727 research outputs found

    Evaluation of structural safety and seismic vulnerability of historical masonry buildings: studies and applications in the Tuscany Region

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    Recent earthquakes in Italian regions evidenced the high vulnerability of historical masonry existing buildings: severe damages were revealed in structural and not structural elements with the following loss of lives and of significative examples of the Italian architectural tradition, often requiring a strong financial effort to be carried back to their ancient brightness. The majority of the Italian buildings' heritage is made up of masonry constructions with high architectural, historical and monumental impact, enlarged over the centuries without an organized scheme and consequently characterized by structural and not structural problems often increased by the loss of an accurate maintenance. The Italian Standards for Constructions and the guidelines provided by the Ministry for Infrastructures for the evaluation and reduction of seismic risk on historical heritage pay a lot of attention towards the vulnerability analysis of existing buildings, necessary for the elaboration of a project providing higher level of structural static and seismic safety without deleting the original nature of the building. In the present work, the structural analyses of two historical masonry buildings, Palazzo La Sapienza in Pisa and Palazzo Ducale in Massa are presented

    Numerical modelling, analysis and retrofit of the historical masonry building "La Sapienza" in Pisa

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    The evaluation of the structural safety and seismic vulnerability of historical masonry buildings represents one of the most important problems affecting countries, like Italy, characterized by a wide cultural heritage whose original configuration shall be preserved against unexpected seismic events or insufficient maintenance. Recent earthquakes in the Italian regions (Umbria-Marche 1997, Molise 2002, L'Aquila 2009 and Emilia-Romagna 2012) evidenced the high vulnerability of historical masonry buildings, severely damaged in both their structural and not-structural components (i.e. walls, vaults, domes, arches, ornaments and others) and the following significant economic effort required for the execution of retrofit interventions. According to the actual Italian Standard for Constructions (D.M. 14/01/2008) and to the Guidelines provided by the Italian Ministry for Infrastructures for the evaluation and reduction of seismic risk on historical heritage (2010), a multi-level approach is generally adopted for the assessment of the structural safety and seismic vulnerability of ancient masonry buildings and for the design of retrofit interventions. In the present work, the above mentioned multi-level approach is applied to "La Sapienza" Palace in Pisa (Italy). The building, ancient seat of the University of Pisa, was subjected to a wide in situ structural survey and to experimental testing campaigns (including geotechnical analyses, mechanical characterization of materials, structural monitoring and other) allowing the elaboration of a reliable FEM model used for the execution of structural verifications and for the individuation of the main retrofit techniques able to preserve its original nature providing, at the same time, a sufficient margin of structural safety

    Cloaking using the anisotropic multilayer sphere

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    We studied a Spherically Radially Anisotropic (SRA) multilayer sphere with an arbitrary number of layers. Within each layer permittivity components are different from each other in radial and tangential directions. Under the quasi-static approximation, we developed a more generalized mathematical model that can be used to calculate polarizability of the SRA multilayer sphere with any arbitrary number of layers. Moreover, the functionality of the SRA multilayer sphere as a cloak has been investigated. It has been shown that by choosing a suitable contrast between components of the permittivity, the SRA multilayer sphere can achieve threshold required for invisibility cloaking

    Introduction to radar scattering application in remote sensing and diagnostics: Review

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    The manuscript reviews the current literature on scattering applications of RADAR (Radio Detecting And Ranging) in remote sensing and diagnostics. This paper gives prime features for a variety of RADAR applications ranging from forest and climate monitoring to weather forecast, sea status, planetary information, and mapping of natural disasters such as the ones caused by earthquakes. Both the fundamental parameters involved in scattering mechanisms of RADAR applications and the factors affecting RADAR performances are also discusse

    Task demands dissociate the effects of muscarinic M-1 receptor blockade and protein kinase C inhibition on attentional performance in rats

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    The cholinergic system is known to be necessary for normal attentional processing. However, the receptors and mechanisms mediating the effects of acetylcholine on attention remain unclear. Previous work in our laboratory suggested that cholinergic muscarinic receptors are critical for maintaining performance in an attention-demanding task in rats. We examined the role of the muscarinic M-1 receptor and protein kinase C (PKC), which is activated by the M-1 receptor, in attention task performance. Rats were trained in an attention-demanding task requiring discrimination of brief (500, 100, 25 ms) visual signals from trials with no signal presentation. The effects of muscarinic M-1 receptor blockade were assessed by administering dicyclomine (0-5.0 mg/kg). The effects of PKC inhibition were assessed by administering chelerythrine chloride (0-2.0 mg/kg). Dicyclomine decreased the accuracy of detecting longer signals in this attention task, including when attentional demands were increased by flashing a houselight throughout the session. Chelerythrine chloride decreased the accuracy of signal detection in the standard version of the task but not when the houselight was flashed throughout the session. The present findings indicate that muscarinic M-1 receptors are critical for maintaining performance when attentional demands are increased, and that PKC activity may contribute to some aspects of attentional performance

