417 research outputs found

    Full Scale Reinforced Concrete Beam-Column Joints Strengthened with Steel Reinforced Polymer Systems

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    This paper presents the results of an experimental campaign performed at the Laboratory of Materials and Structural Testing of the University of Salerno (Italy) in order to investigate the seismic performance of reinforced concrete (RC) beam-column joints strengthened with steel reinforced polymer (SRP) systems. With the aim to represent typical façade frames' beam-column subassemblies found in existing RC buildings, specimens were provided with two short beam stubs orthogonal to the main beam and were designed with inadequate seismic details. Five members were strengthened by using two different SRP layouts while the remaining ones were used as benchmarks. Once damaged, two specimens were also repaired, retrofitted with SRP, and subjected to cyclic test again. The results of cyclic tests performed on SRP strengthened joints are examined through a comparison with the outcomes of the previous experimental program including companion specimens not provided with transverse beam stubs and strengthened by carbon fiber-reinforced polymer (CFRP) systems. In particular, both qualitative and quantitative considerations about the influence of the confining effect provided by the secondary beams on the joint response, the suitability of all the adopted strengthening solutions (SRP/CFRP systems), the performances and the failure modes experienced in the several cases studied are provided

    Modelling defects in Ni-Al with EAM and DFT calculations

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    We present detailed comparisons between the results of embedded atom model (EAM) and density functional theory (DFT) calculations on defected Ni alloy systems. We find that the EAM interatomic potentials reproduce low-temperature structural properties in both the γ and γ′{{\gamma}^{\prime}} phases, and yield accurate atomic forces in bulk-like configurations even at temperatures as high as  ~1200 K. However, they fail to describe more complex chemical bonding, in configurations including defects such as vacancies or dislocations, for which we observe significant deviations between the EAM and DFT forces, suggesting that derived properties such as (free) energy barriers to vacancy migration and dislocation glide may also be inaccurate. Testing against full DFT calculations further reveals that these deviations have a local character, and are typically severe only up to the first or second neighbours of the defect. This suggests that a QM/MM approach can be used to accurately reproduce QM observables, fully exploiting the EAM potential efficiency in the MM zone. This approach could be easily extended to ternary systems for which developing a reliable and fully transferable EAM parameterisation would be extremely challenging e.g. Ni alloy model systems with a W or Re-containing QM zone

    Biotechnological and digital revolution for climate-smart plant breeding

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    Climate change, associated with global warming, extreme weather events, and increasing incidence of weeds, pests and pathogens, is strongly influencing major cropping systems. In this challenging scenario, miscellaneous strategies are needed to expedite the rate of genetic gains with the purpose of developing novel varieties. Large plant breeding populations, efficient high-throughput technologies, big data management tools, and downstream biotechnology and molecular techniques are the pillars on which next generation breeding is based. In this review, we describe the toolbox the breeder has to face the challenges imposed by climate change, remark on the key role bioinformatics plays in the analysis and interpretation of big “omics„ data, and acknowledge all the benefits that have been introduced into breeding strategies with the biotechnological and digital revolution

    the landscapes of the ancient appia project formation and degeneration processes in landscapes stratification of the benevento area

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    In this work we intend to illustrate methods and tools used for evaluating and defining some of the post-depositional processes of the archaeological record in the Eastern Beneventan landscapes. Our research aims especially to recognise the traces of the "longue duree" phenomena, highlighting what may be considered a result of the past still observable in the present. Which are the tools that allow us to identify landscapes marks, anthropogenic and environmental processes responsible of the survival or, conversely, of the obliteration of the ancient forms? A first approach attempts to create a dialogic relationship with the historical cartographic documents (such as ancient cadastres, notarial instruments, boundary disputes) and sheds light on the dynamics of the perceptible transformations of landscapes, bringing back an overall view of their contextual distinctive traits. This ensures the identification of "ecofacts" and "artefacts" that contributes to the structuration of the landscapes that have occurred over time as stratified units. A second procedure involves the reading of the historical information combined with the environmental one, through an archaeomorphological approach. The study has provided an overlap among the ancient and modern rural fabrics (for example roads, canals, talwegs, agrarian boundaries) and the geomorphological dynamics, with the aim of discerning the forms of degradation and to define, when possible, a relative chronology. Such an approach evaluates the distribution of surface artefacts and their spatial and temporal characteristics, enabling recording of the higher or lower level of degradation in the archaeological record, emphasising those landscapes units considered of high information potential

    Pedicularis L. Genus. Systematics, botany, phytochemistry, chemotaxonomy, ethnopharmacology, and other

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    In this review, the relevance of the plant species belonging to the Pedicularis L. genus has been considered from different points of view. Particular emphasis was given to phytochemistry and ethnopharmacology, since several classes of natural compounds have been reported within this genus and many of its species are well known to be employed in the traditional medicines of many Asian countries. Some important conclusions on the chemotaxonomic and chemosystematic aspects of the genus have also been provided for the first time. Actually, this work represents the first total comprehensive review on this genus

    A case study for spacegate point-to-point transportation: Evaluation of a reference end-to-end mission operations and assessment of the associated safety aspects

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    The ALTEC-conducted Spacegate feasibility study addresses the opportunities offered by the sub-orbital flight with special emphasis to future generation transportation. Pursuing the same systemic methodology of the initial Spacegate definition activities, this paper focuses on some specific aspects of suborbital operations and outlines a top level end-to-end operating cycle for a reference suborbital mission spanning from pre-flight, to flight, re-entry and post landing operations and associated Ground Segment. Special focus is given to identification of suitable locations in Italy for suborbital operations, and to liftoff and re-entry phases; the results of specific simulations are also reported, showing some lift off options and the feasibility of the spiral shaped descent maneuver that improves the pilot controllability of the vehicle during the re-entry phase. Further, this paper outlines within the selected reference mission, the main safety aspects considered as driving factors in planning and implementing future generation transportation; areas such as launch/landing range and relevant risk management/mitigation policies, as well as selection of safety driving criteria in the definition of trajectories and space transition corridors, and capabilities to monitor the vehicle ascent and re-entry will be assessed. Safety regulations will also be evaluated to protect launch range, drive spaceport site selection and consequently the ability of the spaceport to accommodate large numbers of passengers and participants, as well as a number of simultaneous operations such as training, vehicle integration tasks, and passenger preparation for flight. For human flight in general, and in particular for commercial point to point activities at this early stage, it is vital to minimize risk since a fatal accident at the very beginning of flights will put the entire business in jeopardy. The regulatory challenges with regards to safety will also be outlined in this paper, related to executing Spacegate activities in Europe and collaborations with the involved Agencies in the USA and Europe (FAA, ENAC, ENAV, SESAR, EASA) will be explored; in particular, some initiatives have already been started, that include active ALTEC participation to the IAASS Space Safety Technical Committee (SSTC) that was created to contribute to the advancement of the Safety in the area of the "Commercial Suborbital Flight"
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