A MODAL APPROACH FORREVERBERATION TIME MEASUREMENTS IN NON-DIFFUSE SOUND FIELD

In recent years the extension of reverberation time measurements to frequencies below 100 Hz is becoming more and more important due to the increase of low frequency sources. In ordinary rooms with volumes smaller than 200 m3the low frequency sound field is non-diffuse due to the presence of modes, which are also the main cause of bad quality of listening in terms of clarity and rumble effects. Since standard measurements according to ISO 3382 fail to achieve accurate and precise values in third octave bands due to non-linear decays of room modes, a new ap-proach based on reverberation time measurements of single resonant frequencies (the modal re-verberation time) is introduced. Two measurementmethods based on the relation between mod-al decays and resonant half bandwidths are proposed: the direct method, based on the direct evaluation of modal sound decays with interrupted source signals, and the indirect method based on half bandwidth measurements. Proper measurement procedures, with microphones placed at rectangular room corners and anti-resonant sine waves and sweep source signals for direct and indirect measurement methods respectively, are proposed. Comparison between direct and indi-rect methods shows good and significant agreement. Comparing modal reverberation times with standard ones, the inadequacy of standard procedure to get accurate and precise values at low frequencies with respect to the modal approach becomes evident. In the future, further investi-gations are necessary in more rooms toimprove uncertainty evaluation

Reverberation time measurements in non-diffuse acoustic field by the modal reverberation time

partially_open3mixedPrato, A.; Casassa, F.; Schiavi, A.Prato, A.; Casassa, F.; Schiavi, Alessandr

Work Function Tuning in Hydrothermally Synthesized Vanadium-Doped MoO3 and Co3O4 Mesostructures for Energy Conversion Devices

The wide interest in developing green energy technologies stimulates the scientific community to seek, for devices, new substitute material platforms with a low environmental impact, ease of production and processing and long-term stability. The synthesis of metal oxide (MO) semiconductors fulfils these requirements and efforts are addressed towards optimizing their functional properties through the improvement of charge mobility or energy level alignment. Two MOs have rising perspectives for application in light harvesting devices, mainly for the role of charge selective layers but also as light absorbers, namely MoO3 (an electron blocking layer) and Co3O4 (a small band gap semiconductor). The need to achieve better charge transport has prompted us to explore strategies for the doping of MoO3 and Co3O4 with vanadium (V) ions that, when combined with oxygen in V2O5, produce a high work function MO. We report on subcritical hydrothermal synthesis of V-doped mesostructures of MoO3 and of Co3O4, in which a tight control of the doping is exerted by tuning the relative amounts of reactants. We accomplished a full analytical characterization of these V-doped MOs that unambiguously demonstrates the incorporation of the vanadium ions in the host material, as well as the effects on the optical properties and work function. We foresee a promising future use of these materials as charge selective materials in energy devices based on multilayer structures

Targeting G protein-coupled receptors with magnetic carbon nanotubes:The Case of the A ₃ Adenosine Receptor

A 3 adenosine receptor (AR) is a G protein-coupled receptor (GPCR) overexpressed in the membrane of specific cancer cells. Thus, the development of nanosystems targeting this receptor could be a strategy to both treat and diagnose cancer. Fe-filled carbon nanotubes (CNTs) are an optimal platform for theranostic purposes, and the use of a magnetic field can be exploited for cancer magnetic cell sorting and thermal therapy. In this work, we have conjugated an A 3 AR ligand on the surface of Fe-filled CNTs with the aim to target cells overexpressing A 3 ARs. In particular, two conjugates bearing PEG linkers of different length were designed. A docking analysis on the A 3 AR showed that both CNT and linker do not interfere with ligand binding to the receptor, that was confirmed by in vitro preliminary radioligand competition assays on A 3 AR. Encouraged by this result, magnetic cell sorting was applied to a mixture of cells overexpressing or not the A 3 AR where our compound resulted to not be selective for A 3 AR-cancer cells. Despite this, it is the first time that a GPCR ligand was anchored to a magnetic nanosystem, thus it opens the door to new applications for cancer treatment

Work Function Tuning in Hydrothermally Synthesized Vanadium-Doped MoO3 and Co3O4 Mesostructures for Energy Conversion Devices

The wide interest in developing green energy technologies stimulates the scientific community to seek, for devices, new substitute material platforms with a low environmental impact, ease of production and processing and long-term stability. The synthesis of metal oxide (MO) semiconductors fulfils these requirements and efforts are addressed towards optimizing their functional properties through the improvement of charge mobility or energy level alignment. Two MOs have rising perspectives for application in light harvesting devices, mainly for the role of charge selective layers but also as light absorbers, namely MoO3 (an electron blocking layer) and Co3O4 (a small band gap semiconductor). The need to achieve better charge transport has prompted us to explore strategies for the doping of MoO3 and Co3O4 with vanadium (V) ions that, when combined with oxygen in V2O5, produce a high work function MO. We report on subcritical hydrothermal synthesis of V-doped mesostructures of MoO3 and of Co3O4, in which a tight control of the doping is exerted by tuning the relative amounts of reactants. We accomplished a full analytical characterization of these V-doped MOs that unambiguously demonstrates the incorporation of the vanadium ions in the host material, as well as the effects on the optical properties and work function. We foresee a promising future use of these materials as charge selective materials in energy devices based on multilayer structures

Mechanochemical Synthesis of Sn(II) and Sn(IV) Iodide Perovskites and Study of Their Structural, Chemical, Thermal, Optical and Electrical Properties

Phase‐pure CsSnI3, FASnI3, Cs(PbSn)I3, FA(PbSn)I3 perovskites (FA = formamidinium = HC(NH2)2+) as well as the analogous so‐called vacancy‐ordered double perovskites Cs2SnI6 and FA2SnI6 are mechanochemically synthesized. The addition of SnF2 is found to be crucial for the synthesis of Cs‐containing perovskites but unnecessary for hybrid ones. All compounds show an absorption onset in the near‐infrared (NIR) region, which makes them especially relevant for photovoltaic applications. The addition of Pb(II) and SnF2 is crucial to improve the electronic properties in 3D Sn(II)‐based perovskites, in particular their charge carriers mobility (≈0.2 cm2 Vs−1) which is enhanced upon reduction of the dark carrier conductivity. Stokes‐shifted photoluminescence is observed on dry powders of Sn(II)‐based perovskites, which makes these materials promising for light‐emitting and sensing applications. Thermal stability of all compounds is examined, revealing no significant degradation up to at least 200 °C. This meets the requirements for standard operation conditions of most optoelectronic devices and is potentially compatible with thermal vacuum deposition of polycrystalline thin films

An Exploratory Study of Field Failures

Field failures, that is, failures caused by faults that escape the testing phase leading to failures in the field, are unavoidable. Improving verification and validation activities before deployment can identify and timely remove many but not all faults, and users may still experience a number of annoying problems while using their software systems. This paper investigates the nature of field failures, to understand to what extent further improving in-house verification and validation activities can reduce the number of failures in the field, and frames the need of new approaches that operate in the field. We report the results of the analysis of the bug reports of five applications belonging to three different ecosystems, propose a taxonomy of field failures, and discuss the reasons why failures belonging to the identified classes cannot be detected at design time but shall be addressed at runtime. We observe that many faults (70%) are intrinsically hard to detect at design-time