    The potential of apulian olive biodiversity: The case of oliva rossa virgin olive oil

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    In this study, the drupes and virgin olive oils extracted from the Oliva Rossa landrace are characterized. Oliva Rossa is an old landrace part of the autochthonous Apulian olive germplasm for which only few data have been reported till now. During the study, the maturity patterns of the drupes had been followed. Four samplings per year were planned, one every 14 days starting from the middle of October. The pigmentation index, the oil content and the total phenolic content of the drupes were measured. Simultaneously, virgin olive oils were extracted at the lab scale and analyzed for the fatty acid composition, the basic quality parameters and the content of minor compounds. The pigmentation pattern of the drupes was different among the years and, despite this trend, at the third sampling time the stage of maximum oil accumulation was always over. The extracted virgin olive oils had a medium to high level of oleic acid. With colder temperatures, a higher level of monounsaturated fatty acids, oleic/linoleic ratio and antioxidants was observed. The phenolic profile was dominated by 3,4-DPHEA-EDA and p-HPEA-EDA while the volatile profile by (E)-2-hexenal and 3-ethyl-1,5-octadiene

    Finite-Size and Illumination Conditions Effects in All-Dielectric Metasurfaces

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    Dielectric metasurfaces have emerged as a promising alternative to their plasmonic counterparts due to lower ohmic losses, which hinder sensing applications and nonlinear frequency conversion, and their larger flexibility to shape the emission pattern in the visible regime. To date, the computational cost of full-wave numerical simulations has forced the exploitation of the Floquet theorem, which implies infinitely periodic structures, in designing such devices. In this work, we show the potential pitfalls of this approach when considering finite-size metasurfaces and beam-like illumination conditions, in contrast to the typical infinite plane-wave illumination compatible with the Floquet theorem

    Calorimetry of photon gases in nonlinear multimode optical fibers

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    Because of their massless nature, photons do not interact in linear optical media. However, light beam propagation in nonlinear media permits to break this paradigm, and makes it possible to observe photon-photon interactions. Based on this principle, a beam of light propagating in a nonlinear multimode optical system can be described as a gas of interacting particles. As a consequence, the spatio-temporal evolution of this photon gas is expressed in terms of macroscopic thermodynamic variables, e.g., temperature and chemical potential. Moreover, the gas evolution is subject to experiencing typical thermodynamic phenomena, such as thermalization. The meaning of thermodynamic variables associated with the photon gas must not be confused with their classical counterparts, e.g., the gas temperature cannot be measured by means of standard thermometers. Although the thermodynamic parameters of a multimode photon gas result from a rigorous mathematical derivation, their physical meaning is still unclear. In this work, we report on optical calorimetric measurements, which exploit nonlinear beam propagation in multimode optical fibers. Our results show that, indeed, heat only flows from a hot to a cold photon gas subsystem. This provides an unequivocal demonstration that nonlinear multimode wave propagation phenomena are governed by the second law of thermodynamics. In addition to be fundamental, our findings provide a new approach to light-by-light activated management of laser beams

    Polyphenol oxidase genes as integral part of the evolutionary history of domesticated tetraploid wheat.

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    Abstract Studying and understanding the genetic basis of polyphenol oxidases (PPO)-related traits plays a crucial role in genetic improvement of crops. A tetraploid wheat collection ( T. turgidum ssp., TWC) was analyzed using the 90K wheat SNP iSelect assay and phenotyped for PPO activity. A total of 21,347 polymorphic SNPs were used to perform genome-wide association analysis (GWA) in TWC and durum wheat sub-groups, detecting 23 and 85 marker-trait associations (MTA). In addition, candidate genes responsible for PPO activity were predicted. Based on the 23 MTAs detected in TWC, two haplotypes associated with low and high PPO activity were identified. Four SNPs were developed and validated providing one reliable marker (IWB75732) for marker assisted selection. The 23 MTAs were used to evaluate the genetic divergence ( FST > 0.25) between the T. turgidum subspecies , providing new information important for understanding the domestication process of Triticum turgidum ssp. and in particular of ssp. carthlicum
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