936 research outputs found

    Innovazione dei setting per la didattica universitaria

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    In recent years, Italian universities have been called upon to experiment with innovative processes and changes that have involved different aspects. This contribution focuses in particular on the factors related to teaching that influence the design of university settings, characterized by student\u2019s profile evolution, the pervasiveness of the media and the ever-increasing demand to develop skills. and achieve the stated training goals are some aspects that have influenced the teaching. BYOD, inverted classroom, feedback, experience learning are considered relevant factors for the re-definition of settings for university teaching Starting from two approaches, teacher or student-centered, some scenarios that could characterize in the next decades the following university settings: the lecture hall, the small classroom in presence, the online synchronous environments and the asynchronous online environments

    Wavelet entropy and fractional Brownian motion time series

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    We study the functional link between the Hurst parameter and the Normalized Total Wavelet Entropy when analyzing fractional Brownian motion (fBm) time series--these series are synthetically generated. Both quantifiers are mainly used to identify fractional Brownian motion processes (Fractals 12 (2004) 223). The aim of this work is understand the differences in the information obtained from them, if any.Comment: 10 pages, 2 figures, submitted to Physica A for considering its publicatio

    Direct and indirect costs in the conservative management of undisplaced scaphoid fractures

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    The scaphoid is the most commonly fractured carpal bone, and preferable treatment of undisplaced fractures is controversial. In order to assess the socio-economic impact of treatment modalities, we analysed the cost of conservative management of 54 undisplaced scaphoid fractures. Global costs amounted to 14.077 Swiss francs (9385 euros) per patient. Direct costs represent only 10% of global costs. No significant correlation was found between costs and timing of diagnosis, hand dominance or complications. Thirty-four percent of patients were able to resume their job with the wrist immobilised without complication, but at an obvious impact on indirect and global costs. If early resumption of professional activities during conservative treatment of undisplaced scaphoid fractures does not impair successful fracture healing, patients should be encouraged to return to work as early as possible, as is routinely done after percutaneous fracture fixation. This will contribute to massively reducing the cost of conservative treatmen

    The stone roof of the tholos of Athena Pronaia in Delphi: structural hypotheses starting from fragments of marble tiles

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    This contribution is the first step of a multi-disciplinary research project, aimed at studying the roof of the tholos of Athena Pronaia in Delphi, dating back to the first decades of the 4th century BC. The starting point of this research is the fascination exerted by the tectonic quality of the temple, comprising some complex fragments of marble tiles belonging to the roof of the tholos. Despite the number of studies on this sanctuary, the poor state of preservation and lack of original material did not allow archaeologists to perform concluding research on its original configuration, in particular with reference to the reconstruction of the roof. Aware of the complexity of this topic, this contribution aims at exploring two possibilities, namely, on the one hand, that the fragments of tiles constitute elements supported by a wooden structure, and on the other hand, that they are structural elements of a stone system subjected to compressive stresses. Our contribution intends to serve as food for thought on the need for archaeological studies to be accompanied not only by advanced surveys in the field, aimed at the precise definition of the geometry of the finds, but also by architectural and structural investigations which make it possible to verify the feasibility of the hypothetical reconstructions of the architectural elements aware of the construction techniques used in the past

    Extruded Expanded Polystyrene Sheets Coated by TiO2 as New Photocatalitic Materials for Foodstuffs Packaging

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    Nanostructured, photoactive anatase TiO2 sol prepared under very mild conditions using titanium tetraisopropoxide as the precursor is used to functionalise extruded expanded polystyrene (XPS) sheets by spray-coating resulting in stable and active materials functionalised by TiO2 nanoparticles. Photocatalytic tests of these sheets performed in a batch reactor in gas–solid system under UV irradiation show their successful activity in degrading probe molecules (2-propanol, trimethylamine and ethene). Raman spectra ensure the deposition of TiO2 as crystalline anatase phase on the polymer surface. The presence of TiO2 with respect to polymer surface can be observed in SEM images coupled to EDAX mapping allowing to monitor the surface morphology and the distribution of TiO2 particles. Finally thermoforming of these sheets in industrial standard equipment leads to useful containers for foodstuffs

    Characterization of laser propagation through turbulent media by quantifiers based on the wavelet transform: dynamic study

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    We analyze, within the wavelet theory framework, the wandering over a screen of the centroid of a laser beam after it has propagated through a time-changing laboratory-generated turbulence. Following a previous work (Fractals 12 (2004) 223) two quantifiers are used, the Hurst parameter, HH, and the Normalized Total Wavelet Entropy, NTWS\text{NTWS}. The temporal evolution of both quantifiers, obtained from the laser spot data stream is studied and compared. This allows us to extract information of the stochastic process associated to the turbulence dynamics.Comment: 11 pages, 3 figures, accepted to be published in Physica

    Prediction of the service life of brick/stone masonry damaged by salt crystallisation: application of a stochastic model

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    An attempt has been made within a EC Contract, to establish the maximum salt content in brick and stone masonry, below which the surface protection treatments do not fail. Crystallisation tests were carried out on treated and untreated brick and limestone masonry specimens. A large number of tests were previously carried out on the single units used for the masonry specimens. Salt solutions with two low concentrations of sodium sulphate were inserted in masonry wallettes treated with a water based water repellent or with a consolidant. On the basis of the recorded experimental data, a suitable damage parameter describing the material deterioration process has been chosen. The parameter assumed is the loss of surface material. The deterioration process could be interpreted as a stochastic process L(t,l), function of time t and damage l. In this way, for differen t damage levels l it is possible to build the fragility curve. By using this approach the magnitude of the expected damage over time and the occurrence time of it can be predicted. The results will allow for the investigation on the durability of materials with respect to the prediction treatments and on the decay process of single and composite materials

    Historic roof structures: life-cycle assessment and selective maintenance strategies

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    Many industrial and military constructions built between the end of the IXX century and the first years of the XX century show long span roof structures constructed using slender steel truss members. This characteristic makes the structures almost invisible and the interior space appears larger than it is. After 100 years or more, structures like these are still in good conditions although they may have fallen into disuse and neglect. Usually these buildings are protected by Cultural Heritage regulations. Therefore, it would be interesting to define suitable intervention strategies to maintain, conserve and possibly reuse them. This paper compares three dif-ferent steel roof trusses, covering some buildings of a military installation in Pavia (Northern Italy), built from the end of the IXX century. The residual capacity has been probabilistically evaluated in order to check the efficiency of the most vulnerable members of the structures and investigate systems’ robustness in case of sudden failure of the critical components. The method proposed can be considered as a reliable approach to recognise which structural element is most like to fail, and schedule proper selective maintenance interven-tions
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