119,886 research outputs found
Optical method for measuring the volume fraction of granular media: Application to faced-centered cubic lattices of monodisperse spheres
No full textIn order to understand the dynamics of granular flows, one must have knowledge about the solid volume fraction. However, its reliable experimental estimation is still a challenging task. Here, we present the application of a stochastic-optical method (SOM) [L. Sarno et al., Granul. Matter 18, 80 (2016)10.1007/s10035-016-0676-3] to an array of spheres arranged according to faced-centered cubic lattices, where spheres' locations are known a priori. The purpose of this study is to test the robustness of the image binarization algorithm, introduced in the SOM for the indirect estimation of the near-wall volume fraction through an optically measurable quantity, defined as two-dimensional volume fraction. A comprehensive range of volume fractions and illumination conditions are numerically and experimentally investigated. The proposed binarization algorithm is found to yield reasonably accurate estimations of the two-dimensional volume fraction with a root-mean-square error smaller than 0.03 for all investigated illumination conditions. A slightly worse performance is observed for samples with relatively low volume fractions (<0.3), where the binarization algorithm occasionally cannot identify the surface elements in the second and third layers of the regular lattice
Sulla subsidenza dell'abitato di Sarno
No full textNel Comune di sarno si sta verificando un fenomeno di subsidenza che ha causato gravi danni a alcuni edifici. Per individuare le cause sono state eseguite numerose indagini di sito e di laboratori
Toward a new paradigm in open economy modeling: where do we stand?
No full textThis paper provides a selective, up-to-date survey of the recent, fast-growing literature on new open economy macroeconomics. Lucio Sarno begins with a review of the seminal paper in this literature, describing the baseline model proposed therein. He then covers a number of variants and generalizations of the baseline model involving the allowance for nominal rigidities, pricing to market, alternative preference specifications, and alternative financial markets structures. The author also discusses the recent stochastic extensions of these models, especially focusing on their implications for the link between risk and exchange rates and on new directions for the relevant literature.Econometric models ; Macroeconomics
Una tomba di alto rango dell'VIII secolo a.C. da San Marzano sul Sarno
No full textViene pubblicato un importante corredo funerario aristocratico dell'VIII secolo a.C. ritrovato a San Marzano sul Sarno. Grazie a nuovi dati emersi da questo contesto vengono messi a fuoco alcuni rilevanti fenomeni storici, tra cui l'affermazione di una cultura internazionale tra le élites indigene dell'VIII secolo a.C., e l'esistenza di relazioni di scambio intrattenute dai principi indigeni della Valle del Sarno con i Greci e in particolare con Pitecusa fin dal terzo quarto dell'VIII secolo a.C
Experimental Tests on Full Scale RC Unretrofitted Frame and Retrofitted with Buckling Restrained Braces
No full textThe results of experimental tests carried out on reinforced concrete (RC) full-scale 2-storey 2-bays framed buildings are presented. The unretrofitted frame was designed for gravity loads only and without seismic details; such frame was assumed as a benchmark system in this study. A similar RC frame was retrofitted with buckling-restrained braces (BRBs). The earthquake structural performance of both prototypes was investigated experimentally using displacement-controlled pushover static and cyclic lateral loads. Modal response properties of the prototypes were also determined before and after the occurrence of structural damage. The results of the dynamic response analyses were utilized to assess the existing design rules for the estimation of the elastic and inelastic period of vibrations. Similarly, the values of equivalent damping were compared with code-base relationships. It was found that the existing formulations need major revisions when they are used to predict the structural response of as-built RC framed buildings. The equivalent damping ratio ??eq was augmented by more than 50% when the BRBs was employed as bracing system. For the retrofitted frame, the overstrength ?? and the ductility μ are 1.6 and 4.1, respectively; the estimated R-factor is 6.5. The use of BRBs is thus a viable means to enhance efficiently the lateral stiffness and strength, the energy absorption and dissipation capacity of the existing RC substandard frame buildings. The foundation systems and the existing members of the superstructure are generally not overstressed as the seismic demand imposed on them can be controlled by the axial stiffness and the yielding force of the BRBs
Validation of numerical models for hospital building contents: rigid blocks and FEM models
No full textThe post-earthquake functionality of hospital buildings is an essential performance objective to achieve in a modern resilient community (Bruneau and Reinhorn, 2007). Such a performance may, however, be impaired due to the damage to non-structural components and building contents. Recent surveys carried out in the aftermath of major world-wide earthquakes (e.g. (Di Sarno et al., 2013, Jacques et al., 2014, Masi et al., 2014, among others) have shown that the overturning of cabinets, containing medical files with patient details, the failure of electronic panels is a typical non-structural component damage recorded after moderate-to-large earthquakes. Hazardous contaminants may also be released when medical cabinets and bookshelves overturn; hence there is a number of dangerous consequences caused by the lack of adequate seismic design. Comprehensive experimental and numerical studies were carried out in the last decade to investigate the seismic performance of a variety of furniture items, medical appliances and service utilities of typical hospital buildings and pharmacies, e.g. (Cosenza et al., 2014, Furukawa et al., 2013, Kuo et al., 2011). Numerical modeling of such components is still a key issue to be addressed.
In this study, simplified finite element models of the tested components have also been implemented in software platforms to adequately simulate the dynamic properties of sample medical components. Different numerical modeling approaches are validated upon the outcomes of a comprehensive experimental campaign on hospital building contents carried out by shake table testing at the University of Naples Federico II, Italy.
