1,721,061 research outputs found
Nuovi marcatori microsatelliti per lo studio del germoplasma di olivo (Olea Europaea L.) coltivato in Puglia
No full textSeismic vulnerability of industrial steel structures with masonry infills using a numerical approach
Full text linkRecent earthquakes have highlighted the high vulnerability of the industrial structures that are not specifically designed for accounting seismic forces. Among them, a widespread typology is characterised by steel structures without bracing or other anti-seismic details and with masonry infills. With the aim of increasing the knowledge on the seismic behaviour of these structures, this work focuses on a mechanical-based approach for the evaluation of fragility curves for industrial areas. The exposure data are obtained by in-situ survey and acquiring information available in existing databases, like the Italian Cartis-GL one that is specifically devised for industrial structures. The variability of geometrical and mechanical data and the presence of epistemic uncertainties are considered by constructing a population of structures using the Monte Carlo method. Each structure is analysed through static-nonlinear simulations adopting mixed finite elements accounting for geometrical and constitutive nonlinearities. The approach is tested for infilled steel structures in the industrial area of the municipality of Spezzano Albanese (Italy). Results show that the presence of masonry infill drastically modifies the seismic behaviour of this structural typology. In particular, it turns out that if the mechanical contribution of the infill is neglected, the structures exhibit high damages even for low intensities of the seismic action
La gestione patrimoniale: i beni pubblici
No full text1. – Le classificazioni dei beni pubblici. 2. – I beni immobili pubblici nella crisi della tassonomia codicistica tra titolarità e utilità. 3. – Gli strumenti giuridici tradizionali per la gestione dei beni pubblici. 3.1. – La concessione di bene in proprietà pubblica. 3.2. – I principi costituzionali e la direttiva Bolkestein. 3.3. – La gestione dei beni pubblici in tempo di crisi: il baratto amministrativo. 4. – Le privatizzazioni immobiliari. 4.1. – Le dismissioni di immobili pubblici. 4.1.1. – La cartolarizzazione di beni in proprietà pubblica. 4.1.2. – I fondi comuni di investimento immobiliare. 4.1.3. – Il Piano delle alienazioni e valorizzazioni immobiliari allegato al bilancio delle autonomie locali. 4.2. – La valorizzazione dei beni pubblici. 4.2.1. – La concessione di valorizzazione. 5. – Il federalismo demaniale. 6. – Privatizzazioni e “razionalizzazioni” mobiliari. 7. – Le “vicissitudini” delle reti. 8. – Quale ruolo per i beni pubblici
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A hybrid virtual element formulation for 2D elasticity problems
No full textIn this paper, a hybrid variational framework for the Virtual Element Method (VEM) is proposed and a family of polygonal elements for plane elasticity is developed. Under specific assumptions, it is proved that the minimization of Total Potential Energy and the projection operation typical of enhanced VEM can be deduced from the stationary condition of the Hellinger–Reissner mixed functional. Since the designed elements can be regarded as either enhanced VEM or hybrid finite elements, they are named as Hybrid Virtual Element Method (HVEM). The primary variables are the displacements along the element boundary and the stress field within the element domain.
The assumed stress field is expressed on a polynomial basis that satisfies the divergence-free condition. In the HVEM formulation, stabilization-free elements can be obtained using two concepts, namely hyper-stability and iso-stability. In particular, the iso-stable cases show the best solution in recovering both displacement and stress fields. Several numerical applications are developed, assessing the stability for a single distorted element. The proposed family of HVEM proves to be accurate, also if coarse meshes are used. Additionally, the effectiveness of the proposed HVEM is demonstrated for typical structural elements, testing the convergence rate and comparing the results with analytic or other numerical solutions
Numerical Model and Seismic Vulnerability of Infilled Industrial Steel Structures
No full textA numerical framework for the seismic vulnerability assessment of industrial steel structures with masonry infills is presented. This peculiar structural typology has been extensively observed in many industrial areas in the Italian territory and is commonly characterized by the absence of bracings or any anti-seismic design criteria. As such, masonry infills represent the main seismic resistant structural component which, then, cannot be neglected in the vulnerability analyses. An efficient finite element model is adopted to simulate the structural nonlinear behaviour, considering both geometrical and constitutive nonlinearities. Epistemic uncertainties related to the geometric data and the mechanical characteristics of steel and masonry are considered. The approach is tested for infilled steel structures in the industrial area of Spezzano Albanese, in southern Italy. Fragility curves are constructed considering or not considering the presence of infills and the results show that the seismic behaviour is drastically different in the two cases. In particular, it turns out that if the mechanical contribution of the infill is neglected, the structures exhibit high damage even for low intensities of the seismic action
Dynamic and geometrically nonlinear analysis of folded plate structures by a H-R mixed 4-node flat shell element
No full textA simple, flat-shell finite element based on a Hellinger-Reissner formulation, free from locking and spurious zero-energy modes is presented. The element exhibits very good performances in the linear elastic context and in dynamics and buckling benchmarks, so showing its aptitude for geometrically nonlinear analyses when coupled with a corotational approach
Modeling and designing micro- and nano-structured metamaterials: Towards the application of exotic behaviors
No full textThe lack of suitable computational methods has significantly restricted the creativity of engineers in designing the materials to be used in technological applications. When one wants exact analytical solutions for a given physical system, then usually drastic and restrictive simplifying assumptions are needed. In particular, homogeneity of physical and geometrical properties at lower length-scale is the standard assumption in continuum mechanics. On the other hand, it is well-known since the pioneering work of Gabrio Piola, and then re-established in the works by Mindlin, Toupin, Green, Adkins and Germain, that it is possible to synthetically describe microscopic inhomogeneity by means of field theories incorporating additional kinematical fields. The characteristic length-scale affecting macro-behavior can even be of the order of nanometers, in which case the intuition due to Richard Feynman about the importance of quantum effects at macro-scale could open the path to technological advancements. In the present paper we review some of the literature in the field and try to indicate some research perspectives that seem to us potentially ground-breaking. In particular, following the suggestion of Professor dell’Isola, we briefly describe his concept of pantographic lattices and sheets whose importance in nano-technology could be relevant
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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