large tile handling for crack-free aerogels were investigated. Sufficient photons were detected from high-performance aerogels in a beam test.Comment: Proceedings of 2nd International Conference on Technology and Instrumentation in Particle Physics (TIPP 2011), to be published in Physics Procedia, 8 pages, 7 figure

Option Package Bundling

This paper analyzes the optimality of package bundling by focusing on the ?main and accessory?relationship between two goods. In particular, we consider option package bundling in which an optional good is valuable only if it is consumed together with a certain (nonoptional) base good. We develop a model of option package bundling for a monopolist in which buyers?valuations are independently and uniformly distributed. We also allow inter-relationship between valuations by assuming that the reservation value of the bundle can be greater or less than the sum of the innate value of both goods. Our analysis observes that mixed bundling, in which the base good is sold with or without the optional good, yields a higher pro?t than pure bundling if and only if the range of the optional good valuation exceeds a threshold value. We then conduct a welfare analysis of the bundling choice. The result is surprising: pure bundling is always desirable from the social welfare viewpoint when a monopolist chooses mixed bundling.Multiproduct monopoly; Bundling; Optional goods; Interdepen-dent valuations.

Numerical simulation of transfer and attenuation characteristics of soft-tissue conducted sound originating from vocal tract

A non-audible murmur (NAM), a very weak speech sound produced without vocal cord vibration, can be detected by a special NAM microphone attached to the neck, thereby providing a new speech communication tool for functional speech disorders as well as human-to-machine and human-to-human interfaces with inaudible voice input for use with unimpaired. The NAM microphone is a condenser microphone covered with soft-silicone impression material that provides good impedance matching with the soft tissues of the neck. Because higher-frequency components are suppressed severely, however, the NAM detected with this device can be insufficiently clear. To improve NAM clarity, the mechanism of NAM production as well as the transfer characteristics of the NAM in soft neck tissues must be clarified. We have investigated sound propagation from the vocal tract to the neck surface, using a finite difference time domain method and a head model based on magnetic resonance imaging scans. Numerical results show that, compared to air-conducted sound detected in front of a mouth, soft-tissue-conducted sound attenuates 50 dB at 1 kHz, which consists of 30 dB full-range attenuation due to air-to-soft-tissues transmission loss and -10 dB/octave spectral decay due to a propagation loss in soft tissues. The decay agrees well with the spectral characteristics of the measured NAM. (C) 2008 Elsevier Ltd. All rights reserved.ArticleAPPLIED ACOUSTICS. 70(3):469-472 (2009)journal articl