Finite element modeling approach is adopted to investigate the dynamic behavior of hospital cabinets in case they do not exhibit any rocking mechanism, i.e. pre-rocking behavior. The validation of a FEM model for the dynamic performance of cabinets is presented. Its ability to reproduce horizontal acceleration in the cabinets is also discussed. The developed numerical model gave a fairly good matching in terms of natural frequencies of the sample components. Nonlinear dynamic analyses are performed on the defined models. Recorded table acceleration are applied at the base of both the cabinets for the three different test groups. It is concluded that the defined model is able to recognize the occurrence of the rocking mechanism in the cabinets.
Medical components, such as the tested cabinets, typically exhibits a rocking behavior as the seismic intensity increases. Thus, the dynamic behavior of rigid blocks is investigated for the post-rocking behavior of cabinets. Tested cabinets are modelled as equivalent rigid blocks and subjected to the experimental base accelerations. The ability to predict the occurrence of both rocking mechanism and overturning is verified. Given the good model fidelity, a preliminary study is performed aimed at the identification of the most efficient seismic intensity measure (IM) for rigid blocks and the influence of the geometric properties of rigid blocks on their dynamic performanc
Psychological consequences of the 1998 landslide in Sarno, Italy: A community study
No full textObjective: This community study assessed the prevalence of posttraumatic stress disorder (PTSD) and the psychosocial consequences of the landslide which occurred in Sarno, Southern Italy, in May 1998. Method: A random sample (n=272) of the population living in the highest risk area of Sarno, and a control group recruited in a small town situated near the disaster area, but not affected by the event, were assessed 1 year after the disaster by standardized instruments. Results: Of the subjects recruited in Sarno, 27.6% met DSM-IV criteria for PTSD; 59% subjects recruited in Sarno and 35% of the control group were identified as 'probable cases' by the GHQ-30 (P < 0.0001). Subjects recruited in Sarno had significantly higher scores on the four GHQ-30 subscales identified by factor analysis. Conclusion: This study emphasizes the negative impact of a natural catastrophic event on mental health, and the need for preventive interventions
Seismic Retrofitting with Buckling Restrained Braces: Application to An Existing Non-Ductile RC Framed Building
No full textThis paper assesses the seismic performance of typical reinforced concrete (RC) existingframed structures designed for gravity loads only. The sample two-storey structural system exhibits high vulnerability, i.e. low lateral resistance and limited translation ductility; hence an effective strategy scheme for seismicretrofitting was deemed necessary. Such a scheme comprises bucklingrestrained braces (BRBs) placed along the perimeter frames of the multi-storey building. The adopted design approach assumes that the global response of the inelastic framed structure is the sum of the elastic frame (primary system) and the system comprising perimeter diagonal braces (secondary system); the latter braces absorb and dissipate a large amount of hysteretic energy under earthquake ground motions. Comprehensive nonlinear static (pushover) and dynamic (response history) analyses were carried out for both the as-built and retrofitted structures to investigate the efficiency of the adopted intervention strategy. A set of seven code-compliant natural earthquake records was selected and employed to perform inelastic response history analyses at serviceability (operational and damageability limit states, OLS and DLS) and ultimate limit states (life safety and collapse prevention limit states, LSLS and CPLS). Both global and local lateral displacements are notably reduced after the seismic retrofit of the existing system. In the as-built structure, the damage is primarily concentrated at the second floor (storey mechanism); the computed interstorey drifts are 2.43% at CPLS and 1.92% at LSLS for modal distribution of lateral forces. Conversely, for the retrofitted system, the estimated values of interstorey drifts (d/h) are halved; the maximum d/h are 0.84% at CPLS (along the Y-direction) and 0.65% at LSLS (yet along the Y-direction). The values of the global overstrength Ω vary between 2.14 and 2.54 for the retrofitted structure; similarly, the translation ductility μΔ-values range between 2.07 and 2.36. The response factor (R- or q-factor) is on average equal to 5.0. It is also found that, for the braced frame, under moderate-to-high magnitude earthquakes, the average period elongation is about 30%, while for the existingbuilding the elongation is negligible (lower than 5%). The inelastic response of the existing structure is extremely limited. Conversely, BRBs are effective to enhance the ductility and energy dissipation of the sample as-built structural system. Extensive nonlinear dynamic analyses showed that more than 60% of input seismic energy is dissipated by the BRBs at ultimate limit states. The estimated maximum axial ductility of the braces is about 10; the latter value of translation ductility is compliant with BRBs available on the market. At DLS, the latter devices exhibit an elastic behaviour. It can thus be concluded that, under moderate and high magnitude earthquakes, the damage is concentrated in the added dampers and the response of the existingRCframed structure (bare frame) is chiefly elastic
Le indagini dell’Università di Padova presso le Terme del Sarno a Pompei (VIII 2, 17-21)
No full textBetween 2016 and 2017 the University of Padua worked in Pompeii within the MACH Project with the aim of developing an integrated approach for the study of ancient buildings and archaeological sites. As case study, the Sarno Bath complex was selected, located along the southern border of the city (VIII 2, 17-21): a fi ve-story building, where residential areas, a public-private bath, storages coexisted interconnected. Th e paper presents some relevant results on three aspects: a critical review of the previous studies, the building plan in its last phase, the environmental context outside of the Sarno complex, in the suburbs of the city
Service innovation within new public governance theories e-platforms as smart service systems for public utilities
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