159 research outputs found

    Effect of retrofit interventions on seismic fragility of Italian residential masonry buildings

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    In this paper, the vulnerability of ordinary unreinforced masonry (URM) buildings is analyzed, and the literature related to possible seismic retrofit interventions is reviewed in order to investigate their feasibility and effectiveness. These interventions are then simulated on a data-base of 445 buildings through Vulnus_4.0 software, that performs simplified mechanical analyses accounting for both global and local behavior of masonry buildings. The fragility of each building is assessed both in its as-built state and after the simulation of retrofit interventions. Fragility curves are then processed, and a fragility model for four building typologies is obtained for the as -built and the seismic retrofitted configurations. Lastly, mean damage maps are elaborated, and the performance of the proposed retrofit interventions is analyzed. The results of this work allow evaluating and comparing the improvement of seismic behavior brought by various retrofit in-terventions and could serve as a basis for further theoretical studies and for practical design in real cases

    Characterisation of an urban bridge portfolio and multi-risk prioritisation accounting for deterioration and seismic vulnerability

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    This contribution proposes a procedure to prioritise retrofit interventions on stocks of bridges according to their seismic vulnerability. The procedure also combines a previously presented approach to evaluate deterioration effects on bridges at a territorial scale. Thereby, the combi-nation of the two approaches provides a multi-risk classification method for bridge stocks. This method also allows refined prioritisation within each class, based on the proposed quantitative indices and on multicriteria decision-making methods. The method was applied to the bridge stock managed by the municipality of Padova, in North-East Italy. First, an extensive charac-terisation of the analysed stock is provided, according to typological, geometric, and structural parameters. Then, the application of the combined approach is presented, highlighting which bridge types resulted more vulnerable to either seismic actions or deterioration effects

    Mechanics-based fragility curves for Italian residential URM buildings

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    Seismic risk assessment at the territorial level is now widely recognised as essential for countries with intense seismic activity, such as Italy. Academia is called to give its contribution in order to synergically deepen the knowledge about the various components of this risk, starting from the complex evaluation of vulnerability of the built heritage. In line with this, a mechanics-based seismic fragility model for Italian residential masonry buildings was developed and presented in this paper. This model is based on the classification of the building stock in macro-typologies, defined by age of construction and number of storeys, which being information available at national level, allow simulating damage scenarios and carrying out risk analyses on a territorial scale. The model is developed on the fragility of over 500 buildings, sampled according to national representativeness criteria and analysed through the Vulnus_4.0 software. The calculated fragility functions were extended on the basis of a reference model available in the literature, which provides generic fragilities for the EMS98 vulnerability classes, thus obtaining a fragility model defined on the five EMS98 damage states. Lastly, to assess the reliability of the proposed model, this was used to simulate damage scenarios due to the 2009 L’Aquila earthquake. Overall, the comparison between model results and observed damage showed a good fit, proving the model effectiveness

    Sex differences in the association of psychological status with measures of physical activity and sedentary behaviour in adults with type 2 diabetes

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    Aim – To assess the association of psychological variables on leisure time physical activity and sedentary time in men and women with type 2 diabetes mellitus (T2D). Methods – In this cross-sectional study, we evaluated 163 patients with T2D, consecutively recruited at the Diabetes Centre of the Verona General Hospital. Scores on depression and anxiety symptoms, psychosocial factors (including self-efficacy, perceived interference, perceived severity, social support, misguided support behaviour, spouse’s positive behaviour), physical activity and time spent sitting were ascertained using questionnaires responses to the Beck Depression Inventory-II, Beck Anxiety Inventory, Multidimensional Diabetes Questionnaire, International Physical Activity Questionnaire. Results – Physical activity was significantly associated with higher social support in women, and with increased self-efficacy in men. Sedentary time was significantly associated with higher perceived interference, anxiety and depressive symptoms, and with reduced diabetes self-efficacy in women, while it was associated solely with anxiety in men. Depressive symptoms and self-efficacy in women and anxiety symptoms in men were independent predictors of sedentary time when entered in a multivariable regression model also including age, BMI, hemoglobin A1c, diabetes duration, perceived interference and self-efficacy as covariates. Conclusions – Lower self-efficacy and higher symptoms of depression were closely associated with increased sedentary time in women, but not in men, with T2D. It is possible that individualized behavioral interventions designed to reduce depressive symptoms and to improve diabetes self-efficacy would ultimately reduce sedentary behaviours, particularly in women with T2D

