Atmospheric ducts can transport sound in two directions

Bicarbonate transport in microperfused pancreatic ducts.

Benchmarking two simulation models for underwater and atmospheric sound propagation

Computational wave propagation models are widely used in underwater and atmospheric sound propagation simulation. In most realistic cases the physical domains involved are irregular. We have developed finite element techniques, applied to general irregular meshes and coupled with discrete, artificial absorbing boundary conditions of nonlocal type, for the Helmholtz equation and its ‘standard’ p...

A Coherence Approach to Characterizing Broadband Sound Fields in Ducts

This paper describes a new measurement technique that allows the model amplitude distribution to be determined in ducts with mean flow and reflection based only measurements of the two-point coherence made at the duct wall. The technique is primarily applicable to broadband sound field in the high frequency limit and whose mode amplitudes are incoherent. The technique makes the assumption that ...

New Directions: Atmospheric Brown ‘‘Clouds’’

In February 1999, over 200 scientists from India, Europe and USA gathered in the islands of the Maldives to conduct the Indian Ocean Experiment (INDOEX). As reported by Ramanathan and coworkers (Journal of Geophysical Research, 106 (2001), 371–399), INDOEX revealed the so-called ‘‘brown cloud’’ phenomenon over the Northern Indian Ocean region with a large impact on the solar radiative heating o...

Directions in Internet Transport Evolution

A the Transport Area Open Meeting at IETF 70, area directors Magnus Westerlund and Lars Eggert noted that their queues are empty and that several Transport Area working groups are nearing completion. It may therefore be an opportune time to step back and consider possible directions for new projects in the Transport Area. !is article summarises some of the ideas presented and discussed at that ...