171,228 research outputs found
Applying a combined metric based on fluctuation characteristics to outline the impact of noises in the classrooms
No full textIn a companion paper by the same authors (N. Prodi and C. Visentin, "Revising fluctuation noise characteristics for describing the reception of speech in rooms with a combined metric", Proc. of INTERNOISE2013, Innsbruck 15-18 September 2013) a novel combined objective metric for assessing the role of noise fluctuations on word recognition in rooms was presented and discussed. The parameter is termed "speech fluctuation quality index" SFQI and includes both an indirect evaluation of the noise modulations on the signal plus noise combination and a loudness discrimination correction. The approach, matched to closed set DRT tests, allows to evaluate each noise separately and this feature is mostly relevant in classrooms, where the disturbances are of various nature and each has its own fluctuation attributes. In the present work it is shown how the SFQI is able to segregate the noises, and works when STI substantially fails. The pupils' performance is thus much better depicted especially when the "listening efficiency" subjective data are considered in the analysis. Applications of this objective/subjective approach will be fostered in other contexts too
Public Space in Motion. Progettare il vuoto. Conversazione di Chiara Visentin con Isotta Cortesi, architetto e docente di Composizione architettonica alla Facoltà di Architettura di Siracusa.
No full textEffects of multiple early diffuse reflections on spatial percepts
No full textWhile the use of diffuse surfaces is becoming increasingly common in the acoustical design of performance venues and normal rooms, there is a paucity of data on the auditory perceptual effects that characterize those finishes compared to specular ones. For instance, it is not entirely clear whether and how the aural impression is affected when first reflections are swapped from specular to diffuse. In a recent work, after revising the background knowledge on physical and perceptual effects of scattering, Visentin et al. [(2020) J. Acoust. Soc. Am. 148(1), 122-140] started a systematic analysis of how diffuse reflections influence the auditory impression by considering the simplest possible case, that is, a direct sound and one lateral reflection. The present work is a step forward in the analysis, and pairs of lateral reflections without or with a ceiling reflection are considered. By means of detailed listening tests, it is shown how diffuse reflections modulate the perception of some spatial attributes. This knowledge adds to the criteria to be employed when including diffusing surfaces in the design of first reflections in rooms
Insertion of isocyanides across the Pd-C bond in alkyl or aryl palladium(II) complexes bearing mixed nitrogen-sulfur and nitrogen-phosphorus ancillary ligands. The mechanism of reaction
No full textAn exhaustive study dealing with the kinetic and mechanistic behavior of alkyl- and arylpalladium complexes bearing pyridyl-thioethers (NS-R) and quinoline-phosphines (NP) as ancillary ligands when reacting with 2,6-dimethyl isocyanide (DIC) and tosylmethyl isocyanide (TosMIC) was undertaken. In these reactions some differently substituted isocyanides insert into the palladium -carbon bond of alkyl and aryl complexes bearing mixed (NS or NP) ligands. The reactions were carried out under equimolecular conditions since such a restrictive approach allows the determination of the rate constants related to the isocyanide insertion attack. Reactions carried out under nonstoichiometric conditions were also taken into account and the reaction products characterized. Usually the formation of an inserted bis-substituted isocyanide halide derivative of palladium(II) was observed. In a particular case the formation of an imidoyl dimer was detected. The structures of the monoinserted [Pd(NSt-Bu)((C(Tol)=NR2)I] (NSt-Bu = 2-(tertbutylthiomethyl)pyridine) and of the dimer [Pd(CNR 2) (C(=NR2)Me)C( (R-2 = 2,6-Me2C6H3) were reported
Ceramic facing tiles (EN 159) obtained from dry-ground Italian raw materials. Part I.
No full textOptimization of dry grinding of paste, contg. exclusively Italian raw materials, for use in prodn. of porous ceramic facing tiles (EN 159) was studied using a rolling vertical mill (Pfeiffer MPS 141A); the results obtained demonstrate that it is possible, using cycles of single-firing (39 min at max. temp 1080 C) and rapid double-firing (28 min firing, 7 min drying, inertization at max. temp 1065 C, and glazing 45 min at max. temp. 1055 C), to obtain products with the functional properties required by the strict European std. Baiso 160 clay is predominantly illite and chlorite with high contents of Ca and Mg oxides; Alloero Refrattoria is predominantly illite and chlorite with high content of free qt and trace carbonates
Objective characterization of speech intelligibility under continuous fluctuating masker: Comparing speech transmission index (STI) and speech fluctuation quality index (SFQI)
No full textWhen a listener is exposed to babble noise in a room or space, the reception of speech is influenced by the amount of temporal fluctuations present in the disturbance which in turn is mediated by the sound tail in the room. In order to investigate these conditions a set of simulated signals having different ratios of single talker and babble was prepared for a range of reverberation times. Two regular rooms with volumes equal to 352m3 and 3072m3 respectively were chosen for simulating the sound tails, and the reverberated signals were characterized by means of their "fluctuation strength". It was shown that the overall room dimensions and hence the impulse response details play a minor role whereas the reverberation time drives the behavior of noise fluctuations. Then the objective characterization of speech intelligibility in the rooms was accomplished for a number conditions by means of STI, which is known to behave critically under fluctuating masker conditions. Also the recently proposed speech fluctuation quality index SFQI, which is based on the comparison of fluctuations in the signal with those in the noise, was calculated. This latter indicator effectively separates the different noise fluctuation groups. Finally, recordings in real environments (bar, restaurant, market, bus) were accomplished and a first comparison with simulated conditions was discussed.When a listener is exposed to babble noise in a room or space, the reception of speech is influenced by the amount of temporal fluctuations present in the disturbance which in turn is mediated by the sound tail in the room. In order to investigate these conditions a set of simulated signals having different ratios of single talker and babble was prepared for a range of reverberation times. Two regular rooms with volumes equal to 352m3 and 3072m3 respectively were chosen for simulating the sound tails, and the reverberated signals were characterized by means of their "fluctuation strength". It was shown that the overall room dimensions and hence the impulse response details play a minor role whereas the reverberation time drives the behavior of noise fluctuations. Then the objective characterization of speech intelligibility in the rooms was accomplished for a number conditions by means of STI, which is known to behave critically under fluctuating masker conditions. Also the recently pr..
