Compressibility effects on the scalar mixing in reacting homogeneous turbulence

The compressibility and heat of reaction influence on the scalar mixing in decaying isotropic turbulence and homogeneous shear flow are examined via data generated by direct numerical simulations (DNS). The reaction is modeled as one-step, exothermic, irreversible and Arrhenius type. For the shear flow simulations, the scalar dissipation rate, as well as the time scale ratio of mechanical to scalar dissipation, are affected by compressibility and reaction. This effect is explained by considering the transport equation for the normalized mixture fraction gradient variance and the relative orientation between the mixture fraction gradient and the eigenvectors of the solenoidal strain rate tensor.Comment: In Turbulent Mixing and Combustion, eds. A. Pollard and S. Candel, Kluwer, 200

Phonon polariton study of CuCl1-x Brx

Journal ArticleThe optical-phonon spectrum of CuCI-x Brx at low temperature is very unusual in regard to many of its properties. Despite the apparent two-mode behavior our measurements illustrate anomalies in the Raman intensity and temperature-induced frequency shift, as well as in the oscillator strengths yielded by the polariton measurements. All these irregularities are connected to the anomalies of CuCI and they disappear rapidly with increasing Br concentration. The data are interpreted in terms of a previous model, which allows copper ions to occupy off-center sites. It is assumed that in CuC1xBrx this may happen only in the tetrahedra where Cu+ is surrounded by chlorine ions alone

The Use of Phonetic Motor Invariants Can Improve Automatic Phoneme Discrimination

affiliation: Castellini, C (Reprint Author), Univ Genoa, LIRA Lab, Genoa, Italy. Castellini, Claudio; Metta, Giorgio; Tavella, Michele, Univ Genoa, LIRA Lab, Genoa, Italy. Badino, Leonardo; Metta, Giorgio; Sandini, Giulio; Fadiga, Luciano, Italian Inst Technol, Genoa, Italy. Grimaldi, Mirko, Salento Univ, CRIL, Lecce, Italy. Fadiga, Luciano, Univ Ferrara, DSBTA, I-44100 Ferrara, Italy. article-number: e24055 keywords-plus: SPEECH-PERCEPTION; RECOGNITION research-areas: Science & Technology - Other Topics web-of-science-categories: Multidisciplinary Sciences author-email: [email protected] funding-acknowledgement: European Commission [NEST-5010, FP7-IST-250026] funding-text: The authors acknowledge the support of the European Commission project CONTACT (grant agreement NEST-5010) and SIEMPRE (grant agreement number FP7-IST-250026). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. number-of-cited-references: 31 times-cited: 0 journal-iso: PLoS One doc-delivery-number: 817OO unique-id: ISI:000294683900024We investigate the use of phonetic motor invariants (MIs), that is, recurring kinematic patterns of the human phonetic articulators, to improve automatic phoneme discrimination. Using a multi-subject database of synchronized speech and lips/tongue trajectories, we first identify MIs commonly associated with bilabial and dental consonants, and use them to simultaneously segment speech and motor signals. We then build a simple neural network-based regression schema (called Audio-Motor Map, AMM) mapping audio features of these segments to the corresponding MIs. Extensive experimental results show that (a) a small set of features extracted from the MIs, as originally gathered from articulatory sensors, are dramatically more effective than a large, state-of-the-art set of audio features, in automatically discriminating bilabials from dentals; (b) the same features, extracted from AMM-reconstructed MIs, are as effective as or better than the audio features, when testing across speakers and coarticulating phonemes; and dramatically better as noise is added to the speech signal. These results seem to support some of the claims of the motor theory of speech perception and add experimental evidence of the actual usefulness of MIs in the more general framework of automated speech recognition