    Correlated Λd\Lambda d pairs from the KstopAΛdAK^{-}_{stop} A \to \Lambda d A' reaction

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    Correlated Λd\Lambda d pairs emitted after the absorption of negative kaons at rest KstopAΛdAK^{-}_{stop}A\to \Lambda d A' in light nuclei 6Li^6Li and 12C^{12}C are studied. Λ\Lambda-hyperons and deuterons are found to be preferentially emitted in opposite directions. The Λd\Lambda d invariant mass spectrum of 6Li^6Li shows a bump whose mass is 3251±\pm6 MeV/c2^2. The bump mass (binding energy), width and yield are reported. The appearance of a bump is discussed in the realm of the [Kˉ3N\bar{K}3N] clustering process in nuclei. The experiment was performed with the FINUDA spectrometer at DAΦ\PhiNE (LNF).Comment: 13 pages, 5 figures, accepted for publication in Phys. Lett.

    A new look at loop quantum gravity

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    I describe a possible perspective on the current state of loop quantum gravity, at the light of the developments of the last years. I point out that a theory is now available, having a well-defined background-independent kinematics and a dynamics allowing transition amplitudes to be computed explicitly in different regimes. I underline the fact that the dynamics can be given in terms of a simple vertex function, largely determined by locality, diffeomorphism invariance and local Lorentz invariance. I emphasize the importance of approximations. I list open problems.Comment: 15 pages, 5 figure

    Flow angle from intermediate mass fragment measurements

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    Directed sideward flow of light charged particles and intermediate mass fragments was measured in different symmetric reactions at bombarding energies from 90 to 800 AMeV. The flow parameter is found to increase with the charge of the detected fragment up to Z = 3-4 and then turns into saturation for heavier fragments. Guided by simple simulations of an anisotropic expanding thermal source, we show that the value at saturation can provide a good estimate of the flow angle, Θflow\Theta_{flow}, in the participant region. It is found that Θflow\Theta_{flow} depends strongly on the impact parameter. The excitation function of Θflow\Theta_{flow} reveals striking deviations from the ideal hydrodynamical scaling. The data exhibit a steep rise of \Theta_{\flow} to a maximum at around 250-400 AMeV, followed by a moderate decrease as the bombarding energy increases further.Comment: 28 pages Revtex, 6 figures (ps files), to appear in Nucl.Phys.

    Loop quantum gravity: the first twenty five years

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    This is a review paper invited by the journal "Classical ad Quantum Gravity" for a "Cluster Issue" on approaches to quantum gravity. I give a synthetic presentation of loop gravity. I spell-out the aims of the theory and compare the results obtained with the initial hopes that motivated the early interest in this research direction. I give my own perspective on the status of the program and attempt of a critical evaluation of its successes and limits.Comment: 24 pages, 3 figure

    First Results on 12Lambda-C production at DAPHNE

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    Lambda-hypernuclei are produced and studied, with the FINUDA spectrometer, for the first time at an e+e- collider: DAPHNE, the Frascati phi-factory. The slow negative kaons from phi(1020) decay are stopped in thin (0.2 g/cm^2) nuclear targets, and Lambda-hypernuclei formation is detected by measuring the momentum of the outgoing pi^-. A preliminary analysis on 12Lambda-C shows an energy resolution of 1.29 MeV FWHM on the hypernuclear levels, the best obtained so far with magnetic spectrometers at hadron facilities. Capture rates for the ground state and the excited ones are reported, and compared with previous experiments.Comment: 15 pages, 5 figures. v2: one reference updated. Accepted for publication in Phys. Lett.
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