The Padova Type 2 Diabetes Simulator from Triple-Tracer Single-Meal Studies: In Silico Trials Also Possible in Rare but Not-So-Rare Individuals
No full textBackground: In silico trials in type 2 diabetes (T2D) would be useful for testing diabetes treatments and accelerating the development of new antidiabetic drugs. In this study, we present a T2D simulator able to reproduce the variability observed in a T2D population. The simulator also allows to safely experiment on virtual subjects with severe (and possibly rare) pathological conditions. Methods: A meal simulation model of glucose, insulin, and C-peptide systems, made of 15 differential equations and 39 parameters, has been identified using a system decomposition and forcing function Bayesian strategy on data of 51 T2D subjects undergoing a single triple-tracer mixed meal. One hundred T2D in silico subjects have been generated from the joint distribution of estimated model parameters. A case study is presented to illustrate the simulator use for testing a virtual drug (improving insulin action and secretion) in a subpopulation of rare, extremely impaired, T2D subjects. Results: The model well fitted T2D data and parameters were estimated with precision. Simulated plasma glucose, insulin, and C-peptide well matched the data (e.g., median [25th-75th percentile] glucose area under the curves of 6.9 [6.1-8.5] 104 mg/dL·min in silico vs. 7.0 [5.6-8.2] 104 mg/dL·min in vivo). The potential use of the simulator was shown in a case study, in which the (virtual) antidiabetic drug dose was optimized for very insulin-resistant T2D subjects. Conclusions: We have developed a T2D simulator that captures the behavior of T2D population during a meal, both in terms of average and intersubject variability. The simulator represents a cost-effective way to test new antidiabetic drugs, before moving to human trials
Synthesis, characterization, dynamics and reactivity toward amination of η3-allyl palladium complexes bearing mixed ancillary ligands. Evaluation of the electronic characteristics of the ligands from kinetic data.
No full textOn the basis of an original protocol, we have synthesized several complexes of the type [Pd(eta(3)-C(3)H(3)R(2))(LL')]ClO(4) (R = H, Me; L, L' = PPh(3), P(OEt)(3), 2,6-dimethylphenylisocyanide, t-butylisocyanide, 1,3-dimesitylimidazolidine, 1,3-dimesitylimidazol-2-ylidene). The complexes, some of which are completely new species, were fully characterized and their behaviour in solution was studied by means of (1)H NMR. The reactions of the complexes bearing the symmetric allyl moiety [Pd(eta(3)-C(3)H(5))(LL')]ClO(4) with piperidine in the presence of the olefin dimethylfumarate were followed under kinetically controlled conditions. Formation of allyl-amine and of the palladium(0) derivatives [Pd(eta(2)-dmfu)(LL'] was observed. The reaction rates k(2) proved to be strongly dependent on the ancillary ligand nature and allowed a direct comparison among the electronic characteristics of the ligands. The reactivity trend determined appears to be mainly influenced by the capability of the ancillary ligands in transferring electron density to the metal centre and consequently on the allyl fragment
Calculating the speech transmission index in fluctuating noise: A data-driven approach in the short-term implementation
No full textEveryday communication takes place in the concurrent presence of reverberation and background noise; the latter may have a fluctuating character and a speech-like spectrum, being for instance the result of multiple speakers talking together in the background (i.e., babble noise). The objective characterization of these listening conditions can be achieved by using a time-frame implementation of the Speech Transmission Index (STI) in the indirect scheme, named eSTI. One prerequisite of using the method is that the optimal time frame has to be determined. In this study, an experimental approach was used to determine the optimal time frame, defined as the one that provides coincident psychometric curves under stationary and fluctuating background noises. Matrixed-word listening tests were presented to 79 young adults with normal hearing. The speech reception task was presented under 26 listening conditions, created by varying signal-to-noise ratio, reverberation and noise type. By comparing the psychometric curves for the two noises, an interval of suitable frame durations was identified, ranging between 200 and 345 ms. Using a time frame within this interval thus ensures that the same eSTI value corresponds to the same predicted intelligibility, irrespective of the noise type
- …
