505 research outputs found
Indoor/Outdoor Air Quality Assessment at School near the Steel Plant in Taranto (Italy)
This study aims to investigate the air quality in primary school placed in district of Taranto (south of Italy), an area of high environmental risk because of closeness between large industrial complex and urban settlement. The chemical characterization of PM2.5 was performed to identify origin of pollutants detected inside school and the comparison between indoor and outdoor levels of PAHs and metals allowed evaluating intrusion of outdoor pollutants or the existence of specific indoor sources. The results showed that the indoor and outdoor levels of PM2.5, BaP, Cd, Ni, As, and Pb never exceeded the target values issued by World Health Organization (WHO). Nevertheless, high metals and PAHs concentrations were detected especially when school were downwind to the steel plant. TheI/Oratio showed the impact of outdoor pollutants, especially of industrial markers as Fe, Mn, Zn, and Pb, on indoor air quality. This result was confirmed by values of diagnostic ratio as B(a)P/B(g)P, IP/(IP + BgP), BaP/Chry, and BaP/(BaP + Chry), which showed range characteristics of coke and coal combustion. However, Ni and As showedI/Oratio of 2.5 and 1.4, respectively, suggesting the presence of indoor sources
Stable lepton mass matrices
Abstract: We study natural lepton mass matrices, obtained assuming the stability of physical flavour observables with respect to the variations of individual matrix elements. We identify all four possible stable neutrino textures from algebraic conditions on their entries. Two of them turn out to be uniquely associated to specific neutrino mass patterns. We then concentrate on the semi-degenerate pattern, corresponding to an overall neutrino mass scale within the reach of future experiments. In this context we show that i) the neutrino and charged lepton mixings and mass matrices are largely constrained by the requirement of stability, ii) naturalness considerations give a mild preference for the Majorana phase most relevant for neutrinoless double-\u3b2 decay, \u3b1 3c \u3c0/2, and iii) SU(5) unification allows to extend the implications of stability to the down quark sector. The above considerations would benefit from an experimental determination of the PMNS ratio 1aU32/U31 1a, i.e. of the Dirac phase \u3b4. \ua9 2016, The Author(s)
Practical considerations for the design of an aeroelastic energy harvester
Achieving the optimal balance between weight and energy consumption during flight mission remains a challenge for the design of very efficient high altitude long endurance aircrafts (HALE). These aircraft are intended to have flight missions that can range from 30 to 90 days. Composite materials are used to provide the structural integrity of the aircraft while minimizing its weight. Typically composites are used in long and slender structural elements of the HALE and are the main drivers of dynamic aeroelastic instabilities, even at low speed. This is due to the higher structural flexibility they introduce. Therefore, in order to respond to the demand of HALE aircrafts of having a wider amount of energy on board, without any substantial weight penalization, an experimental piezoelectric wing have been designed with the aim of exploiting aeroelastic instabilities or any other type of induced vibrations to generate electric energy directly on board. The numerical model of the piezoelectric wing, presented in this paper, is built starting from the assumptions of the 3D Euler-Bernoulli beam theory and of the strip theory for the aerodynamic loads. A preliminary sensitivity study was carried out, over the flutter solutions, for the identification of a suitable experimental prototype, to be used for modal and wind tunnel tests. The test campaign showed a good agreement between numerical and experiments results, highlighting, above all, the encouraging results in terms of energy harvesting and in terms of the exploitation potential of the piezoelectric design in the dynamic of structures
Stable fermion mass matrices and the charged lepton contribution to neutrino mixing
We study the general properties of hierarchical fermion mass matrices in which the small eigenvalues are stable with respect to perturbations of the matrix entries and we consider specific applications to the charged lepton contribution to neutrino mixing. In particular, we show that the latter can account for the whole lepton mixing. In this case a value of sin \u3b813 73 me/m\u3bcsin \u3b823 48 0.03, as observed, can be obtained without the need of any fine-tuning, and present data allow to determine the last row of the charged lepton mass matrix with good accuracy. We also consider the case in which the neutrino sector only provides a maximal 12 rotation and show that i) present data provide a 2\u3c3 evidence for a non-vanishing 31 entry of the charged lepton mass matrix and ii) a plausible texture for the latter can account at the same time for the atmospheric mixing angle, the \u3b813angle, and the deviation of the \u3b812angle from \u3c0/2 without fine-tuning or tension with data. Finally, we show that the so-called \u201cinverted order\u201d of the 12 and 23 rotations in the charged lepton sector can be obtained without fine-tuning, up to corrections of order me/m\u3bc. \ua9 2014, The Author(s)
Results and applications of SiPM photodetectors from FBK-irst by the DASIPM Collaboration
Silicon Photomultipliers (SiPMs) and SiPM matrices optimized for the detection of blue light have been developed at FBK-irst. The first devices produced are composed of 625 microcells with 40 ÎĽm Ă— 40 ÎĽm size, in a 1mm Ă— 1mm active area. The devices have a breakdown voltage around 30 V, and a gain about 106. The DASIPM Collaboration is evaluating their performance and possible applications in high-energy physics, space physics and medical imaging. Dedicated front-end electronics are also being developed
Large theta_13 from a model with broken L_e-L_mu-L_tau symmetry
Recent data in the neutrino sector point towards a relatively large value of
the reactor angle, incompatible with a vanishing theta_ 13 at about 3 sigma. In
order to explain such a result, we propose a SUSY model based on the broken
L_e-L_mu-L_tau symmetry, where large deviations from the symmetric limit
theta_12 = pi/4, tan(theta_23) \sim O(1) and theta_13 = 0 mainly come from the
charged lepton sector. We show that a description of all neutrino data is
possible if the charged lepton mass matrix has a special pattern of complex
matrix elements.Comment: 9 pages, 2 figures. v2: comments and references added, as published
in JHE
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