PRESSURE-VELOCITY EQUILIBRIUM HYDRODYNAMIC MODELS

This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described.     

Exchange interaction effects in inter-Landau level Auger scattering in a two-dimensional electron gas

We consider the influence of spin effects on the inter-Landau level electron-electron scattering rate in a two-dimensional electron gas. Because of exchange spin splitting, the Landau levels are not equidistant. This leads to the suppression of Auger processes and a nonlinear dependence of the lifetime on the concentration of excited electrons even at very low excitation levels. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 8, 574–579 (25 April 1998) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Evaluation of the Effect of the Furazane Fragment on the NH Acidity of 4- and 5-Picrylaminobenzofurazanes in DMF and DMSO

The products of the reactions of picryl chloride with isomeric aminobenzofurazanes in DMF and DMSO were studied by means of nonaquoeus potentiometric titration. The effect of the position of the furazane fragment in 4- and 5-picrylaminobenzofurazanes on the NH acidity is considered. The electron-acceptor properties of the furazane fragment were evaluated via inclusion of the resulting data into the pK _a-σ correlation for 2,4,6-trinitrodiphenylamines. On this basis, conventional Hammett σ constants were calculated for the furazane fragment located in the immediate vicinity of the N-H center and one position distant from it.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 988–990.(-10V)Original Russian Text Copyright © 2005 by Levinson, Akimova, Ermolaeva, Khairutdinov, Evgen’ev.     

Adaptive computation of articulatory parameters from the speech signal

An unconstrained optimization technique is used to find the values of parameters, of a combination of an articulatory and a vocal tract model, that minimize the difference between model spectra and natural speech spectra. The articulatory model is anatomically realistic and the vocal tract model is a "lossy" Webster equation for which a method of solution is given. For English vowels in the steady state, anatomically reasonable articulatory configurations whose corresponding spectra match those of human speech to within 2 dB have been computed in fewer than ten iterations. Results are also given which demonstrate a limited ability of the system to track the articulatory dynamics of voiced speech.     

The structure and evolution of a skyway network

We study the structure and evolution of the downtown Minneapolis, Minnesota skyway network. Developed by private building-owners, the network evolved from tree-like to grid-like over the course of 50 years. We find that decentralized forces with the goal of maximizing individual buildings’ profitability shaped the network. Our analysis shows that a building with greater office size, a sign of greater accessibility, was more likely to be connected earlier. The distribution of existing skyway segments is found to follow a power-law function of the average degree, closeness, and eigenvector centralities of the vertices. We further explain and model the evolutionary process using an agent-based model. The simulation results suggest that the model replicates the network structure and its evolutionary process.